G2Cdb::Gene report

Gene id
Gene symbol
Homo sapiens
GDP dissociation inhibitor 1
G00000254 (Mus musculus)

Databases (8)

Curated Gene
OTTHUMG00000033293 (Vega human gene)
ENSG00000203879 (Ensembl human gene)
2664 (Entrez Gene)
573 (G2Cdb plasticity & disease)
GDI1 (GeneCards)
300104 (OMIM)
Marker Symbol
HGNC:4226 (HGNC)
Protein Sequence
P31150 (UniProt)

Synonyms (4)

  • FLJ41411
  • OPHN2
  • XAP-4

Literature (44)

Pubmed - other

  • GDI-1 preferably interacts with Rab10 in insulin-stimulated GLUT4 translocation.

    Chen Y, Deng Y, Zhang J, Yang L, Xie X and Xu T

    National Key Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.

    Insulin stimulates GLUT4 (glucose transporter 4) translocation in adipocytes and muscles. An emerging picture is that Rab10 could bridge the gap between the insulin signalling cascade and GLUT4 translocation in adipocytes. In the present study, two potential effectors of Rab10, GDI (guanine-nucleotide-dissociation inhibitor)-1 and GDI-2, are characterized in respect to their roles in insulin-stimulated GLUT4 translocation. It is shown that both GDI-1 and GDI-2 exhibit similar distribution to GLUT4 and Rab10 at the TGN (trans-Golgi network) and periphery structures. Meanwhile, GDI-1 clearly interacts with Rab10 with higher affinity, as shown by both immunoprecipitation and in vivo FRET (fluorescence resonance energy transfer). In addition, the participation of GDIs in GLUT4 translocation is illustrated when overexpression of either GDI inhibits insulin-stimulated GLUT4 translocation in 3T3-L1 adipocytes. Taken together, we propose that GDI-1 is preferentially involved in insulin-stimulated GLUT4 translocation through facilitating Rab10 recycling.

    The Biochemical journal 2009;422;2;229-35

  • [Relationship between the polymorphisms of GDI1, children NSMR and their intelligence in Qinba region].

    Zhang KJ, DU Y, Zheng ZJ, Gao XC, Huang SP, Li RL, Chen C and Zhang FC

    College of Life Science, Institute of Population and Health, Northwest University, Xi'an 710069, China. kejinzhang@163.com

    The subjects of this study were recruited from Zha Shui and An Kang counties in the Qinba mountain region located in Middle-west China. The present study discussed the relationship between the variations of GDI1 with the children NSMR and their intelligence levels. The case-control association analysis method was used to analyze the association between the polymorphisms of two functional SNPs (rs2276462 and rs11549300) located in splicing site of the seventh exon and the eighth exon respectively, with NSMR and their different intelligence levels. It does not find out the polymorphism of rs2276462, because of its conservation. The results of case-control analysis indicated that, no association between the rs11549300 polymorphisms and children NSMR (P >0.05), but its polymorphisms may be related to intelligence levels of children in Qinba region (P =0.03). And a further work should be done to verify the conclusion of this study using the more genetic markers of GDI1 in a larger sample.

    Yi chuan = Hereditas 2008;30;5;590-4

  • Large-scale mapping of human protein-protein interactions by mass spectrometry.

    Ewing RM, Chu P, Elisma F, Li H, Taylor P, Climie S, McBroom-Cerajewski L, Robinson MD, O'Connor L, Li M, Taylor R, Dharsee M, Ho Y, Heilbut A, Moore L, Zhang S, Ornatsky O, Bukhman YV, Ethier M, Sheng Y, Vasilescu J, Abu-Farha M, Lambert JP, Duewel HS, Stewart II, Kuehl B, Hogue K, Colwill K, Gladwish K, Muskat B, Kinach R, Adams SL, Moran MF, Morin GB, Topaloglou T and Figeys D

    Protana, Toronto, Ontario, Canada.

    Mapping protein-protein interactions is an invaluable tool for understanding protein function. Here, we report the first large-scale study of protein-protein interactions in human cells using a mass spectrometry-based approach. The study maps protein interactions for 338 bait proteins that were selected based on known or suspected disease and functional associations. Large-scale immunoprecipitation of Flag-tagged versions of these proteins followed by LC-ESI-MS/MS analysis resulted in the identification of 24,540 potential protein interactions. False positives and redundant hits were filtered out using empirical criteria and a calculated interaction confidence score, producing a data set of 6463 interactions between 2235 distinct proteins. This data set was further cross-validated using previously published and predicted human protein interactions. In-depth mining of the data set shows that it represents a valuable source of novel protein-protein interactions with relevance to human diseases. In addition, via our preliminary analysis, we report many novel protein interactions and pathway associations.

    Molecular systems biology 2007;3;89

  • A protein-protein interaction network for human inherited ataxias and disorders of Purkinje cell degeneration.

    Lim J, Hao T, Shaw C, Patel AJ, Szabó G, Rual JF, Fisk CJ, Li N, Smolyar A, Hill DE, Barabási AL, Vidal M and Zoghbi HY

    Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA.

    Many human inherited neurodegenerative disorders are characterized by loss of balance due to cerebellar Purkinje cell (PC) degeneration. Although the disease-causing mutations have been identified for a number of these disorders, the normal functions of the proteins involved remain, in many cases, unknown. To gain insight into the function of proteins involved in PC degeneration, we developed an interaction network for 54 proteins involved in 23 inherited ataxias and expanded the network by incorporating literature-curated and evolutionarily conserved interactions. We identified 770 mostly novel protein-protein interactions using a stringent yeast two-hybrid screen; of 75 pairs tested, 83% of the interactions were verified in mammalian cells. Many ataxia-causing proteins share interacting partners, a subset of which have been found to modify neurodegeneration in animal models. This interactome thus provides a tool for understanding pathogenic mechanisms common for this class of neurodegenerative disorders and for identifying candidate genes for inherited ataxias.

    Funded by: NICHD NIH HHS: HD24064; NINDS NIH HHS: NS27699

    Cell 2006;125;4;801-14

  • New insights into potential functions for the protein 4.1 superfamily of proteins in kidney epithelium.

    Calinisan V, Gravem D, Chen RP, Brittin S, Mohandas N, Lecomte MC and Gascard P

    Life Sciences Division, Department of Genome Biology, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.

    Members of the protein 4.1 family of adapter proteins are expressed in a broad panel of tissues including various epithelia where they likely play an important role in maintenance of cell architecture and polarity and in control of cell proliferation. We have recently characterized the structure and distribution of three members of the protein 4.1 family, 4.1B, 4.1R and 4.1N, in mouse kidney. We describe here binding partners for renal 4.1 proteins, identified through the screening of a rat kidney yeast two-hybrid system cDNA library. The identification of putative protein 4.1-based complexes enables us to envision potential functions for 4.1 proteins in kidney: organization of signaling complexes, response to osmotic stress, protein trafficking, and control of cell proliferation. We discuss the relevance of these protein 4.1-based interactions in kidney physio-pathology in the context of their previously identified functions in other cells and tissues. Specifically, we will focus on renal 4.1 protein interactions with beta amyloid precursor protein (beta-APP), 14-3-3 proteins, and the cell swelling-activated chloride channel pICln. We also discuss the functional relevance of another member of the protein 4.1 superfamily, ezrin, in kidney physio-pathology.

    Funded by: NIDDK NIH HHS: DK32094, DK56355

    Frontiers in bioscience : a journal and virtual library 2006;11;1646-66

  • Gene expression profiles with cDNA microarray reveal RhoGDI as a predictive marker for paclitaxel resistance in ovarian cancers.

    Goto T, Takano M, Sakamoto M, Kondo A, Hirata J, Kita T, Tsuda H, Tenjin Y and Kikuchi Y

    Department of Obstetrics and Gynecology, Saitama Medical College, Iruma-gun, Saitama 350-0495, Japan.

    In the current study, we identified paclitaxel-resistant related genes by comparing gene expression profiles of paclitaxel-resistant and parent ovarian cancer cell lines. Gene expression profiles of the human ovarian cancer cell line (KF28), cisplatin-resistant cell line (KFr13) induced from KF28, and paclitaxel-resistant cell lines (KF28TX and KFr13TX) induced by exposing KF28 and KFr13 to dose-escalating paclitaxel were compared and analyzed using cDNA microarray. Of 557 human cancer-related cDNA transcripts compared, 5 genes were found to be underexpressed and 5 genes overexpressed in the paclitaxel-resistant KF28TX, while another paclitaxel-resistant KFr13TX had 5 underexpressed and 8 overexpressed genes. Among these genes, overexpression of the ATP-binding cassette subfamily (MDR-1), Rho guanine dinucleotide phosphate dissociation inhibitor beta (RhoGDI) and insulin-like growth factor binding protein 3 (IGFBP-3) was observed in both paclitaxel-resistant cell lines. Using real-time quantitative PCR, we confirmed the array results. We therefore conclude that IGFBP-3, RhoGDI and MDR-1 were correlated with paclitaxel resistance. Moreover, immunohistochemical staining was analyzed in 22 serous ovarian cancer tissues from patients who received paclitaxel-based chemotherapy, and RhoGDI overexpression was observed more frequently in non-responsers than in responders (p=0.004). RhoGDI expression proved to be a predictive marker of paclitaxel resistance not only in paclitaxel-resistant cell lines, but also in clinical samples.

