G2Cdb::Gene report

Gene id
Gene symbol
Homo sapiens
guanine nucleotide binding protein (G protein), alpha z polypeptide
G00000216 (Mus musculus)

Databases (9)

Curated Gene
OTTHUMG00000030927 (Vega human gene)
ENSG00000128266 (Ensembl human gene)
2781 (Entrez Gene)
360 (G2Cdb plasticity & disease)
GNAZ (GeneCards)
139160 (OMIM)
Marker Symbol
HGNC:4395 (HGNC)
Protein Expression
3011 (human protein atlas)
Protein Sequence
P19086 (UniProt)

Literature (37)

Pubmed - other

  • Reviews in molecular biology and biotechnology: transmembrane signaling by G protein-coupled receptors.

    Luttrell LM

    Division of Endocrinology, Diabetes and Medical Genetics, Department of Medicine, Medical University of South Carolina, 96 Jonathan Lucas Street, 816 CSB, P.O. Box 250624, Charleston, SC 29425, USA. luttrell@musc.edu

    As the most diverse type of cell surface receptor, the importance heptahelical G protein-coupled receptors (GPCRs) to clinical medicine cannot be overestimated. Visual, olfactory and gustatory sensation, intermediary metabolism, cell growth and differentiation are all influenced by GPCR signals. The basic receptor-G protein-effector mechanism of GPCR signaling is tuned by a complex interplay of positive and negative regulatory events that amplify the effect of a hormone binding the receptor or that dampen cellular responsiveness. The association of heptahelical receptors with a variety of intracellular partners other than G proteins has led to the discovery of potential mechanisms of GPCR signaling that extend beyond the classical paradigms. While the physiologic relevance of many of these novel mechanisms of GPCR signaling remains to be established, their existence suggests that the mechanisms of GPCR signaling are even more diverse than previously imagined.

    Molecular biotechnology 2008;39;3;239-64

  • Many sequence variants affecting diversity of adult human height.

    Gudbjartsson DF, Walters GB, Thorleifsson G, Stefansson H, Halldorsson BV, Zusmanovich P, Sulem P, Thorlacius S, Gylfason A, Steinberg S, Helgadottir A, Ingason A, Steinthorsdottir V, Olafsdottir EJ, Olafsdottir GH, Jonsson T, Borch-Johnsen K, Hansen T, Andersen G, Jorgensen T, Pedersen O, Aben KK, Witjes JA, Swinkels DW, den Heijer M, Franke B, Verbeek AL, Becker DM, Yanek LR, Becker LC, Tryggvadottir L, Rafnar T, Gulcher J, Kiemeney LA, Kong A, Thorsteinsdottir U and Stefansson K

    deCODE Genetics, 101 Reykjavik, Iceland. daniel.gudbjartsson@decode.is

    Adult human height is one of the classical complex human traits. We searched for sequence variants that affect height by scanning the genomes of 25,174 Icelanders, 2,876 Dutch, 1,770 European Americans and 1,148 African Americans. We then combined these results with previously published results from the Diabetes Genetics Initiative on 3,024 Scandinavians and tested a selected subset of SNPs in 5,517 Danes. We identified 27 regions of the genome with one or more sequence variants showing significant association with height. The estimated effects per allele of these variants ranged between 0.3 and 0.6 cm and, taken together, they explain around 3.7% of the population variation in height. The genes neighboring the identified loci cluster in biological processes related to skeletal development and mitosis. Association to three previously reported loci are replicated in our analyses, and the strongest association was with SNPs in the ZBTB38 gene.

    Nature genetics 2008;40;5;609-15

  • Toward a confocal subcellular atlas of the human proteome.

    Barbe L, Lundberg E, Oksvold P, Stenius A, Lewin E, Björling E, Asplund A, Pontén F, Brismar H, Uhlén M and Andersson-Svahn H

    Department of Biotechnology, AlbaNova University Center, Royal Institute of Technology, SE-106 91 Stockholm, Sweden.

    Information on protein localization on the subcellular level is important to map and characterize the proteome and to better understand cellular functions of proteins. Here we report on a pilot study of 466 proteins in three human cell lines aimed to allow large scale confocal microscopy analysis using protein-specific antibodies. Approximately 3000 high resolution images were generated, and more than 80% of the analyzed proteins could be classified in one or multiple subcellular compartment(s). The localizations of the proteins showed, in many cases, good agreement with the Gene Ontology localization prediction model. This is the first large scale antibody-based study to localize proteins into subcellular compartments using antibodies and confocal microscopy. The results suggest that this approach might be a valuable tool in conjunction with predictive models for protein localization.

    Molecular & cellular proteomics : MCP 2008;7;3;499-508

  • Mechanism of the receptor-catalyzed activation of heterotrimeric G proteins.

    Oldham WM, Van Eps N, Preininger AM, Hubbell WL and Hamm HE

    Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-6600, USA.

    Heptahelical receptors activate intracellular signaling pathways by catalyzing GTP for GDP exchange on the heterotrimeric G protein alpha subunit (G alpha). Despite the crucial role of this process in cell signaling, little is known about the mechanism of G protein activation. Here we explore the structural basis for receptor-mediated GDP release using electron paramagnetic resonance spectroscopy. Binding to the activated receptor (R*) causes an apparent rigid-body movement of the alpha5 helix of G alpha that would perturb GDP binding at the beta6-alpha5 loop. This movement was not observed when a flexible loop was inserted between the alpha5 helix and the R*-binding C terminus, which uncouples R* binding from nucleotide exchange, suggesting that this movement is necessary for GDP release. These data provide the first direct observation of R*-mediated conformational changes in G proteins and define the structural basis for GDP release from G alpha.

    Nature structural & molecular biology 2006;13;9;772-7

  • 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

  • Galphaz inhibits serum response factor-dependent transcription by inhibiting Rho signaling.

    Dutt P, Jaffe AB, Merdek KD, Hall A and Toksoz D

    Physiology Department, Tufts University School of Medicine, Boston, Massachusetts 02111, USA.

