G2Cdb::Gene report

Gene id
Gene symbol
Homo sapiens
protein phosphatase 1, regulatory (inhibitor) subunit 9B
G00000191 (Mus musculus)

Databases (7)

ENSG00000108819 (Ensembl human gene)
84687 (Entrez Gene)
326 (G2Cdb plasticity & disease)
PPP1R9B (GeneCards)
603325 (OMIM)
Marker Symbol
HGNC:9298 (HGNC)
Protein Sequence
Q96SB3 (UniProt)

Synonyms (2)

  • Spn

Literature (22)

Pubmed - other

  • Defining the human deubiquitinating enzyme interaction landscape.

    Sowa ME, Bennett EJ, Gygi SP and Harper JW

    Department of Pathology, Harvard Medical School, Boston, MA 02115, USA.

    Deubiquitinating enzymes (Dubs) function to remove covalently attached ubiquitin from proteins, thereby controlling substrate activity and/or abundance. For most Dubs, their functions, targets, and regulation are poorly understood. To systematically investigate Dub function, we initiated a global proteomic analysis of Dubs and their associated protein complexes. This was accomplished through the development of a software platform called CompPASS, which uses unbiased metrics to assign confidence measurements to interactions from parallel nonreciprocal proteomic data sets. We identified 774 candidate interacting proteins associated with 75 Dubs. Using Gene Ontology, interactome topology classification, subcellular localization, and functional studies, we link Dubs to diverse processes, including protein turnover, transcription, RNA processing, DNA damage, and endoplasmic reticulum-associated degradation. This work provides the first glimpse into the Dub interaction landscape, places previously unstudied Dubs within putative biological pathways, and identifies previously unknown interactions and protein complexes involved in this increasingly important arm of the ubiquitin-proteasome pathway.

    Funded by: NIA NIH HHS: AG085011, R01 AG011085, R01 AG011085-16; NIGMS NIH HHS: GM054137, GM67945, R01 GM054137, R01 GM054137-14, R01 GM067945

    Cell 2009;138;2;389-403

  • Prefrontal cortex shotgun proteome analysis reveals altered calcium homeostasis and immune system imbalance in schizophrenia.

    Martins-de-Souza D, Gattaz WF, Schmitt A, Rewerts C, Maccarrone G, Dias-Neto E and Turck CW

    Laboratório de Neurociências, Instituto de Psiquiatria, Universidade de São Paulo, Rua. Dr. Ovidio Pires de Campos, no 785, Consolação, São Paulo, SP 05403-010, Brazil.

    Schizophrenia is a complex disease, likely to be caused by a combination of serial alterations in a number of genes and environmental factors. The dorsolateral prefrontal cortex (Brodmann's Area 46) is involved in schizophrenia and executes high-level functions such as working memory, differentiation of conflicting thoughts, determination of right and wrong concepts and attitudes, correct social behavior and personality expression. Global proteomic analysis of post-mortem dorsolateral prefrontal cortex samples from schizophrenia patients and non-schizophrenic individuals was performed using stable isotope labeling and shotgun proteomics. The analysis resulted in the identification of 1,261 proteins, 84 of which showed statistically significant differential expression, reinforcing previous data supporting the involvement of the immune system, calcium homeostasis, cytoskeleton assembly, and energy metabolism in schizophrenia. In addition a number of new potential markers were found that may contribute to the understanding of the pathogenesis of this complex disease.

    European archives of psychiatry and clinical neuroscience 2009;259;3;151-63

  • Asef2 and Neurabin2 cooperatively regulate actin cytoskeletal organization and are involved in HGF-induced cell migration.

    Sagara M, Kawasaki Y, Iemura SI, Natsume T, Takai Y and Akiyama T

    Laboratory of Molecular and Genetic Information, Institute for Molecular and Cellular Biosciences, University of Tokyo, Tokyo, Japan.

    The tumor suppressor adenomatous polyposis coli (APC) is mutated in sporadic and familial colorectal tumors. APC interacts with the Rac1- and Cdc42-specific guanine-nucleotide exchange factors (GEF), Asef and Asef2, which contain an APC-binding region (ABR) in addition to Dbl homology, Pleckstrin homology (PH) and Src homology 3 (SH3) domains. APC stimulates the GEF activity of Asef and Asef2, and thereby regulates cell adhesion and migration. Here we show that Asef2, but not Asef, interacts with Neurabin2/Spinophilin, a scaffold protein that binds to Filamentous actin (F-actin). In response to hepatocyte growth factor (HGF) treatment of HeLa cells, Asef2, Neurabin2 and APC were induced to accumulate and colocalize in lamellipodia and membrane ruffles. Neurabin2 did not affect the GEF activity of Asef2. RNA interference experiments showed that Asef2, Neurabin2 and APC are involved in HGF-induced cell migration. Furthermore, knockdown of Neurabin2 resulted in the suppression of Asef2-induced filopodia formation. These results suggest that Asef2, Neurabin2 and APC cooperatively regulate actin cytoskeletal organization and are required for HGF-induced cell migration.