    Oncology reports 2006;15;5;1265-71

  • The LIFEdb database in 2006.

    Mehrle A, Rosenfelder H, Schupp I, del Val C, Arlt D, Hahne F, Bechtel S, Simpson J, Hofmann O, Hide W, Glatting KH, Huber W, Pepperkok R, Poustka A and Wiemann S

    Division Molecular Genome Analysis, German Cancer Research Center, Im Neuenheimer Feld 580, D-69120 Heidelberg, Germany. a.mehrle@dkfz.de

    LIFEdb (http://www.LIFEdb.de) integrates data from large-scale functional genomics assays and manual cDNA annotation with bioinformatics gene expression and protein analysis. New features of LIFEdb include (i) an updated user interface with enhanced query capabilities, (ii) a configurable output table and the option to download search results in XML, (iii) the integration of data from cell-based screening assays addressing the influence of protein-overexpression on cell proliferation and (iv) the display of the relative expression ('Electronic Northern') of the genes under investigation using curated gene expression ontology information. LIFEdb enables researchers to systematically select and characterize genes and proteins of interest, and presents data and information via its user-friendly web-based interface.

    Nucleic acids research 2006;34;Database issue;D415-8

  • Diversification of transcriptional modulation: large-scale identification and characterization of putative alternative promoters of human genes.

    Kimura K, Wakamatsu A, Suzuki Y, Ota T, Nishikawa T, Yamashita R, Yamamoto J, Sekine M, Tsuritani K, Wakaguri H, Ishii S, Sugiyama T, Saito K, Isono Y, Irie R, Kushida N, Yoneyama T, Otsuka R, Kanda K, Yokoi T, Kondo H, Wagatsuma M, Murakawa K, Ishida S, Ishibashi T, Takahashi-Fujii A, Tanase T, Nagai K, Kikuchi H, Nakai K, Isogai T and Sugano S

    Life Science Research Laboratory, Central Research Laboratory, Hitachi, Ltd., Kokubunji, Tokyo, 185-8601, Japan.

    By analyzing 1,780,295 5'-end sequences of human full-length cDNAs derived from 164 kinds of oligo-cap cDNA libraries, we identified 269,774 independent positions of transcriptional start sites (TSSs) for 14,628 human RefSeq genes. These TSSs were clustered into 30,964 clusters that were separated from each other by more than 500 bp and thus are very likely to constitute mutually distinct alternative promoters. To our surprise, at least 7674 (52%) human RefSeq genes were subject to regulation by putative alternative promoters (PAPs). On average, there were 3.1 PAPs per gene, with the composition of one CpG-island-containing promoter per 2.6 CpG-less promoters. In 17% of the PAP-containing loci, tissue-specific use of the PAPs was observed. The richest tissue sources of the tissue-specific PAPs were testis and brain. It was also intriguing that the PAP-containing promoters were enriched in the genes encoding signal transduction-related proteins and were rarer in the genes encoding extracellular proteins, possibly reflecting the varied functional requirement for and the restricted expression of those categories of genes, respectively. The patterns of the first exons were highly diverse as well. On average, there were 7.7 different splicing types of first exons per locus partly produced by the PAPs, suggesting that a wide variety of transcripts can be achieved by this mechanism. Our findings suggest that use of alternate promoters and consequent alternative use of first exons should play a pivotal role in generating the complexity required for the highly elaborated molecular systems in humans.

    Genome research 2006;16;1;55-65

  • Towards a proteome-scale map of the human protein-protein interaction network.

    Rual JF, Venkatesan K, Hao T, Hirozane-Kishikawa T, Dricot A, Li N, Berriz GF, Gibbons FD, Dreze M, Ayivi-Guedehoussou N, Klitgord N, Simon C, Boxem M, Milstein S, Rosenberg J, Goldberg DS, Zhang LV, Wong SL, Franklin G, Li S, Albala JS, Lim J, Fraughton C, Llamosas E, Cevik S, Bex C, Lamesch P, Sikorski RS, Vandenhaute J, Zoghbi HY, Smolyar A, Bosak S, Sequerra R, Doucette-Stamm L, Cusick ME, Hill DE, Roth FP and Vidal M

    Center for Cancer Systems Biology and Department of Cancer Biology, Dana-Farber Cancer Institute, Harvard Medical School, 44 Binney Street, Boston, Massachusetts 02115, USA.

    Systematic mapping of protein-protein interactions, or 'interactome' mapping, was initiated in model organisms, starting with defined biological processes and then expanding to the scale of the proteome. Although far from complete, such maps have revealed global topological and dynamic features of interactome networks that relate to known biological properties, suggesting that a human interactome map will provide insight into development and disease mechanisms at a systems level. Here we describe an initial version of a proteome-scale map of human binary protein-protein interactions. Using a stringent, high-throughput yeast two-hybrid system, we tested pairwise interactions among the products of approximately 8,100 currently available Gateway-cloned open reading frames and detected approximately 2,800 interactions. This data set, called CCSB-HI1, has a verification rate of approximately 78% as revealed by an independent co-affinity purification assay, and correlates significantly with other biological attributes. The CCSB-HI1 data set increases by approximately 70% the set of available binary interactions within the tested space and reveals more than 300 new connections to over 100 disease-associated proteins. This work represents an important step towards a systematic and comprehensive human interactome project.

    Funded by: NCI NIH HHS: R33 CA132073; NHGRI NIH HHS: P50 HG004233, R01 HG001715, RC4 HG006066, U01 HG001715; NHLBI NIH HHS: U01 HL098166

    Nature 2005;437;7062;1173-8

  • Tumor necrosis factor alpha stimulation of Rac1 activity. Role of isoprenylcysteine carboxylmethyltransferase.

    Papaharalambus C, Sajjad W, Syed A, Zhang C, Bergo MO, Alexander RW and Ahmad M

    Department of Medicine, Division of Cardiology, Emory University School of Medicine, Atlanta, Georgia 30322, USA.

    We have previously demonstrated that both isoprenylcysteine carboxylmethyltransferase (ICMT) and one of its substrates, the RhoGTPase Rac1, are critical for the tumor necrosis factor alpha (TNF alpha) stimulation of vascular cell adhesion molecule-1 expression in endothelial cells (EC). Here, we have shown that ICMT regulates TNF alpha stimulation of Rac1 activity. TNF alpha stimulation of EC increased the membrane association of Rac1, an event that is essential for Rac1 activity. ICMT inhibitor N-acetyl-S-farnesyl-L-cysteine (AFC) blocked the accumulation of Rac1 into the membrane both in resting and TNF alpha-stimulated conditions. Similarly, the membrane-associated Rac1 was lower in Icmt-deficient versus wild-type mouse embryonic fibroblasts (MEFs). TNF alpha also increased the level of GTP-Rac1, the active form of Rac1, in EC. AFC completely suppressed the TNF alpha stimulation of increase in GTP-Rac1 levels. Confocal microscopy revealed resting EC Rac1 was present in the plasma membrane and also in the perinuclear region. AFC mislocalized Rac1, both from the plasma membrane and the perinuclear region. Mislocalization of Rac1 was also observed in Icmt-deficient versus wild-type MEFs. To determine the consequences of ICMT inhibition, we investigated the effect of AFC on p38 mitogen-activated protein (MAP) kinase phosphorylation, which is downstream of Rac1. AFC inhibited the TNF alpha stimulation of p38 MAP kinase phosphorylation in EC. TNF alpha stimulation of p38 MAP kinase phosphorylation was also significantly attenuated in Icmt-deficient versus wild-type MEFs. To understand the mechanism of inhibition of Rac1 activity, we examined the effect of ICMT inhibition on the interaction of Rac1 with its inhibitor, Rho guanine nucleotide dissociation inhibitor (RhoGDI). The association of Rac1 with its inhibitor RhoGDI was dramatically increased in the Icmt-deficient versus wild-type MEFs both in resting as well as in TNF alpha-stimulated conditions, suggesting that RhoGDI was involved in inhibiting Rac1 activity under the conditions of ICMT inhibition. These results suggest that ICMT regulates Rac1 activity by controlling the interaction of Rac1 with RhoGDI. We hypothesize that ICMT regulates the release of Rac1 from RhoGDI.

    Funded by: NHLBI NIH HHS: HL60728, HL66508

    The Journal of biological chemistry 2005;280;19;18790-6

  • Immunoaffinity profiling of tyrosine phosphorylation in cancer cells.

    Rush J, Moritz A, Lee KA, Guo A, Goss VL, Spek EJ, Zhang H, Zha XM, Polakiewicz RD and Comb MJ

    Cell Signaling Technology Inc., 166B Cummings Center, Beverly, Massachusetts 01915, USA.