    Galpha12/13 or Galphaq signals induce activation of Rho GTPase, leading to serum response factor (SRF)-mediated gene transcription and actin cytoskeletal organization; however, less is known regarding how Rho pathway signals are down-regulated. Here we report that Galphaz signals inhibit serum response factor (SRF)-dependent transcription. Galphaz expression inhibits Galpha12/13-, Galphaq-, and Rho guanine nucleotide exchange factor (GEF)-induced serum response element (SRE) reporter activation in human embryonic kidney 293T and PC-12 cells. Expression of Galphaz mutants with defective fatty acylation has no inhibitory effect. Expression of Galphaz, but not Galphai, attenuates serum-induced SRE reporter activation, suggesting that Galphaz can down-regulate endogenous signals leading to SRF. Whereas Galphaz also blocks SRE reporter induction by the activated mutant RhoAL63, it does not affect Galpha12- or Rho GEF-induced RhoA activation or RhoAL63-GTP binding in vivo. Moreover, Galphaz does not inhibit SRE reporter induction by an activated form of Rho kinase. Because Galphaz inhibits RhoAL63/A188-induced reporter activation, phosphorylation of RhoA on serine 188 does not seem to be involved; furthermore, RhoA subcellular localization was not affected. Use of pharmacologic inhibitors implies that Galphaz-induced reduction of SRE reporter activation occurs via a mechanism other than adenylate cyclase modulation. These findings suggest that Galphaz signals may attenuate Rho-induced stimulation of SRF-mediated transcription.

    Funded by: NIDDK NIH HHS: T32-DK07542

    Molecular pharmacology 2004;66;6;1508-16

  • 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

  • A genome annotation-driven approach to cloning the human ORFeome.

    Collins JE, Wright CL, Edwards CA, Davis MP, Grinham JA, Cole CG, Goward ME, Aguado B, Mallya M, Mokrab Y, Huckle EJ, Beare DM and Dunham I

    The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SA, UK.

    We have developed a systematic approach to generating cDNA clones containing full-length open reading frames (ORFs), exploiting knowledge of gene structure from genomic sequence. Each ORF was amplified by PCR from a pool of primary cDNAs, cloned and confirmed by sequencing. We obtained clones representing 70% of genes on human chromosome 22, whereas searching available cDNA clone collections found at best 48% from a single collection and 60% for all collections combined.

    Genome biology 2004;5;10;R84

  • Analysis of RGSZ1 protein interaction with Galphai subunits.

    Wang Y and Young KH

    Neuroscience Discovery Research, Wyeth Research, Princeton, New Jersey 08543, USA.

    RGSZ1 has been reported to interact with G-protein subunits of the Galphai family and function as a GTPase-accelerating protein on intrinsic Galphai GTPase activity. This article describes several experimental approaches and assays used to investigate the effect of RGSZ1 on Galphai subunits. The formats described here include physical and functional interaction assays by which the association of RGSZ1 with Galphai is explored both in vitro and in vivo. The methods analyzing physical interaction include pull-down and coimmunoprecipitation assays. We also apply yeast two-hybrid techniques to detect RGSZ1 protein interaction with Galpha subunits. Additionally, we developed several functional assay systems to identify the functional relationship between RGSZ1 and Galphai, such as the single turnover GTPase assay, yeast pheromone response assay, mitogen-activated protein kinase assay, and serum response element reporter assay.

    Methods in enzymology 2004;390;31-52

  • Regulator of G protein signaling Z1 (RGSZ1) interacts with Galpha i subunits and regulates Galpha i-mediated cell signaling.

    Wang Y, Ho G, Zhang JJ, Nieuwenhuijsen B, Edris W, Chanda PK and Young KH

    Neuroscience Discovery Research, Wyeth Research, Princeton, New Jersey 08543-8000, USA. wangy4@wyeth.com

    Regulator of G protein signaling (RGS) proteins constitute a family of over 20 proteins that negatively regulate heterotrimeric G protein-coupled receptor signaling pathways by enhancing endogenous GTPase activities of G protein alpha subunits. RGSZ1, one of the RGS proteins specifically localized to the brain, has been cloned previously and described as a selective GTPase accelerating protein for Galpha(z) subunit. Here, we employed several methods to provide new evidence that RGSZ1 interacts not only with Galpha(z,) but also with Galpha(i), as supported by in vitro binding assays and functional studies. Using glutathione S-transferase fusion protein pull-down assays, glutathione S-transferase-RGSZ1 protein was shown to bind (35)S-labeled Galpha(i1) protein in an AlF(4)(-)dependent manner. The interaction between RGSZ1 and Galpha(i) was confirmed further by co-immunoprecipitation studies and yeast two-hybrid experiments using a quantitative luciferase reporter gene. Extending these observations to functional studies, RGSZ1 accelerated endogenous GTPase activity of Galpha(i1) in single-turnover GTPase assays. Human RGSZ1 functionally regulated GPA1 (a yeast Galpha(i)-like protein)-mediated yeast pheromone response when expressed in a SST2 (yeast RGS protein) knockout strain. In PC12 cells, transfected RGSZ1 blocked mitogen-activated protein kinase activity induced by UK14304, an alpha(2)-adrenergic receptor agonist. Furthermore, RGSZ1 attenuated D2 dopamine receptor agonist-induced serum response element reporter gene activity in Chinese hamster ovary cells. In summary, these data suggest that RGSZ1 serves as a GTPase accelerating protein for Galpha(i) and regulates Galpha(i)-mediated signaling, thus expanding the potential role of RGSZ1 in G protein-mediated cellular activities.

    The Journal of biological chemistry 2002;277;50;48325-32

  • Inactivation of Galpha(z) causes disassembly of the Golgi apparatus.

    Nagahama M, Usui S, Shinohara T, Yamaguchi T, Tani K and Tagaya M

    School of Life Science, Tokyo University of Pharmacy and Life Science, Hachioji, Tokyo 192-0392, Japan.

    We showed previously that overexpression of the alpha subunit of G(z) or G(i2) suppresses nordihydroguaiaretic acid-induced Golgi disassembly. To determine whether the active form of Galpha is required to maintain the structure of the Golgi apparatus, we examined the effects of a series of Galpha GAPs, regulators of G protein signaling (RGS) proteins, on the Golgi structure. Expression of RGSZ1 or RGSZ2, both of which exhibit high selectivity for Galpha(z), markedly induced dispersal of the Golgi apparatus, whereas expression of RGS proteins that are rather selective for Galpha(q) or other Galpha(i) species did not. A mutated RGSZ1, which is deficient in the interaction with Galpha(z), did not induce Golgi disassembly. These results suggest that the active form of Galpha(z), but not Galpha(i2), is crucial for maintenance of the structure of the Golgi apparatus. Consistent with this idea, Golgi disruption also took place in cells transfected with a dominant-negative Galpha(z) mutant. Although previous studies showed that the expression of Galpha(z) is confined to neuronal cells and platelets, immunofluorescence and mRNA expression analyses revealed that it is also expressed, albeit at low levels, in non-neuronal cells, and is located in the Golgi apparatus. These results taken together suggest a general regulatory role for Galpha(z) in the control of the Golgi structure.