    Oncogene 2009;28;10;1357-65

  • PPP1R9B (Neurabin 2): involvement and dynamics in the NK immunological synapse.

    Meng X, Kanwar N, Du Q, Goping IS, Bleackley RC and Wilkins JA

    Manitoba Centre for Proteomics and Systems Biology, University of Manitoba, John Buhler Research Centre, Winnipeg, MB, Canada.

    The NK immunological synapse (NKIS) is a dynamic structure dependent on the assembly of membrane, cytoskeletal and signaling components. These serve to focus and generate stimuli for adhesion and orientation of the cytoskeleton for targeted cytolytic granule release. Previous studies have demonstrated the importance of the cytoskeleton in these processes. We previously identified PPP1R9B (neurabin 2, spinophilin) as a cytoskeletal component of the NK-like cell line YTS. We demonstrate that (i) PPP1R9B gradually accumulates at the NKIS in a maturation stage-dependent manner; (ii) it mimics the early kinetics of actin recruitment to the NKIS but it precedes actin departure from the site; (iii) it is recruited by CD18 stimulation but not by CD28 ligation; (iv) it is required for the maintenance of the cortical F-actin organization in the YTS cells and knocking down PPP1R9B reduces the frequency of YTS-target cell conjugation, possibly due to the collapsed F-actin cytoskeleton in these cells. These results indicate that PPP1R9B is required for synapse formation in the NK cells and suggest that it may be involved in the maintenance of cellular architecture by regulation of actin assembly, possibly acting to stabilize the NKIS until granule release is eminent.

    European journal of immunology 2009;39;2;552-60

  • Spinophilin facilitates dephosphorylation of doublecortin by PP1 to mediate microtubule bundling at the axonal wrist.

    Bielas SL, Serneo FF, Chechlacz M, Deerinck TJ, Perkins GA, Allen PB, Ellisman MH and Gleeson JG

    Neurobiology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA.

    The axonal shafts of neurons contain bundled microtubules, whereas extending growth cones contain unbundled microtubule filaments, suggesting that localized activation of microtubule-associated proteins (MAP) at the transition zone may bundle these filaments during axonal growth. Dephosphorylation is thought to lead to MAP activation, but specific molecular pathways have remained elusive. We find that Spinophilin, a Protein-phosphatase 1 (PP1) targeting protein, is responsible for the dephosphorylation of the MAP Doublecortin (Dcx) Ser 297 selectively at the "wrist" of growing axons, leading to activation. Loss of activity at the "wrist" is evident as an impaired microtubule cytoskeleton along the shaft. These findings suggest that spatially restricted adaptor-specific MAP reactivation through dephosphorylation is important in organization of the neuronal cytoskeleton.

    Funded by: NCRR NIH HHS: P41 RR004050, P41 RR04050; NINDS NIH HHS: K02 NS042749, K02 NS042749-05, P30 NS047101, P30 NS047101-03S1, P30 NS047101-04, R01 NS014718, R01 NS041537, R01 NS041537-05, R01 NS14718

    Cell 2007;129;3;579-91

  • Phosphorylation of spinophilin by ERK and cyclin-dependent PK 5 (Cdk5).

    Futter M, Uematsu K, Bullock SA, Kim Y, Hemmings HC, Nishi A, Greengard P and Nairn AC

    Laboratory of Molecular and Cellular Neuroscience, The Rockefeller University, New York, NY 10021, USA.

    Spinophilin is a protein that binds to protein phosphatase-1 and actin and modulates excitatory synaptic transmission and dendritic spine morphology. We have identified three sites phosphorylated by ERK2 (Ser-15 and Ser-205) and cyclin-dependent PK 5 (Cdk5) (Ser-17), within the actin-binding domain of spinophilin. Cdk5 and ERK2 both phosphorylated spinophilin in intact cells. However, in vitro, phosphorylation by ERK2, but not by Cdk5, was able to modulate the ability of spinophilin to bind to and bundle actin filaments. In neurons and HEK293 cells expressing GFP-tagged variants of spinophilin, imaging studies demonstrated that introduction of a phospho-site mimic (Ser-15 to glutamate) was associated with increased filopodial density. These results support a role for spinophilin phosphorylation by ERK2 in the regulation of spine morphogenesis.