    Tyrosine kinases play a prominent role in human cancer, yet the oncogenic signaling pathways driving cell proliferation and survival have been difficult to identify, in part because of the complexity of the pathways and in part because of low cellular levels of tyrosine phosphorylation. In general, global phosphoproteomic approaches reveal small numbers of peptides containing phosphotyrosine. We have developed a strategy that emphasizes the phosphotyrosine component of the phosphoproteome and identifies large numbers of tyrosine phosphorylation sites. Peptides containing phosphotyrosine are isolated directly from protease-digested cellular protein extracts with a phosphotyrosine-specific antibody and are identified by tandem mass spectrometry. Applying this approach to several cell systems, including cancer cell lines, shows it can be used to identify activated protein kinases and their phosphorylated substrates without prior knowledge of the signaling networks that are activated, a first step in profiling normal and oncogenic signaling networks.

    Funded by: NCI NIH HHS: 1R43CA101106

    Nature biotechnology 2005;23;1;94-101

  • Alternative splicing in the N-terminus of Alzheimer's presenilin 1.

    Scheper W, Zwart R and Baas F

    Neurogenetics Laboratory, Academic Medical Center, Amsterdam, The Netherlands. w.scheper@amc.uva.nl

    Presenilin 1 (PS1) is mutated in the majority of familial cases of Alzheimer disease (AD). Although it is clear that PS1 is involved in the processing of the amyloid precursor protein (APP), the exact function of PS1 is still elusive. Human presenilin 1 (PS1) is alternatively spliced, resulting in the presence or absence of a four-amino acid motif, VRSQ, in the PS1 N-terminus. In human tissues, both isoforms are expressed. Here we report that mouse and rat only express the longer PS1 isoform. The presence of this motif introduces a potential phosphorylation site for protein kinase C. Because the splice occurs in the region of PS1 that we have previously shown to bind to rabGDI, this might provide a regulatory mechanism for this interaction. Our data show that the -VRSQ isoform binds rabGDI, but the +VRSQ does not. Moreover, mutation of the putatively phosphorylated threonine in PS1 disrupts the binding to rabGDI, showing its importance for the interaction. To our knowledge this is the first study showing a functional difference between PS1 splice variants. The possible consequences for APP processing and the pathogenesis of AD are discussed.

    Neurogenetics 2004;5;4;223-7

  • ExoS Rho GTPase-activating protein activity stimulates reorganization of the actin cytoskeleton through Rho GTPase guanine nucleotide disassociation inhibitor.

    Sun J and Barbieri JT

    Medical College of Wisconsin, Microbiology and Molecular Genetics, Milwaukee, Wisconsin 53226, USA.

    ExoS is a bifunctional Type III cytotoxin of Pseudomonas aeruginosa with N-terminal Rho GTPase-activating protein (RhoGAP) and C-terminal ADP-ribosyltransferase domains. Although the ExoS RhoGAP inactivates Cdc42, Rac, and RhoA in vivo, the relationship between ExoS RhoGAP and the eukaryotic regulators of Rho GTPases is not clear. The present study investigated the roles of Rho GTPase guanine nucleotide disassociation inhibitor (RhoGDI) in the reorganization of actin cytoskeleton mediated by ExoS RhoGAP. A green fluorescent protein-RhoGDI fusion protein was engineered and found to elicit actin reorganization through the inactivation of Rho GTPases. Green fluorescent protein-RhoGDI and ExoS RhoGAP cooperatively stimulated actin reorganization and translocation of Cdc42 from membrane to cytosol, and a RhoGDI mutant, RhoGDI(I177D), that is defective in extracting Rho GTPases off the membrane inhibited the actions of RhoGDI and ExoS RhoGAP on the translocation of Cdc42 from membrane to cytosol. A human RhoGDI small interfering RNA was transfected into HeLa cells to knock down 90% of the endogenous RhoGDI expression. HeLa cells with knockdown RhoGDI were resistant to the reorganization of the actin cytoskeleton elicited by type III-delivered ExoS RhoGAP. This indicates that ExoS RhoGAP and RhoGDI function in series to inactivate Rho GTPases, in which RhoGDI extracting GDP-bound Rho GTPases off the membrane and sequestering them in cytosol is the rate-limiting step in Rho GTPase inactivation. A eukaryotic GTPase-activating protein, p50RhoGAP, showed a similar cooperativity with RhoGDI on actin reorganization, suggesting that ExoS RhoGAP functions as a molecular mimic of eukaryotic RhoGAPs to inactivate Rho GTPases through RhoGDI.

    Funded by: NIAID NIH HHS: AI-030162

    The Journal of biological chemistry 2004;279;41;42936-44

  • The status, quality, and expansion of the NIH full-length cDNA project: the Mammalian Gene Collection (MGC).

    Gerhard DS, Wagner L, Feingold EA, Shenmen CM, Grouse LH, Schuler G, Klein SL, Old S, Rasooly R, Good P, Guyer M, Peck AM, Derge JG, Lipman D, Collins FS, Jang W, Sherry S, Feolo M, Misquitta L, Lee E, Rotmistrovsky K, Greenhut SF, Schaefer CF, Buetow K, Bonner TI, Haussler D, Kent J, Kiekhaus M, Furey T, Brent M, Prange C, Schreiber K, Shapiro N, Bhat NK, Hopkins RF, Hsie F, Driscoll T, Soares MB, Casavant TL, Scheetz TE, Brown-stein MJ, Usdin TB, Toshiyuki S, Carninci P, Piao Y, Dudekula DB, Ko MS, Kawakami K, Suzuki Y, Sugano S, Gruber CE, Smith MR, Simmons B, Moore T, Waterman R, Johnson SL, Ruan Y, Wei CL, Mathavan S, Gunaratne PH, Wu J, Garcia AM, Hulyk SW, Fuh E, Yuan Y, Sneed A, Kowis C, Hodgson A, Muzny DM, McPherson J, Gibbs RA, Fahey J, Helton E, Ketteman M, Madan A, Rodrigues S, Sanchez A, Whiting M, Madari A, Young AC, Wetherby KD, Granite SJ, Kwong PN, Brinkley CP, Pearson RL, Bouffard GG, Blakesly RW, Green ED, Dickson MC, Rodriguez AC, Grimwood J, Schmutz J, Myers RM, Butterfield YS, Griffith M, Griffith OL, Krzywinski MI, Liao N, Morin R, Morrin R, Palmquist D, Petrescu AS, Skalska U, Smailus DE, Stott JM, Schnerch A, Schein JE, Jones SJ, Holt RA, Baross A, Marra MA, Clifton S, Makowski KA, Bosak S, Malek J and MGC Project Team

    The National Institutes of Health's Mammalian Gene Collection (MGC) project was designed to generate and sequence a publicly accessible cDNA resource containing a complete open reading frame (ORF) for every human and mouse gene. The project initially used a random strategy to select clones from a large number of cDNA libraries from diverse tissues. Candidate clones were chosen based on 5'-EST sequences, and then fully sequenced to high accuracy and analyzed by algorithms developed for this project. Currently, more than 11,000 human and 10,000 mouse genes are represented in MGC by at least one clone with a full ORF. The random selection approach is now reaching a saturation point, and a transition to protocols targeted at the missing transcripts is now required to complete the mouse and human collections. Comparison of the sequence of the MGC clones to reference genome sequences reveals that most cDNA clones are of very high sequence quality, although it is likely that some cDNAs may carry missense variants as a consequence of experimental artifact, such as PCR, cloning, or reverse transcriptase errors. Recently, a rat cDNA component was added to the project, and ongoing frog (Xenopus) and zebrafish (Danio) cDNA projects were expanded to take advantage of the high-throughput MGC pipeline.

    Funded by: PHS HHS: N01-C0-12400

    Genome research 2004;14;10B;2121-7

  • From ORFeome to biology: a functional genomics pipeline.

    Wiemann S, Arlt D, Huber W, Wellenreuther R, Schleeger S, Mehrle A, Bechtel S, Sauermann M, Korf U, Pepperkok R, Sültmann H and Poustka A

    Molecular Genome Analysis, German Cancer Research Center, 69120 Heidelberg, Germany. s.wiemann@dkfz.de

    As several model genomes have been sequenced, the elucidation of protein function is the next challenge toward the understanding of biological processes in health and disease. We have generated a human ORFeome resource and established a functional genomics and proteomics analysis pipeline to address the major topics in the post-genome-sequencing era: the identification of human genes and splice forms, and the determination of protein localization, activity, and interaction. Combined with the understanding of when and where gene products are expressed in normal and diseased conditions, we create information that is essential for understanding the interplay of genes and proteins in the complex biological network. We have implemented bioinformatics tools and databases that are suitable to store, analyze, and integrate the different types of data from high-throughput experiments and to include further annotation that is based on external information. All information is presented in a Web database (http://www.dkfz.de/LIFEdb). It is exploited for the identification of disease-relevant genes and proteins for diagnosis and therapy.

    Genome research 2004;14;10B;2136-44

  • Complete sequencing and characterization of 21,243 full-length human cDNAs.