    Journal of cell science 2002;115;Pt 23;4483-93

  • Impaired interactions between mouse Eyal harboring mutations found in patients with branchio-oto-renal syndrome and Six, Dach, and G proteins.

    Ozaki H, Watanabe Y, Ikeda K and Kawakami K

    Department of Biology, Jichi Medical School, Kawachi, Tochigi, Japan.

    Mutations in the EYA1 gene are responsible for branchio-oto-renal (BOR) syndrome as well as for other ocular defects. Most of the mutations are located within or in the vicinity of the EYA domain, which is highly conserved in the EYA protein family. The EYA domain is required for protein-protein interactions, which are important to the biological function of EYA proteins. To determine how EYA1 mutations cause BOR syndrome and/or ocular defects, we tested the effects of Eya1 mutations on interactions with Six. Dach, and G proteins by mammalian two-hybrid and GST-pulldown assays. Defective interactions were noted between BOR-type mutations S486P and L504R of Eya1 and Dach1, G proteins, and some Six proteins. These mutations impaired the activation of transcription from a Six-responsive gene, myogenin, with Six5. S486P and L504R showed an altered digestion pattern with trypsin, and L504R also decreased the sensitivity to V8 protease digestion and produced a peptide fragment with a different M(r). Our results suggest that defective protein-protein interactions of the mutations in the EYA domain underlie BOR syndrome and that SIX, DACH, and/or G proteins are possibly involved in the pathogenic processes.

    Journal of human genetics 2002;47;3;107-16

  • The alpha subunits of Gz and Gi interact with the eyes absent transcription cofactor Eya2, preventing its interaction with the six class of homeodomain-containing proteins.

    Fan X, Brass LF, Poncz M, Spitz F, Maire P and Manning DR

    Departments of Pharmacology, Medicine and Pathology, and Pediatrics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA.

    Yeast two-hybrid techniques were used to identify possible effectors for the heterotrimeric G protein G(z) in human bone marrow cells. Eya2, a human homologue of the Drosophila Eya transcription co-activator, was identified. Eya2 interacts with activated Galpha(z) and at least one other member of the Galpha(i) family, Galpha(i2). Interactions were confirmed in mammalian two-hybrid and glutathione S-transferase fusion protein pull-down assays. Regions of Eya2-mediating interaction were mapped to the C-terminal Eya consensus domain. Eya2 is an intrinsically cytosolic protein that is translocated to the nucleus by members of the Six homeodomain-containing family of proteins. Activated Galpha(z) and Galpha(i2) prevent Eya2 translocation and inhibit Six/Eya2-mediated activation of a reporter gene controlled through the MEF3/TATA promoter. Although G proteins are known to regulate the activity of numerous transcription factors, this regulation is normally achieved indirectly via one or more intermediates. We show here a novel functional regulation of a co-activator directly by G protein subunits.

    Funded by: NHLBI NIH HHS: HL45181

    The Journal of biological chemistry 2000;275;41;32129-34

  • Functional interaction between Galpha(z) and Rap1GAP suggests a novel form of cellular cross-talk.

    Meng J, Glick JL, Polakis P and Casey PJ

    Departments of Pharmacology and Cancer Biology and of Biochemistry, Duke University Medical Center, Durham, North Carolina 27710, USA.

    G(z) is a member of the G(i) family of trimeric G proteins whose primary role in cell physiology is still unknown. In an ongoing effort to elucidate the cellular functions of G(z), the yeast two-hybrid system was employed to identify proteins that specifically interact with a mutationally activated form of Galpha(z). One of the molecules uncovered in this screen was Rap1GAP, a previously identified protein that specifically stimulates GTP hydrolytic activity of the monomeric G protein Rap1 and thus is believed to function as a down-regulator of Rap1 signaling. Like G(z), the precise role of Rap1 in cell physiology is poorly understood. Biochemical analysis using purified recombinant proteins revealed that the physical interaction between Galpha(z) and Rap1GAP blocks the ability of RGSs (regulators of G protein signaling) to stimulate GTP hydrolysis of the alpha subunit, and also attenuates the ability of activated Galpha(z) to inhibit adenylyl cyclase. Structure-function analyses indicate that the first 74 amino-terminal residues of Rap1GAP, a region distinct from the catalytic core domain responsible for the GAP activity toward Rap1, is required for this interaction. Co-precipitation assays revealed that Galpha(z), Rap1GAP, and Rap1 can form a stable complex. These data suggest that Rap1GAP acts as a signal integrator to somehow coordinate and/or integrate G(z) signaling and Rap1 signaling in cells.

    Funded by: NIGMS NIH HHS: GM 55717

    The Journal of biological chemistry 1999;274;51;36663-9

  • RGS7 and RGS8 differentially accelerate G protein-mediated modulation of K+ currents.

    Saitoh O, Kubo Y, Odagiri M, Ichikawa M, Yamagata K and Sekine T

    Department of Molecular and Cellular Neurobiology, Tokyo Metropolitan Institute for Neuroscience, 2-6 Musashidai, Fuchu-shi, Tokyo 183-8526, Japan. osaito@tmin.ac.jp

    The recently discovered family of RGS (regulators of G protein signaling) proteins acts as GTPase activating proteins which bind to alpha subunits of heterotrimeric G proteins. We previously showed that a brain-specific RGS, RGS8 speeds up the activation and deactivation kinetics of the G protein-coupled inward rectifier K+ channel (GIRK) upon receptor stimulation (Saitoh, O., Kubo, Y., Miyatani, Y., Asano, T., and Nakata, H. (1997) Nature 390, 525-529). Here we report the isolation of a full-length rat cDNA of another brain-specific RGS, RGS7. In situ hybridization study revealed that RGS7 mRNA is predominantly expressed in Golgi cells within granule cell layer of cerebellar cortex. We observed that RGS7 recombinant protein binds preferentially to Galphao, Galphai3, and Galphaz. When co-expressed with GIRK1/2 in Xenopus oocytes, RGS7 and RGS8 differentially accelerate G protein-mediated modulation of GIRK. RGS7 clearly accelerated activation of GIRK current similarly with RGS8 but the acceleration effect of deactivation was significantly weaker than that of RGS8. These acceleration properties of RGS proteins may play important roles in the rapid regulation of neuronal excitability and the cellular responses to short-lived stimulations.