    Ota T, Suzuki Y, Nishikawa T, Otsuki T, Sugiyama T, Irie R, Wakamatsu A, Hayashi K, Sato H, Nagai K, Kimura K, Makita H, Sekine M, Obayashi M, Nishi T, Shibahara T, Tanaka T, Ishii S, Yamamoto J, Saito K, Kawai Y, Isono Y, Nakamura Y, Nagahari K, Murakami K, Yasuda T, Iwayanagi T, Wagatsuma M, Shiratori A, Sudo H, Hosoiri T, Kaku Y, Kodaira H, Kondo H, Sugawara M, Takahashi M, Kanda K, Yokoi T, Furuya T, Kikkawa E, Omura Y, Abe K, Kamihara K, Katsuta N, Sato K, Tanikawa M, Yamazaki M, Ninomiya K, Ishibashi T, Yamashita H, Murakawa K, Fujimori K, Tanai H, Kimata M, Watanabe M, Hiraoka S, Chiba Y, Ishida S, Ono Y, Takiguchi S, Watanabe S, Yosida M, Hotuta T, Kusano J, Kanehori K, Takahashi-Fujii A, Hara H, Tanase TO, Nomura Y, Togiya S, Komai F, Hara R, Takeuchi K, Arita M, Imose N, Musashino K, Yuuki H, Oshima A, Sasaki N, Aotsuka S, Yoshikawa Y, Matsunawa H, Ichihara T, Shiohata N, Sano S, Moriya S, Momiyama H, Satoh N, Takami S, Terashima Y, Suzuki O, Nakagawa S, Senoh A, Mizoguchi H, Goto Y, Shimizu F, Wakebe H, Hishigaki H, Watanabe T, Sugiyama A, Takemoto M, Kawakami B, Yamazaki M, Watanabe K, Kumagai A, Itakura S, Fukuzumi Y, Fujimori Y, Komiyama M, Tashiro H, Tanigami A, Fujiwara T, Ono T, Yamada K, Fujii Y, Ozaki K, Hirao M, Ohmori Y, Kawabata A, Hikiji T, Kobatake N, Inagaki H, Ikema Y, Okamoto S, Okitani R, Kawakami T, Noguchi S, Itoh T, Shigeta K, Senba T, Matsumura K, Nakajima Y, Mizuno T, Morinaga M, Sasaki M, Togashi T, Oyama M, Hata H, Watanabe M, Komatsu T, Mizushima-Sugano J, Satoh T, Shirai Y, Takahashi Y, Nakagawa K, Okumura K, Nagase T, Nomura N, Kikuchi H, Masuho Y, Yamashita R, Nakai K, Yada T, Nakamura Y, Ohara O, Isogai T and Sugano S

    Helix Research Institute, 1532-3 Yana, Kisarazu, Chiba 292-0812, Japan.

    As a base for human transcriptome and functional genomics, we created the "full-length long Japan" (FLJ) collection of sequenced human cDNAs. We determined the entire sequence of 21,243 selected clones and found that 14,490 cDNAs (10,897 clusters) were unique to the FLJ collection. About half of them (5,416) seemed to be protein-coding. Of those, 1,999 clusters had not been predicted by computational methods. The distribution of GC content of nonpredicted cDNAs had a peak at approximately 58% compared with a peak at approximately 42%for predicted cDNAs. Thus, there seems to be a slight bias against GC-rich transcripts in current gene prediction procedures. The rest of the cDNAs unique to the FLJ collection (5,481) contained no obvious open reading frames (ORFs) and thus are candidate noncoding RNAs. About one-fourth of them (1,378) showed a clear pattern of splicing. The distribution of GC content of noncoding cDNAs was narrow and had a peak at approximately 42%, relatively low compared with that of protein-coding cDNAs.

    Nature genetics 2004;36;1;40-5

  • Gene diversity patterns at 10 X-chromosomal loci in humans and chimpanzees.

    Kitano T, Schwarz C, Nickel B and Pääbo S

    Department of Evolutionary Genetics, Max-Planck-Institute for Evolutionary Anthropology, Leipzig, Germany.

    We have investigated the pattern and extent of nucleotide diversity in 10 X-chromosomal genes where mutations are known to cause mental retardation in humans. For each gene, we sequenced the entire coding region from cDNA in humans, chimpanzees, and orangutans, as well as about 3 kb of genomic DNA in 20 humans sampled worldwide and in 10 chimpanzees representing two "subspecies." Overall nucleotide diversity in these genes is about twofold lower in humans than in chimpanzees, and nucleotide diversity within and between species is low, suggesting that a high level of functional constraint acts on these genes. Strikingly, we find that a summary of the allele frequency spectrum is significantly correlated in humans and chimpanzees, perhaps reflecting very similar levels of constraint at these genes in the two species. A possible exception is FMR2, which shows a higher number of nonsynonymous than synonymous substitutions on the human lineage, suggesting the action of positive selection.

    Molecular biology and evolution 2003;20;8;1281-9

  • Membrane targeting of Rab GTPases is influenced by the prenylation motif.

    Gomes AQ, Ali BR, Ramalho JS, Godfrey RF, Barral DC, Hume AN and Seabra MC

    Cell and Molecular Biology, Division of Biomedical Sciences, Faculty of Medicine, Imperial College, London SW7 2AZ, United Kingdom.

    Rab GTPases are regulators of membrane traffic. Rabs specifically associate with target membranes via the attachment of (usually) two geranylgeranyl groups in a reaction involving Rab escort protein and Rab geranylgeranyl transferase. In contrast, related GTPases are singly prenylated by CAAX prenyl transferases. We report that di-geranylgeranyl modification is important for targeting of Rab5a and Rab27a to endosomes and melanosomes, respectively. Transient expression of EGFP-Rab5 mutants containing two prenylatable cysteines (CGC, CC, CCQNI, and CCA) in HeLa cells did not affect endosomal targeting or function, whereas mono-cysteine mutants (CSLG, CVLL, or CVIM) were mistargeted to the endoplasmic reticulum (ER) and were nonfunctional. Similarly, Rab27aCVLL mutant is also mistargeted to the ER and transgenic expression on a Rab27a null background (Rab27aash) did not rescue the coat color phenotype, suggesting that Rab27aCVLL is not functional in vivo. CAAX prenyl transferase inhibition and temperature-shift experiments further suggest that Rabs, singly or doubly modified are recruited to membranes via a Rab escort protein/Rab geranylgeranyl transferase-dependent mechanism that is distinct from the insertion of CAAX-containing GTPases. Finally, we show that both singly and doubly modified Rabs are extracted from membranes by RabGDIalpha and propose that the mistargeting of Rabs to the ER results from loss of targeting information.

    Molecular biology of the cell 2003;14;5;1882-99

  • Defects in cytokinesis, actin reorganization and the contractile vacuole in cells deficient in RhoGDI.

    Rivero F, Illenberger D, Somesh BP, Dislich H, Adam N and Meyer AK

    Institut für Biochemie I, Medizinische Fakultät, University of Cologne, Joseph-Stelzmann-Strasse 52, D-50931 Köln, Germany. francisco.rivero@uni-koeln.de

    Rho GDP-dissociation inhibitors (RhoGDIs) modulate the cycling of Rho GTPases between active GTP-bound and inactive GDP-bound states. We identified two RhoGDI homologues in DICTYOSTELIUM: GDI1 shares 51-58% similarity to RhoGDIs from diverse species. GDI2 is more divergent (40-44% similarity) and lacks the N-terminal regulatory arm characteristic for RhoGDI proteins. Both are cytosolic proteins and do not relocalize upon reorganization of the actin cytoskeleton. Using a two-hybrid approach, we identified Rac1a/1b/1c, RacB, RacC and RacE as interacting partners for GDI1. Cells lacking GDI1 are multinucleate, grow slowly and display a moderate pinocytosis defect, but rates of phagocytosis are unaffected. Mutant cells present prominent actin-rich protrusions, and large vacuoles that are continuous with the contractile vacuole system. The actin polymerization response upon stimulation with cAMP was reduced, but the motile behavior toward the chemoattractant was unaffected. Our results indicate that GDI1 plays a central role in the regulation of signal transduction cascades mediated by Rho GTPases.

    The EMBO journal 2002;21;17;4539-49

  • The hematopoiesis-specific GTP-binding protein RhoH is GTPase deficient and modulates activities of other Rho GTPases by an inhibitory function.

    Li X, Bu X, Lu B, Avraham H, Flavell RA and Lim B

    Division of Hematology and Oncology, Cancer Biology Program, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02115, USA.

    The Rho subfamily of small GTP-binding proteins mediates many fundamental cellular functions. The commonly studied members (Rho, Rac, and CDC42) regulate actin reorganization, affecting diverse cellular responses, including adhesion, cytokinesis, and motility. Another major function of the Rho GTPases is their role in regulating transcriptional factors and nuclear signaling. RhoH is encoded by a hematopoiesis-specific Rho-related gene recently identified in a fusion transcript with bcl6 in lymphoma cell lines. Significantly, translocations and a high frequency of RhoH mutation have been detected in primary lymphoma cells. We show here that RhoH functions differently from other Rho GTPases. RhoH exerts no significant effect on actin reorganization. However, RhoH is a potent inhibitor of the activation of NFkappaB and p38 by other Rho GTPases. This property, together with the differential expression of RhoH in the Th1 subset of T cells, suggests a role for RhoH in the functional differentiation of T cells. RhoH has different amino acids in two highly conserved residues critical for GTPase activity. Consequently, RhoH is GTPase deficient, remaining in a GTP-bound activated state without cycling. Reduction of RhoH levels in T cells augments the response to Rac activation. Furthermore, RhoH is dramatically down regulated after phorbol myristate acetate treatment and in Th1 cells after activation by anti-CD3. Hence, a mechanism for regulation of RhoH function is likely to exist at the transcriptional level. The inhibitory function of RhoH supports a model in which Rho GTPases with opposing functions may compete to modulate the final outcome of a particular GTPase-activated pathway.

    Funded by: NIDDK NIH HHS: R01DK-47535, R01DK-54417

    Molecular and cellular biology 2002;22;4;1158-71

  • Rab3B in human platelet is membrane bound and interacts with Ca(2+)/calmodulin.

    Sidhu RS and Bhullar RP

    Department of Oral Biology, University of Manitoba, Winnipeg, Manitoba, R3E 0W2, Canada.

    The subcellular distribution of Rab3B in fresh and aged platelets was determined and majority of the protein was localized with the particulate fraction with only a minor amount detected in the cytosol. Rab3B was pulled out from platelet particulate fraction with GST-RabGDI-alpha fusion protein. Using GST-Rab3B in in vitro pull-down experiments, the binding of calmodulin from platelet cytosol to Rab3B was demonstrated. In the reverse experiment, binding of Rab3B from platelet particulate and cytosolic fractions to Sepharose-CaM beads was also observed. The interaction between Rab3B and calmodulin was Ca(2+)-dependent but independent of the guanine nucleotide status of Rab3B. These findings provide evidence that Rab3B is primarily localized with the particulate fraction and that Ca(2+)/calmodulin could regulate function of this GTPase in the platelet.

    Biochemical and biophysical research communications 2001;289;5;1039-43

  • RhoGDI-binding-defective mutant of Cdc42Hs targets to membranes and activates filopodia formation but does not cycle with the cytosol of mammalian cells.

    Gibson RM and Wilson-Delfosse AL

    Department of Pharmacology, Case Western Reserve University, School of Medicine, 10900 Euclid Avenue, Cleveland, OH 44106-4965, USA.

    We have identified a mutant of the human G-protein Cdc42Hs, R66E, that fails to form a detectable complex with the GDP-dissociation inhibitor RhoGDI in cell-free systems or in intact cells. This point mutant is prenylated, binds guanine nucleotide and interacts with GTPase-activating protein in a manner indistinguishable from wild-type Cdc42Hs. Immunofluorescence localization studies revealed that this RhoGDI-binding-defective mutant is found predominantly in the Golgi apparatus, with a staining pattern similar to that of the wild-type protein. However, unlike wild-type Cdc42Hs, which is distributed in both the microsomal membrane and cytosolic fractions, studies using differential centrifugation show that prenylated R66E Cdc42Hs is found exclusively in association with lipid bilayers. Additionally, whereas the overexpression of RhoGDI results in an apparent translocation of wild-type Cdc42Hs from the Golgi apparatus into the cytosol, identical RhoGDI-overexpression conditions do not alter the Golgi localization of the R66E mutant. Furthermore, overexpression of this RhoGDI-binding-defective mutant of Cdc42Hs seems to activate redistribution of the actin cytoskeleton and filopodia formation in fibroblasts in a manner indistinguishable from the wild-type protein. Taken together, these results suggest that the interaction of Cdc42Hs with RhoGDI is not essential for proper membrane targeting of nascent prenylated Cdc42Hs in mammalian cells; neither is this interaction an essential part of the mechanism by which Cdc42Hs activates filopodia formation. However, it does seem that redistribution of Cdc42Hs to the cytosolic compartment is absolutely dependent on RhoGDI interaction.

    The Biochemical journal 2001;359;Pt 2;285-94

  • DNA cloning using in vitro site-specific recombination.

    Hartley JL, Temple GF and Brasch MA

    Life Technologies, Inc., Rockville, Maryland 20850, USA. jhartley@lifetech.com

    As a result of numerous genome sequencing projects, large numbers of candidate open reading frames are being identified, many of which have no known function. Analysis of these genes typically involves the transfer of DNA segments into a variety of vector backgrounds for protein expression and functional analysis. We describe a method called recombinational cloning that uses in vitro site-specific recombination to accomplish the directional cloning of PCR products and the subsequent automatic subcloning of the DNA segment into new vector backbones at high efficiency. Numerous DNA segments can be transferred in parallel into many different vector backgrounds, providing an approach to high-throughput, in-depth functional analysis of genes and rapid optimization of protein expression. The resulting subclones maintain orientation and reading frame register, allowing amino- and carboxy-terminal translation fusions to be generated. In this paper, we outline the concepts of this approach and provide several examples that highlight some of its potential.

    Genome research 2000;10;11;1788-95

  • Systematic subcellular localization of novel proteins identified by large-scale cDNA sequencing.

    Simpson JC, Wellenreuther R, Poustka A, Pepperkok R and Wiemann S

    Department of Cell Biology and Biophysics, EMBL Heidelberg, Germany.

    As a first step towards a more comprehensive functional characterization of cDNAs than bioinformatic analysis, which can only make functional predictions for about half of the cDNAs sequenced, we have developed and tested a strategy that allows their systematic and fast subcellular localization. We have used a novel cloning technology to rapidly generate N- and C-terminal green fluorescent protein fusions of cDNAs to examine the intracellular localizations of > 100 expressed fusion proteins in living cells. The entire analysis is suitable for automation, which will be important for scaling up throughput. For > 80% of these new proteins a clear intracellular localization to known structures or organelles could be determined. For the cDNAs where bioinformatic analyses were able to predict possible identities, the localization was able to support these predictions in 75% of cases. For those cDNAs where no homologies could be predicted, the localization data represent the first information.

    EMBO reports 2000;1;3;287-92

  • PRA1 inhibits the extraction of membrane-bound rab GTPase by GDI1.

    Hutt DM, Da-Silva LF, Chang LH, Prosser DC and Ngsee JK

    Department of Biochemistry, University of Ottawa, Loeb Health Research Institute, Ottawa, Ontario K1Y 4E9, Canada.

    Rab is a family of small Ras-like GTPases regulating intracellular vesicle transport. We have previously reported that prenylated Rab acceptor or PRA1 interacts with Rab GTPases and vesicle-associated membrane protein (VAMP2). Structural prediction programs suggest that PRA1, with its two extensive hydrophobic domains, is likely to be an integral membrane protein. However, subcellular fractionation and immunocytochemical analyses indicated that PRA1 is localized both in the cytosol and tightly associated with the membrane compartment. The membrane-bound form can be partially extracted with physiological buffer and urea, suggesting that PRA1 is an extrinsic membrane protein. Deletion of the carboxyl-terminal domain resulted in a protein that behaved as an integral membrane protein, indicating that this domain plays an essential role in maintaining PRA1 in a soluble state. PRA1 can also bind weakly to GDP dissociation inhibitor (GDI), a protein involved in the solubilization of membrane-bound Rab GTPases. Addition of PRA1 inhibited the extraction of membrane-bound Rab3A by GDI, suggesting that membrane localization of Rab GTPases is dependent on the opposing action of PRA1 and GDI. The binding of Rab and VAMP2 to PRA1 is mutually exclusive such that Rab3A can displace VAMP2 in a preformed VAMP2-PRA1 complex.

    The Journal of biological chemistry 2000;275;24;18511-9

  • Non-specific X-linked semidominant mental retardation by mutations in a Rab GDP-dissociation inhibitor.

    Bienvenu T, des Portes V, Saint Martin A, McDonell N, Billuart P, Carrié A, Vinet MC, Couvert P, Toniolo D, Ropers HH, Moraine C, van Bokhoven H, Fryns JP, Kahn A, Beldjord C and Chelly J

    INSERM U129, Institut Cochin de Génétique Moléculaire, 24 rue du Faubourg Saint-Jacques, 75014 Paris, France. bienvenu@cochin.inserm.fr

    Non-specific X-linked mental retardation (MRX) is a very common disorder which affects approximately 1 in 600 males. Despite this high frequency, little is known about the molecular defects underlying this disorder, mainly because of the clinical and genetic heterogeneity which is evident from linkage studies. Recently, a collaborative study using the candidate gene approach demonstrated the presence of mutations in GDIalpha, a Rab GDP-dissociation inhibitor encoded by a gene localized in Xq28, associated with non-specific mental retardation. GDIalpha is mainly a brain-specific protein that plays a critical role in the recycling of Rab GTPases involved in membrane vesicular transport. The study presented here was designed to assess the prevalence of mutations in the GDIalpha in mentally retarded patients and to discuss the clinical phenotypes observed in affected individuals. Mutation screening of the whole coding region of the GDIalpha gene, using a combination of denaturing gradient gel electrophoresis and direct sequencing, was carried out in 164 patients found negative for expansions across the FRAXA GCC repeat. In addition to the nonsense mutation recently reported in MRX48, we have identified a novel missense mutation in exon 11 of the GDIalpha gene in one familial form of non-specific mental retardation. In this family (family R), all affected males show moderate to severe mental retardation, and the X-linked semidominant inheritance is strongly suggested by the severe phenotypes in males with respect to mildly affected females or unaffected obligatory carriers. This study showed that the prevalence of GDIalpha mutations in non-specific mental retardation could be estimated to be 0.5-1%, and molecular diagnosis and genetic counselling in some cases of non-specific mental handicap can now be provided.