    The Journal of biological chemistry 1999;274;14;9899-904

  • RGSZ1, a Gz-selective regulator of G protein signaling whose action is sensitive to the phosphorylation state of Gzalpha.

    Glick JL, Meigs TE, Miron A and Casey PJ

    Department of Biochemistry, Duke University Medical Center, Durham, North Carolina 27710-3686, USA.

    Regulators of G protein signaling (RGS) are a family of proteins that attenuate the activity of the trimeric G proteins. RGS proteins act as GTPase-activating proteins (GAPs) for the alpha subunits of several trimeric G proteins, much like the GAPs that regulate the activity of monomeric G proteins such as Ras. RGS proteins have been cloned from many eukaryotes, and those whose biochemical activity has been characterized regulate the members of the Gi family of G proteins; some forms can also act on Gq proteins. In an ongoing effort to elucidate the role of Gzalpha in cell signaling, the yeast two-hybrid system was employed to identify proteins that could interact with a mutationally activated form of Gzalpha. A novel RGS, termed RGSZ1, was identified that is most closely related to two existing RGS proteins termed RetRGS1 and GAIP. Northern blot analysis revealed that expression of RGSZ1 was limited to brain, and expression was particularly high in the caudate nucleus. Biochemical characterization of recombinant RGSZ1 protein revealed that RGSZ1 was indeed a GAP and, most significantly, showed a marked preference for Gzalpha over other members of the Gialpha family. Phosphorylation of Gzalpha by protein kinase C, an event known to occur in cells and that was previously shown to influence alpha-betagamma interactions of Gz, rendered the G protein much less susceptible to RGSZ1 action.

    Funded by: NIGMS NIH HHS: GM19119

    The Journal of biological chemistry 1998;273;40;26008-13

  • The mammalian calcium-binding protein, nucleobindin (CALNUC), is a Golgi resident protein.

    Lin P, Le-Niculescu H, Hofmeister R, McCaffery JM, Jin M, Hennemann H, McQuistan T, De Vries L and Farquhar MG

    Division of Cellular and Molecular Medicine and Department of Pathology, University of California, San Diego, La Jolla, California 92093-0651, USA.

    We have identified CALNUC, an EF-hand, Ca2+-binding protein, as a Golgi resident protein. CALNUC corresponds to a previously identified EF-hand/calcium-binding protein known as nucleobindin. CALNUC interacts with Galphai3 subunits in the yeast two-hybrid system and in GST-CALNUC pull-down assays. Analysis of deletion mutants demonstrated that the EF-hand and intervening acidic regions are the site of CALNUC's interaction with Galphai3. CALNUC is found in both cytosolic and membrane fractions. The membrane pool is tightly associated with the luminal surface of Golgi membranes. CALNUC is widely expressed, as it is detected by immunofluorescence in the Golgi region of all tissues and cell lines examined. By immunoelectron microscopy, CALNUC is localized to cis-Golgi cisternae and the cis-Golgi network (CGN). CALNUC is the major Ca2+-binding protein detected by 45Ca2+-binding assay on Golgi fractions. The properties of CALNUC and its high homology to calreticulin suggest that it may play a key role in calcium homeostasis in the CGN and cis-Golgi cisternae.

    Funded by: NCI NIH HHS: CA 58689; NIDDK NIH HHS: DK 17780, R01 DK017780

    The Journal of cell biology 1998;141;7;1515-27

  • Multiple coupling of human D5 dopamine receptors to guanine nucleotide binding proteins Gs and Gz.

    Sidhu A, Kimura K, Uh M, White BH and Patel S

    Department of Pediatrics, Georgetown University Medical Center, Washington, DC 20007, USA.

    We have demonstrated previously that D1 dopamine receptors are coupled to both Gs alpha and Go alpha. We examine here the coupling between human D5 dopamine receptors and G proteins in transfected rat pituitary GH4C1 cells. Similar to D1 receptors, cholera toxin treatment of cells reduced, but did not abolish, D5 agonist high-affinity binding sites, indicating D5 receptors couple to both Gs alpha and cholera toxin-insensitive G proteins. The interaction between D5 receptors and Gs alpha was confirmed by immunoprecipitation studies and by the ability of D5 receptors to stimulate adenylyl cyclase. Unlike D1 receptors, D5 receptors did not display any pertussis toxin-sensitive G-protein coupling to Go alpha or Gi alpha. D5 receptors were also not coupled to Gq alpha and were unable to mediate phosphatidylinositol metabolism. Instead, D5 sites appeared to be coupled to an AIF(-)4-sensitive, N-ethylmaleimide-resistant G protein. Anti-Gz alpha caused immunoprecipitation of 24.2 +/- 5.2% of G protein-associated D5 receptors, indicating coupling between D5 and Gz alpha. The coupling to Gz alpha was specific for D5 receptors, because similar associations were not detected between D1 receptors and Gz alpha.

    Funded by: NINDS NIH HHS: NS-29685

    Journal of neurochemistry 1998;70;6;2459-67

  • Functional role of amino-terminal serine16 and serine27 of G alphaZ in receptor and effector coupling.

    Ho MK and Wong YH

    Department of Biology, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon.

    The alpha subunit of Gz (alpha(z)) harbors two N-terminal serine residues (at positions 16 and 27) that serve as protein kinase C-mediated phosphorylation sites. The cognate residues in the alpha subunit of Gt1 provide binding surfaces for the beta1 subunit. We used three serine-to-alanine mutants of alpha(z) to investigate the functional importance of the two N-terminal serine residues. Wild-type or mutant alpha(z) was transiently coexpressed with different receptors and adenylyl cyclase isozymes in human embryonic kidney 293 cells, and agonist-dependent regulation of cyclic AMP accumulation was examined in a setting where all endogenous alpha subunits of G1 were inactivated by pertussis toxin. Replacement of one or both serine residues by alanine did not alter the ability of alpha(z) to interact with delta-opioid, dopamine D2, or adenosine A1 receptors. Its capacity to inhibit endogenous and type VI adenylyl cyclases was also unaffected. Functional release of betagamma subunits from the mutant alpha(z) subunits was not impaired because they transduced betagamma-mediated stimulation of type II adenylyl cyclase. Constitutively active mutants of all four alpha(z) subunits were constructed by the introduction of a Q205L mutation. The activated mutants showed differential abilities to inhibit human choriogonadotropin-mediated cyclic AMP accumulation in luteinizing hormone receptor-transfected cells. Loss of both serine residues, but not either one alone, impaired the receptor-independent inhibition of adenylyl cyclase by the GTPase-deficient mutant. Thus, replacement of the amino-terminal serine residues of alpha(z) has no apparent effect on receptor-mediated responses, but these serine residues may be essential for ensuring transition of alpha(z) into the active conformation.

    Journal of neurochemistry 1997;68;6;2514-22

  • GAIP is membrane-anchored by palmitoylation and interacts with the activated (GTP-bound) form of G alpha i subunits.

    De Vries L, Elenko E, Hubler L, Jones TL and Farquhar MG

    Division of Cellular and Molecular Medicine, University of California at San Diego, La Jolla 92093-0651, USA.

    GAIP (G Alpha Interacting Protein) is a member of the recently described RGS (Regulators of G-protein Signaling) family that was isolated by interaction cloning with the heterotrimeric G-protein G alpha i3 and was recently shown to be a GTPase-activating protein (GAP). In AtT-20 cells stably expressing GAIP, we found that GAIP is membrane-anchored and faces the cytoplasm, because it was not released by sodium carbonate treatment but was digested by proteinase K. When Cos cells were transiently transfected with GAIP and metabolically labeled with [35S]methionine, two pools of GAIP--a soluble and a membrane-anchored pool--were found. Since the N terminus of GAIP contains a cysteine string motif and cysteine string proteins are heavily palmitoylated, we investigated the possibility that membrane-anchored GAIP might be palmitoylated. We found that after labeling with [3H]palmitic acid, the membrane-anchored pool but not the soluble pool was palmitoylated. In the yeast two-hybrid system, GAIP was found to interact specifically with members of the G alpha i subfamily, G alpha i1, G alpha i2, G alpha i3, G alpha z, and G alpha o, but not with members of other G alpha subfamilies, G alpha s, G alpha q, and G alpha 12/13. The C terminus of G alpha i3 is important for binding because a 10-aa C-terminal truncation and a point mutant of G alpha i3 showed significantly diminished interaction. GAIP interacted preferentially with the activated (GTP) form of G alpha i3, which is in keeping with its GAP activity. We conclude that GAIP is a membrane-anchored GAP with a cysteine string motif. This motif, present in cysteine string proteins found on synaptic vesicles, pancreatic zymogen granules, and chromaffin granules, suggests GAIP's possible involvement in membrane trafficking.

    Funded by: NCI NIH HHS: CA58689, F32 CA066289; NIDDK NIH HHS: DK17780, R01 DK017780; NIGMS NIH HHS: GM07752, T32 GM007752

    Proceedings of the National Academy of Sciences of the United States of America 1996;93;26;15203-8

  • RGS10 is a selective activator of G alpha i GTPase activity.

    Hunt TW, Fields TA, Casey PJ and Peralta EG

    Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138, USA.

    Polypeptides that define a protein family termed RGS (for regulators of G-protein signalling) are encoded by the SST2 gene of the yeast Saccharomyces cerevisiae, the EGL-10 gene of the nematode Caenorhabdatis elegans, and several related mammalian genes. Genetic studies in invertebrates and mammalian cell-transfection experiments indicate that RGS proteins negatively regulate signalling pathways involving seven transmembrane receptors and heterotrimeric G proteins. However, the biochemical mechanism by which RGS proteins control these pathways is unknown. Here we report the characterization of human RGS10, a member of this protein family. Co-immunoprecipitation studies demonstrate that RGS10 associates specifically with the activated forms of two related G-protein subunits, G alphai3, and G alphaz, but fails to interact with the structurally and functionally distinct G alphas subunit. In vitro assays with purified proteins indicate that RGS10 increases potently and selectively the GTP hydrolytic activity of several members of the G alphai family, including G alphai3, G alphaz, and G alpha0. These results demonstrate that RGS proteins can attenuate signalling pathways involving heterotrimeric G proteins by serving as GTPase-activating proteins for specific types of G alpha subunits.

    Nature 1996;383;6596;175-7

  • The structure of the G protein heterotrimer Gi alpha 1 beta 1 gamma 2.

    Wall MA, Coleman DE, Lee E, Iñiguez-Lluhi JA, Posner BA, Gilman AG and Sprang SR

    Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas 75235, USA.

    The crystallographic structure of the G protein heterotrimer Gi alpha 1(GDP)beta 1 gamma 2 (at 2.3 A) reveals two nonoverlapping regions of contact between alpha and beta, an extended interface between beta and nearly all of gamma, and limited interaction of alpha with gamma. The major alpha/beta interface covers switch II of alpha, and GTP-induced rearrangement of switch II causes subunit dissociation during signaling. Alterations in GDP binding in the heterotrimer (compared with alpha-GDP) explain stabilization of the inactive conformation of alpha by beta gamma. Repeated WD motifs in beta form a circularized sevenfold beta propeller. The conserved cores of these motifs are a scaffold for display of their more variable linkers on the exterior face of each propeller blade.

    Funded by: NIDDK NIH HHS: DK46371; NIGMS NIH HHS: GM34497

    Cell 1995;83;6;1047-58

  • GNAZ in human fetal cochlea: expression, localization, and potential role in inner ear function.

    Magovcevic I, Khetarpal U, Bieber FR and Morton CC

    Department of Genetics, Harvard Medical School, Boston, MA, USA.

    Dissociation of an activated alpha-subunit from the beta-gamma complex directly regulates secondary messenger proteins. To address the potential role of G proteins expressed in human fetal cochlea, degenerate oligonucleotide primers corresponding to the 3'-end of the conserved region of alpha-subunits were used for polymerase chain reaction amplification of reverse-transcribed total human fetal cochlear mRNAs; GNAZ and GNAQ were isolated. These two G proteins are unique among the G-protein family because they lack a typical pertussis modification site. GNAZ is expressed in high levels in neural tissue while GNAQ is ubiquitously expressed. We characterized GNAZ expression using Northern blots, tissue in-situ hybridization and immunohistochemistry techniques to elucidate the potential role of this protein in inner ear function. Our data suggest that GNAZ may play a role in maintaining the ionic balance of perilymphatic and endolymphatic cochlear fluids.

    Funded by: NHLBI NIH HHS: HLO7627; NIDCD NIH HHS: DC00871

    Hearing research 1995;90;1-2;55-64

  • Phosphorylation of Gz alpha by protein kinase C blocks interaction with the beta gamma complex.

    Fields TA and Casey PJ

    Department of Molecular Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710-3686, USA.