    Funded by: Telethon: E.0297

    Human molecular genetics 1998;7;8;1311-5

  • Evaluation of two X chromosomal candidate genes for Rett syndrome: glutamate dehydrogenase-2 (GLUD2) and rab GDP-dissociation inhibitor (GDI1).

    Wan M and Francke U

    Department of Genetics, Stanford University School of Medicine, California, USA.

    The most likely cause of the Rett syndrome (RTT) is an X-linked dominant mutation lethal in hemizygous males. Previous exclusion mapping studies have identified putative regions for the RTT gene on the X chromosome. In the present study, we evaluated two candidate genes, glutamate dehydrogenase-2 (GLUD2) and rab GDP-dissociation inhibitor (GDI1/XAP-4), chosen because of their expression patterns and functions in the central nervous system and their location in the nonexcluded region of Xq. The intronless gene GLUD2, located in Xq25 and expressed in neuronal and testicular tissues, is involved in the metabolism of glutamate, a neurotransmitter reported to be elevated in the spinal fluid of RTT individuals. The GLUD2 gene was screened for mutations by Southern hybridization and by direct sequencing of polymerase chain reaction (PCR) products. The GDI1 gene in Xq28, also known as RABGDIA or XAP-4, encodes a human GDI that is expressed predominantly in neuronal and sensory tissues. All 11 exons and splice junctions of the GDI1 gene were PCR-amplified and sequenced directly or screened by single-strand conformation analysis. No mutation in either of these two genes was found in 22 RTT patients. Therefore, GLUD2 and GDI1 can be excluded as candidate genes for this syndrome.

    Funded by: NICHD NIH HHS: HD24234

    American journal of medical genetics 1998;78;2;169-72

  • Mutations in GDI1 are responsible for X-linked non-specific mental retardation.

    D'Adamo P, Menegon A, Lo Nigro C, Grasso M, Gulisano M, Tamanini F, Bienvenu T, Gedeon AK, Oostra B, Wu SK, Tandon A, Valtorta F, Balch WE, Chelly J and Toniolo D

    Institute of Genetics Biochemistry and Evolution, CNR, Pavia, Italy.

    Rab GDP-dissociation inhibitors (GDI) are evolutionarily conserved proteins that play an essential role in the recycling of Rab GTPases required for vesicular transport through the secretory pathway. We have found mutations in the GDI1 gene (which encodes uGDI) in two families affected with X-linked non-specific mental retardation. One of the mutations caused a non-conservative substitution (L92P) which reduced binding and recycling of RAB3A, the second was a null mutation. Our results show that both functional and developmental alterations in the neuron may account for the severe impairment of learning abilities as a consequence of mutations in GDI1, emphasizing its critical role in development of human intellectual and learning abilities.

    Funded by: NEI NIH HHS: EY11606; NIGMS NIH HHS: GM33301; Telethon: E.0297

    Nature genetics 1998;19;2;134-9

  • Differential properties of D4/LyGDI versus RhoGDI: phosphorylation and rho GTPase selectivity.

    Gorvel JP, Chang TC, Boretto J, Azuma T and Chavrier P

    Centre d'Immunologie INSERM-CNRS de Marseille-Luminy, France.

    RhoA/B/C and CDC42/Rac, which form two subgroups of the rho guanosine triphosphatase (GTPase) family, regulate various aspects of actin cytoskeleton organisation. In cytosol, guanosine diphosphate (GDP) dissociation inhibitor (GDI) interacts with and maintains rho GTPases in their inactive GDP-bound form. RhoGDI is a ubiquitously expressed GDI, whereas D4/LyGDI is hematopoietic cell-specific and 10-fold less potent than RhoGDI in binding to and regulating rho GTPases. We have combined microanalytical liquid chromatography with the use of specific antibodies in order to separate D4/LyGDI and RhoDGI-complexes from the cytosol of U937 cells and to demonstrate that the two GDIs associate with different rho protein partners. RhoGDI can form a complex with CDC42Hs, RhoA, Rac1 and Rac2, while none of these GTPases was found to interact with D4/LyGDI. In addition, we found that stimulation of U937 cells with phorbol ester leads to phosphorylation of D4/LyGDI. Our results suggest that LyGDI forms complexes with specific rho GTPases expressed in hematopoietic cells where it may regulate specific pathways.

    FEBS letters 1998;422;2;269-73

  • A gene for dominant nonspecific X-linked mental retardation is located in Xq28.

    des Portes V, Billuart P, Carrié A, Bachner L, Bienvenu T, Vinet MC, Beldjord C, Ponsot G, Kahn A, Boué J and Chelly J

    INSERM U129-ICGM, Faculté de Médecine Cochin, Paris, France.

    A large family (MRX48) with a nonspecific X-linked mental retardation condition is described. An X-linked semidominant inheritance is suggested by the segregation in three generations of a moderate to severe mental retardation in seven males and by a milder intellectual impairment in two females, without any specific clinical, radiological, or biological feature. Two-point linkage analysis demonstrated significant linkage between the disorder and several markers in Xq28 (maximum LOD score [Zmax] = 2.71 at recombination fraction [theta] = 0); multipoint linkage analyses confirmed the significant linkage with a Zmax of 3.3 at theta = 0, at DXS1684. A recombination event observed with the flanking marker DXS8011 delineates a locus between this marker and the telomere. The approximate length of this locus is 8-9 cM, corresponding to 5.5-6 Mb. In an attempt to explain the variable intellectual impairment in females, we examined X-chromosome inactivation in all females of the family. Inactivation patterns in lymphocytes were random or moderately skewed, and no correlation between the phenotypic status and a specific inactivation pattern was observed. The interval of assignment noted in this family overlaps with five MRX loci previously reported in Xq28.

    American journal of human genetics 1997;60;4;903-9

  • Prenylation of a Rab1B mutant with altered GTPase activity is impaired in cell-free systems but not in intact mammalian cells.

    Wilson AL, Sheridan KM, Erdman RA and Maltese WA

    Weis Center for Research, Geisinger Clinic, Danville, PA 17822-2616, USA.

    Previous studies have reached differing conclusions as to whether or not guanine-nucleotide-dependent conformational changes affect the ability of Rab proteins to undergo post-translational modification by Rab:geranylgeranyltransferase (Rab-GGTase). We now show that the ability of a Rab1B mutant [Q67L (Gln-67-->Leu)] with reduced intrinsic GTPase activity to undergo geranylgeranylation in cell-free assays depends on the guanine nucleotide composition of the system. When GTP is the predominant nucleotide in the assay, Rab1BQ67L is a poor substrate. However, when GDP is present and GTP is omitted, prenylation of the Q67L mutant is comparable with that of the wild-type (WT) protein. These studies, coupled with the poor prenylation of Rab1BWT in the presence of the non-hydrolysable GTP analogue guanosine 5'-[gamma-thio]triphosphate, support the notion that Rab-GGTase prefers substrates in the GDP conformation. When the abilities of Rab1BQ67L and Rab1BWT to undergo prenylation were compared by metabolic labelling of transiently expressed proteins in cultured human 293 cells, we did not observe a decline in prenylation of the mutant protein as predicted on the basis of the cell-free assays. Moreover, the Q67L mutant was comparable with the wild-type Rab1B in its ability to associate with co-expressed Rab GDP dissociation inhibitors in 293 cells. These findings raise the possibility that unidentified proteins present in intact cells may compensate for the reduced intrinsic GTPase activity of the Q67L mutant, allowing a significant proportion of the nascent Rab1BQ67L to assume a GDP conformation. The differential prenylation of Rab1BQ67L in cell-free systems versus intact cells underscores the importance of evaluating the post-translational modification of specific Rab mutants in vivo, where poorly characterized regulatory proteins may have a significant effect on GTPase activity or nucleotide exchange rates.

    Funded by: NCI NIH HHS: CA34569

    The Biochemical journal 1996;318 ( Pt 3);1007-14

  • A gene for nonspecific X-linked mental retardation (MRX41) is located in the distal segment of Xq28.

    Hamel BC, Kremer H, Wesby-van Swaay E, van den Helm B, Smits AP, Oostra BA, Ropers HH and Mariman EC

    Department of Human Genetics, University Hospital, Nijmegen, The Netherlands.

    We report on a family in which nonsyndromal mild to moderate mental retardation segregates as an X-linked trait (MRX41). Two point linkage analysis demonstrated linkage between the disorder and marker DXS3 in Xq21.33 with a lod score of 2.56 at theta = 0.0 and marker DXS1108 in Xq28 with a lod score of 3.82 at theta = 0.0. Multipoint linkage analysis showed that the odds for a location of the gene in Xq28 vs Xq21.33 are 100:1. This is the fourth family with non-specific X-linked mental retardation with Xq28-qter as the most likely gene localization.