    Gz alpha is a G protein alpha subunit with biochemical properties that distinguish it from other members of the G protein alpha subunit family. One such property is its ability to be stoichiometrically phosphorylated by protein kinase C (PKC), both in vitro and in intact cells. The site of this phosphorylation has been mapped to a region near the N terminus of Gz alpha, but no functional significance of the modification has been established. To investigate this question, we have developed a baculovirus/Sf9 cell expression system to produce Gz alpha. The protein purified from Sf9 cells is functional as assessed by its ability both to bind guanine nucleotide in a Mg(2+)-sensitive fashion and to serve as a substrate for phosphorylation by PKC. Furthermore, addition of the G protein beta gamma complex purified from bovine brain inhibits phosphorylation of Gz alpha in a dose-dependent manner. Conversely, phosphorylation of Gz alpha inhibits its ability to interact with beta gamma subunits. These results establish a functional consequence for PKC-catalyzed phosphorylation of Gz alpha and suggest a mechanism for regulation of signaling through Gz by preventing reassociation of its subunits.

    The Journal of biological chemistry 1995;270;39;23119-25

  • Structural determinants for activation of the alpha-subunit of a heterotrimeric G protein.

    Lambright DG, Noel JP, Hamm HE and Sigler PB

    Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06510.

    The 1.8 A crystal structure of transducin alpha.GDP, when compared to that of the activated complex with GTP-gamma S, reveals the nature of the conformational changes that occur on activation of a heterotrimeric G-protein alpha-subunit. Structural changes initiated by direct contacts with the terminal phosphate of GTP propagate to regions that have been implicated in effector activation. The changes are distinct from those observed in other members of the GTPase superfamily.

    Nature 1994;369;6482;621-8

  • Lipid modifications of G proteins: alpha subunits are palmitoylated.

    Linder ME, Middleton P, Hepler JR, Taussig R, Gilman AG and Mumby SM

    Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas 75235.

    A small number of membrane-associated proteins are reversibly and covalently modified with palmitic acid. Palmitoylation of G-protein alpha and beta subunits was assessed by metabolic labeling of subunits expressed in simian COS cells or insect Sf9 cells. The fatty acid was incorporated into all of the alpha subunits examined (alpha s, alpha o, alpha i1, alpha i2, alpha i3, alpha z, and alpha q), including those that are also myristoylated (alpha o, alpha i, and alpha z). Palmitate was released by treatment with base, suggesting attachment to the protein through a thioester or ester bond. Limited tryptic digestion of activated alpha o and alpha s resulted in release of the amino-terminal portions of the proteins and radioactive palmitate. These data are consistent with palmitoylation of the proteins near their amino termini, most likely on Cys-3. Reversible acylation of G-protein alpha subunits may provide an additional mechanism for regulation of signal transduction.

    Funded by: NIGMS NIH HHS: GM34497

    Proceedings of the National Academy of Sciences of the United States of America 1993;90;8;3675-9

  • Analysis of Gz alpha by site-directed mutagenesis. Sites and specificity of protein kinase C-dependent phosphorylation.

    Lounsbury KM, Schlegel B, Poncz M, Brass LF and Manning DR

    Department of Pharmacology, University of Pennsylvania School of Medicine, Philadelphia.

    The G protein alpha subunit Gz alpha is a substrate for phosphorylation by protein kinase C. The phosphorylation has been documented both in human platelets and in vitro and is characterized by a high degree of selectivity in relation to other G protein alpha subunits. We have demonstrated previously by phosphoamino acid analysis and CNBr peptide mapping that phosphorylation occurs at a serine residue(s) within the NH2-terminal 53 residues of Gz alpha. In this study, we have examined the site of phosphorylation using site-directed mutagenesis. Gz alpha variants containing selected substitutions of alanine for serine residues were expressed in human kidney 293 cells, and the ability of each to be phosphorylated in response to phorbol 12-myristate 13-acetate was examined. A focus was placed on Ser25 and Ser27, the 2 serine residues within a sequence of Gz alpha used to obtain a phosphorylation-sensitive antibody. The results demonstrate that Ser27 is the primary site of phosphorylation. Conversion of Ser27 to an alanine resulted in a 65% decrease in incorporation of [32P] phosphate; conversion of Ser25 had no effect. Conversion of Ser16, which like Ser25 and Ser27 conforms to a consensus site for protein kinase C, resulted in a modest (15%) decrease. The conversion of both Ser16 and Ser27 resulted in an 80% suppression of incorporation. In addition to these results, we have extended studies of the subunit and kinase selectivity of phosphorylation in platelets. We show here that under conditions promoting phorbol 12-myristate 13-acetate-stimulated phosphorylation of Gz alpha in permeabilized platelets, Gq alpha is not phosphorylated. Moreover, Gi alpha, Gz alpha, and Gq alpha were not phosphorylated in response to analogues of cAMP or cGMP. Thus, only Gz alpha is phosphorylated in platelets and only in response to activation of protein kinase C.

    Funded by: NCI NIH HHS: CA39712; NHLBI NIH HHS: HL45181

    The Journal of biological chemistry 1993;268;5;3494-8

  • Evolution of the mammalian G protein alpha subunit multigene family.

    Wilkie TM, Gilbert DJ, Olsen AS, Chen XN, Amatruda TT, Korenberg JR, Trask BJ, de Jong P, Reed RR, Simon MI et al.

    Biology Division, California Institute of Technology, Pasadena 91125.

    Heterotrimeric guanine nucleotide binding proteins (G proteins) transduce extracellular signals received by transmembrane receptors to effector proteins. The multigene family of G protein alpha subunits, which interact with receptors and effectors, exhibit a high level of sequence diversity. In mammals, 15 G alpha subunit genes can be grouped by sequence and functional similarities into four classes. We have determined the murine chromosomal locations of all 15 G alpha subunit genes using an interspecific backcross derived from crosses of C57BL/6J and Mus spretus mice. These data, in combination with mapping studies in humans, have provided insight into the events responsible for generating the genetic diversity found in the mammalian alpha subunit genes and a framework for elucidating the role of the G alpha subunits in disease.

    Nature genetics 1992;1;2;85-91

  • Identification of Gz alpha as a pertussis toxin-insensitive G protein in human platelets and megakaryocytes.

    Gagnon AW, Manning DR, Catani L, Gewirtz A, Poncz M and Brass LF

    Department of Medicine, University of Pennsylvania, Philadelphia 19104.

    G proteins mediate the interaction between cell surface receptors and intracellular effectors. Recent studies have shown that human retina and rat brain contain mRNA encoding a novel 40-Kd G protein alpha subunit referred to as Gz alpha. Studies with an antiserum selective for the predicted sequence of this protein have suggested that a similar protein is present in human platelets and is phosphorylated during platelet activation. To better understand the structure and function of this protein, the present studies examine its sequence in platelets and compare its abundance in human platelets, megakaryocytes, and two megakaryoblastic cell lines, HEL cells and Dami cells. Three different Gz alpha-selective antisera reacted with a 40-Kd protein in platelet membranes. None of these detected a corresponding protein in HEL or Dami cells, despite the presence in both cell lines of proteins recognized by antisera selective for three members of the Gi alpha family. Northern blotting with a Gz alpha-specific probe prepared from retinal Gz alpha showed two hybridizing species in platelet RNA: a major band at 3.5 kb and a minor band at 2.2 kb. Both were detectable in HEL and Dami cells, but at greatly reduced levels compared with platelets. RNA encoding Gz alpha was also detected in individual human megakaryocytes by in situ hybridization. The amount present approached that of Gi alpha 2' the most abundant of the Gi alpha species present in platelets. The complete sequence of the platelet homolog to Gz alpha was determined from platelet RNA amplified by the polymerase chain reaction. The encoded protein was the same as those obtained in brain and retina. Thus, based on immunoreactivity and nucleotide sequencing, platelets and megakaryocytes contain substantial quantities of a protein identical to brain and retinal Gz alpha. The paucity of Gz alpha protein and RNA in the megakaryoblastic cell lines suggests that either there has been a selective loss of the ability to synthesize Gz alpha from these cells or that Gz alpha appears at a later stage in megakaryocyte development than does Gi alpha.

    Funded by: NCI NIH HHS: CA39712; NHLBI NIH HHS: HL40387, HL45181; ...

    Blood 1991;78;5;1247-53

  • Guanine nucleotide-binding regulatory proteins in retinal pigment epithelial cells.

    Jiang M, Pandey S, Tran VT and Fong HK

    Department of Microbiology, University of Southern California School of Medicine, Los Angeles 90033.

    The expression of GTP-binding regulatory proteins (G proteins) in retinal pigment epithelial (RPE) cells was analyzed by RNA blot hybridization and cDNA amplification. Both adult and fetal human RPE cells contain mRNA for multiple G protein alpha subunits (G alpha) including Gs alpha, Gi-1 alpha, Gi-2 alpha, Gi-3 alpha, and Gz alpha (or Gx alpha), where Gs and Gi are proteins that stimulate or inhibit adenylyl cyclase, respectively, and Gz is a protein that may mediate pertussis toxin-insensitive events. Other G alpha-related mRNA transcripts were detected in fetal RPE cells by low-stringency hybridization to Gi-2 alpha and Gs alpha protein-coding cDNA probes. The diversity of G proteins in RPE cells was further studied by cDNA amplification with reverse transcriptase and the polymerase chain reaction. This approach revealed that, besides the above mentioned members of the G alpha gene family, at least two other G alpha subunits are expressed in RPE cells. Human retinal cDNA clones that encode one of the additional G alpha subunits were isolated and characterized. The results indicate that this G alpha subunit belongs to a separate subfamily of G proteins that may be insensitive to inhibition by pertussis toxin.

    Funded by: NEI NIH HHS: EY08364

    Proceedings of the National Academy of Sciences of the United States of America 1991;88;9;3907-11

  • Characterization of the human gene for Gx alpha, a pertussis toxin-insensitive regulatory GTP-binding protein.

    Matsuoka M, Itoh H and Kaziro Y

    Institute of Medical Science, University of Tokyo, Japan.

    We have cloned the human chromosomal gene coding for the alpha subunit of Gx (Gx alpha), a heterotrimeric signal-transducing GTP-binding protein (G protein) that is insensitive to pertussis toxin. Gx alpha cDNA has been cloned both from rat brain (Matsuoka, M., Itoh, H., Kozasa, T., and Kaziro, Y. (1988) Proc. Natl. Acad. Sci. U.S.A. 85, 5384-5388) and from human retina (referred to as Gz alpha, Fong, H.K.W., Yoshimoto, K.K., Eversole-Cire, P., and Simon, M.I. (1988) Proc. Natl. Acad. Sci. U.S.A. 85, 3066-3070). In this paper, we have analyzed the structure of human gene for Gx alpha, which spans more than 60 kilobases. Comparison of the nucleotide sequence of the human chromosomal gene with that of the human retinal Gx alpha cDNA revealed that the gene is composed of three exons and two introns. The first exon contains about 170 base pairs of the 5'-noncoding sequence. The second exon contains the 5'-noncoding and the N-terminal coding sequences, and the third exon contains the C-terminal and the 3'-noncoding sequences. S1 mapping and primer extension analysis have identified the presence of multiple transcription initiation sites, upstream of which were found 12 SP1 binding sites and one CAAT sequence but no TATA sequence. Southern blot analysis indicated that a single copy of the Gx alpha gene is present per haploid human genome. RNA blot hybridization analysis revealed that Gx alpha mRNA is expressed mainly in brain.

    The Journal of biological chemistry 1990;265;22;13215-20

  • Novel localization of a G protein, Gz-alpha, in neurons of brain and retina.

    Hinton DR, Blanks JC, Fong HK, Casey PJ, Hildebrandt E and Simons MI

    Department of Pathology, University of Southern California School of Medicine, Los Angeles 90033.

    Recently, a cDNA coding for a novel G protein alpha-subunit, Gz-alpha, was isolated from a human retinal cDNA library and shown by Northern blot analysis to be expressed at high levels in neural tissues. We have prepared affinity-purified antibodies specifically directed against synthetic Gz-alpha peptides and employed immunohistochemical methods to map the localization of Gz-alpha in human, bovine, and murine retina and brain. By light microscopy, Gz-alpha was localized to the cytoplasm of neurons, with predominant reactivity in ganglion cells of the retina, Purkinje cells of the cerebellum, and most neurons of the hippocampus and cerebral cortex. Reactivity was confined to perikaryon, dendrites, and a very short segment of proximal axons, except for the retinal ganglion cells, in which the axons in the nerve fiber layer showed intense Gz-alpha immunoreactivity proximal to the lamina cribrosa. Pre-embedding immunoelectron microscopy demonstrated the presence of focal Gz-alpha immunoreactivity on the nuclear membranes, endoplasmic reticulum, and plasma membranes of Purkinje cell perikarya and in association with microtubules in their proximal dendrites. Subcellular fractionation studies confirmed the association of Gz-alpha with plasma and intracellular membranes. The localization of Gz-alpha and its unique amino acid sequence suggest that it may have a specialized function in neural tissues.