    American journal of medical genetics 1996;64;1;131-3

  • Long-range sequence analysis in Xq28: thirteen known and six candidate genes in 219.4 kb of high GC DNA between the RCP/GCP and G6PD loci.

    Chen EY, Zollo M, Mazzarella R, Ciccodicola A, Chen CN, Zuo L, Heiner C, Burough F, Repetto M, Schlessinger D and D'Urso M

    Advanced Center for Genetic Technology, Applied Biosystems Division of Perkin Elmer Corp, Foster City, CA 94404, USA.

    DNA comprising 219 447 bp was sequenced in nine cosmids and verified at > 99.9% precision. Of the standard repetitive elements, 187 Alus make up 20.6% of the sequence, but there were only 27 MERs (2.9%) and 17 L1 fragments (1.6%). This may be characteristic of such high GC (57%) regions. The sequence also includes an 11.3 kb tract duplicated with 99.2% identity at a distance of 38 kb. The region is 80-90% transcribed and 12.5% translated. Thirteen known genes and their exon-intron borders are all accurately predicted at least in part by GRAIL programs, as are six additional genes. From centromere to telomere, the orientation of transcription varies among the first eight genes, then runs centromeric to telomeric for the next five, and is in the opposite sense for the last six. Eighteen of the 19 genes are associated with CpG islands. Two islands are exact copies in the 11.3 kb repeat units, and could thus give rise to double dosage levels of an X-linked gene. Another island is associated with two genes transcribed in opposite directions. From the sequence data, three genes and their exon structure are inferred. One of them, previously associated with HEX2, is shown to be a different gene unrelated to hexokinases; a second gene, previously known by an EST, is plexin, from its 65.5% identity with the Xenopus analog; and a third is a subunit of a vacuolar H-ATPase, and is named VATPS1.

    Funded by: NHGRI NIH HHS: HG00201; Telethon: 417

    Human molecular genetics 1996;5;5;659-68

  • Cloning of a brain-type isoform of human Rab GDI and its expression in human neuroblastoma cell lines and tumor specimens.

    Nishimura N, Goji J, Nakamura H, Orita S, Takai Y and Sano K

    Department of Pediatrics, Kobe University School of Medicine, Japan.

    Rab proteins, a family of Ras-related small GTP-binding proteins, play a key role in regulating intracellular vesicle trafficking. Rab GDP dissociation inhibitor (GDI3) forms a soluble complex with Rab proteins and thereby prevents the exchange of GDP for GTP. Recently, two isoforms of Rab GDI cDNA were isolated from rats and mice. In this study, we have isolated a brain-type isoform of human Rab GDI cDNA and examined its expression in neuroblastoma. We tentatively designate it as human Rab GDI alpha (hu GDI alpha) and another human Rab GDI, as human Rab GDI beta (hu GDI beta). Hu GDI alpha cDNA encodes a protein of 447 amino acids with a deduced molecular weight of 50,200. Northern blot analysis revealed that hu GDI alpha gene is expressed abundantly in the brain but much less in other tissues, while hu GDI beta gene is ubiquitously expressed. All human neuroblastoma cell lines and tumor specimens examined express hu GDI alpha gene to various extents, while a human T cell leukemia cell line, MOLT3, does not. The levels of both hu GDI alpha and beta mRNA were constant in a human neuroblastoma cell line, NB1, during its neuronal differentiation, while Rab3A and neurofilament-L gene expression and the number of neurosecretory granules were elevated at this condition. These results suggest that hu GDI alpha gene expression is not related to the differentiation state of neuronal cells.

    Cancer research 1995;55;22;5445-50

  • Quantitative analysis of the interactions between prenyl Rab9, GDP dissociation inhibitor-alpha, and guanine nucleotides.

    Shapiro AD and Pfeffer SR

    Department of Biochemistry, Stanford University School of Medicine, California 94305-5307, USA.

    Rab9 is a Ras-like GTPase required for the transport of mannose 6-phosphate receptors between late endosomes and the trans Golgi network. Rab9 occurs in the cytosol as a complex with GDP dissociation inhibitor (GDI), which we have shown delivers prenyl Rab9 to late endosomes in a functional form. We report here basal rate constants for guanine nucleotide dissociation and GTP hydrolysis for prenyl Rab9. Both rate constants were influenced in part by the hydrophobic environment of the prenyl group. Guanine nucleotide dissociation and GTP hydrolysis rates were lower in the presence of lipid; detergent stimulated intrinsic nucleotide exchange. GDI-alpha inhibited GDP dissociation from prenyl Rab9 by 2.4-fold. GDI-alpha associated with prenyl Rab9 with a KD of 60 nM in 0.1% Lubrol and 23 nM in 0.02% Lubrol. In 0.1% Lubrol, GDI-alpha inhibited GDP dissociation half maximally at 72 +/- 18 nM, consistent with the KD determinations. These data suggest that GDI-alpha associates with prenyl Rab9 with a KD of < or = 23 nM under physiological conditions. Finally, a previously uncharacterized minor form of GDI-alpha inhibited GDP dissociation from prenyl Rab9 by 1.9-fold and bound prenyl Rab9 with a KD of 67 nM in 0.1% Lubrol.

    Funded by: NIDDK NIH HHS: DK37332

    The Journal of biological chemistry 1995;270;19;11085-90

  • Expression patterns of two human genes coding for different rab GDP-dissociation inhibitors (GDIs), extremely conserved proteins involved in cellular transport.

    Bächner D, Sedlacek Z, Korn B, Hameister H and Poustka A

    Abteilung Medizinische Genetik der Universität, Ulm, Germany.

    We have analysed the expression patterns of two human genes coding for two different rab GDIs, rab GDI alpha/XAP-4 and rab GDI beta, proteins involved in the regulation of vesicle-mediated cellular transport. The gene sequences are extremely conserved in evolution, with substantial homology preserved across three eukaryotic kingdoms. Although the sequence homology between the two human rab GDIs studied is very high, their expression patterns are completely different. The Northern blot analysis and in situ hybridization to sections of mouse embryos and postnatal tissues have revealed that the rab GDI alpha/XAP-4 is expressed predominantly in neural and sensory tissues and may thus serve a specific function in neural signal transmission. In contrast to rab GDI alpha/XAP-4, the human rab GDI beta is expressed ubiquitously.

    Human molecular genetics 1995;4;4;701-8

  • Evolutionary conservation and genomic organization of XAP-4, an Xq28 located gene coding for a human rab GDP-dissociation inhibitor (GDI).

    Sedlacek Z, Konecki DS, Korn B, Klauck SM and Poustka A

    Deutsches Krebsforschungszentrum, Heidelberg, Germany.

    After the development of efficient methods for the construction of transcription maps of defined genomic regions, the rate-limiting step in the analysis of the coding potentials of these regions is the elucidation of function of the novel genes and the examination of their possible involvement in hereditary diseases localized to the region. This can be greatly facilitated by the detection of sequence homology to a gene of known function. XAP-4 is one of the genes identified in the G6PD region of the human Xq28 by direct cDNA selection. The rapid assembly of this gene and the determination of its function was possible because of its sequence homology with the bovine smg p25A/rab3A GDP dissociation inhibitor (GDI). Sequence comparison with other GDIs in the databases has revealed that XAP-4 belongs to one of at least two distinct classes of mammalian rab GDIs. The rab GDIs, which play an important role in the regulation of cellular transport, are highly evolutionarily conserved, as are several other genes identified in the neighborhood of XAP-4. This genomic region is very gene dense, and all the cDNA clones from the approximately 2.5-kb-long transcript of XAP-4 map to a single 7.5-kb genomic EcoRI fragment. The genomic organization of XAP-4 has been examined to determine the distribution of the exonic sequences within this short segment of genomic DNA. It was found that, similar to several other genes from the region, XAP-4 is split into exons of average size, which are interrupted by very short introns.

    Mammalian genome : official journal of the International Mammalian Genome Society 1994;5;10;633-9

  • Determination of structural requirements for the interaction of Rab6 with RabGDI and Rab geranylgeranyltransferase.

    Beranger F, Cadwallader K, Porfiri E, Powers S, Evans T, de Gunzburg J and Hancock JF

    INSERM Unite 248, Paris.

    The importance of geranylgeranylation to the interaction of Rab proteins with RabGDI was investigated with a set of Rab6 mutants post-translationally modified by all known C-terminal lipid combinations. Rab6 proteins geranylgeranylated on CXC or CC motifs were found to be significantly better substrates for membrane extraction by RabGDI than either Rab6 proteins geranylgeranylated on CAAL motifs or Rab6 proteins that were farnesylated and palmitoylated. The methylation status of the CXC motif did not significantly affect interaction of wild type Rab6 with RabGDI. Rab6 protein sequences required for RabGDI interaction were then identified. Consistent with the significant homology between Rab-GDI and the Rab escort protein, a subunit of Rab geranylgeranyltransferase (RabGGTase), we show that there is an overlap between Rab6 motifs required for RabGDI binding and RabGGTase processing. The effector domain, loop3/beta 3 and the hypervariable region of Rab6 are all required for RabGDI binding, whereas loop3/beta 3 and the hypervariable region but not the effector domain are required for efficient processing of Rab6 by RabGGTase. Interestingly, however, loop3/beta 3 of Rab6 when introduced into H-Ras is sufficient to allow some in vivo processing of a C-terminal CSC motif.