    Funded by: NEI NIH HHS: EY03040, EY03042; NIA NIH HHS: AG0-7891-01; ...

    The Journal of neuroscience : the official journal of the Society for Neuroscience 1990;10;8;2763-70

  • G-protein alpha-subunit expression, myristoylation, and membrane association in COS cells.

    Mumby SM, Heukeroth RO, Gordon JI and Gilman AG

    Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas 75235.

    Myristoylation of seven different alpha subunits of guanine nucleotide-binding regulatory proteins (G proteins) was examined by expressing these proteins in monkey kidney COS cells. Metabolic labeling studies of cells transfected with cytomegalovirus-based expression vectors indicated that [3H]myristate was incorporated into alpha i1, alpha i2, alpha i3, alpha 0, alpha t, and alpha z but not alpha s subunits. The role of myristoylation in the association of alpha subunits with membranes was analyzed by site-directed mutagenesis and by substitution of myristate with a less hydrophobic analog, 10-(propoxy)decanoate (11-oxamyristate). Myristoylation of alpha 0 was blocked when an alanine residue was substituted for its amino-terminal glycine, as was association of the protein with membranes. Substitution of the myristoyl group with 11-oxamyristate affected the cellular distribution of a subset of acylated alpha subunits. The results are consistent with a model wherein the hydrophobic interaction of myristate with the bilayer permits continued association of the protein with the plasma membrane when G-protein alpha subunits dissociate from beta gamma.

    Funded by: NIAID NIH HHS: AI27179; NIGMS NIH HHS: GM08200, GM34497

    Proceedings of the National Academy of Sciences of the United States of America 1990;87;2;728-32

  • Chromosomal localization of genes encoding guanine nucleotide-binding protein subunits in mouse and human.

    Blatt C, Eversole-Cire P, Cohn VH, Zollman S, Fournier RE, Mohandas LT, Nesbitt M, Lugo T, Jones DT, Reed RR et al.

    Weizmann Institute, Rehovoth, Israel.

    A variety of genes have been identified that specify the synthesis of the components of guanine nucleotide-binding proteins (G proteins). Eight different guanine nucleotide-binding alpha-subunit proteins, two different beta subunits, and one gamma subunit have been described. Hybridization of cDNA clones with DNA from human-mouse somatic cell hybrids was used to assign many of these genes to human chromosomes. The retinal-specific transducin subunit genes GNAT1 and GNAT2 were on chromosomes 3 and 1; GNAI1, GNAI2, and GNAI3 were assigned to chromosomes 7, 3, and 1, respectively; GNAZ and GNAS were found on chromosomes 22 and 20. The beta subunits were also assigned--GNB1 to chromosome 1 and GNB2 to chromosome 7. Restriction fragment length polymorphisms were used to map the homologues of some of these genes in the mouse. GNAT1 and GNAI2 were found to map adjacent to each other on mouse chromosome 9 and GNAT2 was mapped on chromosome 17. The mouse GNB1 gene was assigned to chromosome 19. These mapping assignments will be useful in defining the extent of the G alpha gene family and may help in attempts to correlate specific genetic diseases with genes corresponding to G proteins.

    Proceedings of the National Academy of Sciences of the United States of America 1988;85;20;7642-6

  • Sequence analysis of cDNA and genomic DNA for a putative pertussis toxin-insensitive guanine nucleotide-binding regulatory protein alpha subunit.

    Matsuoka M, Itoh H, Kozasa T and Kaziro Y

    Institute of Medical Science, University of Tokyo, Japan.

    We have isolated cDNA clones from rat C6 glioma cells coding for several guanine nucleotide-binding regulatory protein (G protein) alpha subunits (G alpha). The cDNA clones were then used to isolate human chromosomal genes. Among human genomic clones isolated by cross-hybridization with the rat cDNA for the alpha subunit of the inhibitory G protein Gi2, termed Gi2 alpha, a clone designated lambda HGi62 was found to contain a sequence that is highly homologous but distinct from any of the known G alpha sequences, and we have tentatively designated this sequence Gx alpha. We have searched a rat brain cDNA library with the Gx alpha sequence and isolated a cDNA clone containing a rat sequence similar to human Gx alpha. The cDNA contained a single open reading frame of 1065 nucleotides coding for a protein of 355 amino acids with a calculated molecular weight of 40,879. The amino acid sequence of rat Gx alpha shows 66% and 40% similarity with rat Gi2 alpha and rat Gs alpha (the alpha subunit of the stimulatory G protein), respectively. By RNA blot hybridization analysis, mRNA of approximately 3.2 kilobases was detected mainly in brain. Interestingly, the deduced amino acid sequence of Gx alpha predicts that the Gx alpha protein may be refractory to modification by pertussis toxin since the cysteine residue in the fourth position from the C terminus of pertussis toxin-sensitive G alpha is replaced by isoleucine.

    Proceedings of the National Academy of Sciences of the United States of America 1988;85;15;5384-8

  • Identification of a GTP-binding protein alpha subunit that lacks an apparent ADP-ribosylation site for pertussis toxin.

    Fong HK, Yoshimoto KK, Eversole-Cire P and Simon MI

    Division of Biology, California Institute of Technology, Pasadena 91125.

    Recent molecular cloning of cDNA for the alpha subunit of bovine transducin (a guanine nucleotide-binding regulatory protein, or G protein) has revealed the presence of two retinal-specific transducins, called Tr and Tc, which are expressed in rod or cone photoreceptor cells. In a further study of G-protein diversity and signal transduction in the retina, we have identified a G-protein alpha subunit, which we refer to as Gz alpha, by isolating a human retinal cDNA clone that cross-hybridizes at reduced stringency with bovine Tr alpha-subunit cDNA. The deduced amino acid sequence of Gz alpha is 41-67% identical with those of other known G-protein alpha subunits. However, the 355-residue Gz alpha lacks a consensus site for ADP-ribosylation by pertussis toxin, and its amino acid sequence varies within a number of regions that are strongly conserved among all of the other G-protein alpha subunits. We suggest that Gz alpha, which appears to be highly expressed in neural tissues, represents a member of a subfamily of G proteins that mediate signal transduction in pertussis toxin-insensitive systems.

    Funded by: NIGMS NIH HHS: GM34236

    Proceedings of the National Academy of Sciences of the United States of America 1988;85;9;3066-70

Gene lists (6)

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
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
L00000061 G2C Homo sapiens BAYES-COLLINS-MOUSE-PSD-CONSENSUS Mouse cortex PSD consensus (ortho) 984
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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