    The Journal of biological chemistry 1994;269;18;13637-43

  • Cloning, characterization, and expression of a novel GDP dissociation inhibitor isoform from skeletal muscle.

    Shisheva A, Südhof TC and Czech MP

    Program in Molecular Medicine, University of Massachusetts Medical Center, Worcester 01605.

    Cellular mechanisms for controlling membrane trafficking appear to involve small GTP-binding proteins such as the Rab proteins. Rab function is regulated by GDP dissociation inhibitor (GDI), which releases Rab proteins from membranes and inhibits GDP dissociation. Here we report the isolation of a full-length cDNA encoding a novel GDI isoform of 445 amino acids (GDI-2) with a deduced molecular weight of 50,649 from mouse skeletal muscle. Full-length and partial cDNA clones encoding a previously reported GDI protein (GDI-1) were also isolated from cDNA libraries prepared from rat brain and mouse skeletal muscle, respectively. The degree of deduced amino acid sequence identity between mouse GDI-2 and our mouse GDI-1 cDNA clone is 86%. Northern (RNA blot) analysis revealed that in human tissues, both GDI-1 and GDI-2 transcripts were abundant in brain, skeletal muscle, and pancreas but were weakly expressed in heart and liver. GDI-1 mRNA was expressed in kidney, whereas GDI-2 was almost absent, while in lung the relative amounts of these mRNA species were reversed. Specific antibodies against mouse GDI-1 and GDI-2 based on unique peptide sequences in the proteins were raised. Differentiation of 3T3-L1 fibroblasts into highly insulin-responsive adipocytes was accompanied by large increases in both mRNA and protein levels of GDI-1 and GDI-2. GDI-1 and GDI-2 expressed as glutathione S-transferase fusion proteins were both able to solubilize the membrane-bound forms of Rab4 and Rab5 in a GDP/GTP-dependent manner. Taken together, these data demonstrate that the protein products of at least two genes regulate the membrane dynamics of Rab proteins in mice.

    Funded by: NIDDK NIH HHS: DK30898

    Molecular and cellular biology 1994;14;5;3459-68

  • Construction of a transcription map of a 300 kb region around the human G6PD locus by direct cDNA selection.

    Sedlacek Z, Korn B, Konecki DS, Siebenhaar R, Coy JF, Kioschis P and Poustka A

    Deutsches Krebsforschungszentrum, Heidelberg, Germany.

    A transcription map covering a 300 kb region around the G6PD gene in the human Xq28 region was constructed by the direct cDNA selection method and the analysis of the resulting region-specific enriched cDNA sublibrary. Seven new genes and two loci of endogenous retrovirus HERV-K were identified. The distribution of the genes across the region is strongly non-uniform and follows the non-uniform distribution of GpG islands in the area. While one of the novel genes was found to be highly homologous to bovine smg p25A GDP-dissociation inhibitor, the remaining genes did not detect any homology to known genes. The analysis of region-specific cDNA sublibraries represents a simple, rapid and efficient tool for the generation of a regional transcription map.

    Human molecular genetics 1993;2;11;1865-9

  • A novel role for RhoGDI as an inhibitor of GAP proteins.

    Hancock JF and Hall A

    ONYX Pharmaceuticals, Richmond, CA 94806.

    RhoGDI inhibits guanine nucleotide dissociation from post-translationally processed Rho and Rac proteins but its biochemical role in vivo is unknown. We show here that N-terminal effector site mutations in the Rac protein do not compromise its interaction with RhoGDI and that, whilst geranylgeranylation and -AAX proteolysis of the C-terminal CAAX motif of Rac1 and RhoA are required for efficient interaction with RhoGDI, methylesterification of the C-terminal cysteine residue is not required. In vitro, RhoGDI can form stable complexes with Rho and Rac proteins in both the GTP and GDP bound states. Furthermore the Rac-GTP--RhoGDI complex is resistent to the action of recombinant RhoGAP and recombinant BCR. Thus GDI, by complexing with Rac-GTP and preventing GAP stimulated GTP hydrolysis, may allow transit of the activated form of the Rac protein between physically separated activator and effector proteins in the cell.

    The EMBO journal 1993;12;5;1915-21

  • Microsequences of 145 proteins recorded in the two-dimensional gel protein database of normal human epidermal keratinocytes.

    Rasmussen HH, van Damme J, Puype M, Gesser B, Celis JE and Vandekerckhove J

    Institute of Medical Biochemistry, Aarhus University, Denmark.

    Microsequencing of proteins recovered from two-dimensional (2-D) gels is being used systematically to identify proteins in the master human keratinocyte 2-D gel database. To date, about 250 protein spots recorded in human 2-D gel databases have been microsequenced and, of these, 145 are recorded in the keratinocyte database under the entry partial amino acid sequence. Coomassie Brilliant Blue-stained protein spots cut from several (up to 40) dry gels were concentrated by elution-concentration gel electrophoresis, electroblotted onto PVDF membranes and digested in situ with trypsin. Eluting peptides were separated by reversed-phase HPLC, collected individually and sequenced. Computer search using the FASTA and TFASTA programs from Genetics Computer Group indicated that 110 of the microsequenced polypeptides shared significant similarity with proteins contained in the PIR, Mipsx or GenEMBL databases. Only 35 polypeptides corresponded to hitherto unknown proteins. Peptide sequences of all 145 proteins are listed together with their coordinates (apparent molecular weight and pI) in the keratinocyte database.

    Electrophoresis 1992;13;12;960-9

  • Molecular cloning and characterization of a novel type of regulatory protein (GDI) for smg p25A, a ras p21-like GTP-binding protein.

    Matsui Y, Kikuchi A, Araki S, Hata Y, Kondo J, Teranishi Y and Takai Y

    Research Center, Mitsubishi Kasei Corporation, Yokohama, Japan.

    We recently purified to near homogeneity a novel type of regulatory protein for smg p25A, a ras p21-like GTP-binding protein, from bovine brain cytosol. This regulatory protein, named smg p25A GDP dissociation inhibitor (GDI), regulates the GDP-GTP exchange reaction of smg p25A by inhibiting dissociation of GDP from and subsequent binding of GTP to it. In the present studies, we isolated and sequenced the cDNA of smg p25A GDI from a bovine brain cDNA library by using an oligonucleotide probe designed from the partial amino acid sequence of purified smg p25A GDI. The cDNA has an open reading frame that encodes a protein of 447 amino acids with a calculated Mr of 50,565. This Mr is similar to those of the purified smg p25A GDI estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and sucrose density gradient ultracentrifugation, which are about 54,000 and 65,000, respectively. The isolated cDNA is expressed in Escherichia coli, and the encoded protein exhibits GDI activity. smg p25A GDI is hydrophilic overall, except for one hydrophobic region near the N terminus. smg p25A GDI shares low amino acid sequence homology with the Saccharomyces cerevisiae CDC25-encoded protein, which has been suggested to serve as a factor that regulates the GDP-GTP exchange reaction of the yeast RAS2-encoded protein, but not with the beta gamma subunits of GTP-binding proteins having an alpha beta gamma subunit structure, such as Gs and Gi. The smg p25A GDI mRNA was present in various tissues, including not only tissues in which smg p25A was detectable but also tissues in which it was not detectable. This fact has raised the possibility that smg p25A GDI interacts with another G protein in tissues in which smg p25A is absent.

    Molecular and cellular biology 1990;10;8;4116-22

Gene lists (8)

Gene List Source Species Name Description Gene count
L00000009 G2C Homo sapiens Human PSD Human orthologues of mouse PSD adapted from Collins et al (2006) 1080
L00000011 G2C Homo sapiens Human clathrin Human orthologues of mouse clathrin coated vesicle genes adapted from Collins et al (2006) 150
L00000012 G2C Homo sapiens Human Synaptosome Human orthologues of mouse synaptosome adapted from Collins et al (2006) 152
L00000013 G2C Homo sapiens Human mGluR5 Human orthologues of mouse mGluR5 complex adapted from Collins et al (2006) 52
L00000016 G2C Homo sapiens Human PSP Human orthologues of mouse PSP adapted from Collins et al (2006) 1121
L00000059 G2C Homo sapiens BAYES-COLLINS-HUMAN-PSD-CONSENSUS Human cortex PSD consensus 748
L00000069 G2C Homo sapiens BAYES-COLLINS-HUMAN-PSD-FULL Human cortex biopsy PSD full list 1461
L00000071 G2C Homo sapiens BAYES-COLLINS-MOUSE-PSD-FULL Mouse cortex PSD full list (ortho) 1556
© G2C 2014. The Genes to Cognition Programme received funding from The Wellcome Trust and the EU FP7 Framework Programmes:
EUROSPIN (FP7-HEALTH-241498), SynSys (FP7-HEALTH-242167) and GENCODYS (FP7-HEALTH-241995).

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