    Funded by: NIDA NIH HHS: DA1044, P01 DA010044; NIMH NIH HHS: MH40899, P01 MH040899

    Proceedings of the National Academy of Sciences of the United States of America 2005;102;9;3489-94

  • Reduced spinophilin but not microtubule-associated protein 2 expression in the hippocampal formation in schizophrenia and mood disorders: molecular evidence for a pathology of dendritic spines.

    Law AJ, Weickert CS, Hyde TM, Kleinman JE and Harrison PJ

    University Department of Psychiatry, Neurosciences Building, Warneford Hospital, Oxford OX3 7JX, UK. amanda.law@psych.ox.ac.uk.

    Objective: Aberrant synaptic connectivity may underlie the involvement of the hippocampus in schizophrenia. There is reasonable neuropathological evidence for a presynaptic pathology but few studies of the postsynaptic component. This study tested the hypothesis that hippocampal dendritic pathology is also present in schizophrenia.

    Method: Using in situ hybridization in sections of hippocampal formation from 10 patients with schizophrenia, 10 patients with mood disorders (three with bipolar disorder and seven with major depression), and 10 healthy comparison subjects, the authors examined the expression of two important dendritic genes: spinophilin, which serves as a marker of dendritic spines, and microtubule-associated protein 2 (MAP2), an overall dendritic marker.

    Results: The patients with schizophrenia had lower levels of spinophilin mRNA in CA4 (hilus), CA3, the subiculum, and the entorhinal cortex than did the normal comparison subjects. The mood disorder group showed similar differences from the comparison group. MAP2 and cyclophilin mRNA did not differ between the groups in any subfield.

    Conclusions: Decreased spinophilin but unchanged MAP2 expression provides molecular evidence for a hippocampal dendritic pathology in schizophrenia that preferentially affects the spines. As spines are the target of most glutamatergic synapses, the data extend the evidence that excitatory synapses are particularly affected. Similar dendritic spine pathology may also occur in mood disorders.

    The American journal of psychiatry 2004;161;10;1848-55

  • Functional proteomics mapping of a human signaling pathway.

    Colland F, Jacq X, Trouplin V, Mougin C, Groizeleau C, Hamburger A, Meil A, Wojcik J, Legrain P and Gauthier JM

    Hybrigenics SA, 75014 Paris, France. fcolland@hybrigenics.fr

    Access to the human genome facilitates extensive functional proteomics studies. Here, we present an integrated approach combining large-scale protein interaction mapping, exploration of the interaction network, and cellular functional assays performed on newly identified proteins involved in a human signaling pathway. As a proof of principle, we studied the Smad signaling system, which is regulated by members of the transforming growth factor beta (TGFbeta) superfamily. We used two-hybrid screening to map Smad signaling protein-protein interactions and to establish a network of 755 interactions, involving 591 proteins, 179 of which were poorly or not annotated. The exploration of such complex interaction databases is improved by the use of PIMRider, a dedicated navigation tool accessible through the Web. The biological meaning of this network is illustrated by the presence of 18 known Smad-associated proteins. Functional assays performed in mammalian cells including siRNA knock-down experiments identified eight novel proteins involved in Smad signaling, thus validating this integrated functional proteomics approach.

    Genome research 2004;14;7;1324-32

  • 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

  • Identification of neurabin II as a novel doublecortin interacting protein.

    Tsukada M, Prokscha A, Oldekamp J and Eichele G

    Max Planck Institute for Experimental Endocrinology, Feodor-Lynen-Strasse 7, Hannover 30625, Germany.

    The neuronal migration protein doublecortin (DCX) that associates with microtubules through a tandem DCX repeat, is required for the development of the complex architecture of the human cerebral cortex. Using a yeast two-hybrid screen with Dcx as bait, we have isolated neurabin II/spinophilin, an F-actin binding protein known to play a role in dendritic spine formation. The coiled-coil domain of neurabin II binds to a DCX region encompassing the C-terminal portion of the second DCX repeat and the N-terminal portion of the Ser/Pro-rich domain. Immunoprecipitation experiments with brain extracts show that neurabin II and Dcx interact in vivo. Several Dcx constructs that mimic human DCX mutant alleles failed to interact with neurabin II. Since Dcx and neurabin II colocalized in the developing and adult brain, a neurabin II-DCX heterodimer may be involved in neuronal migration and dendritic spine formation.

    Mechanisms of development 2003;120;9;1033-43

  • Regulation of p70 S6 kinase by complex formation between the Rac guanine nucleotide exchange factor (Rac-GEF) Tiam1 and the scaffold spinophilin.

    Buchsbaum RJ, Connolly BA and Feig LA

    Department of Biochemistry, Tufts University School of Medicine, Boston, Massachussetts 02111, USA.

    Tiam1 is a ubiquitous guanine nucleotide exchange factor (GEF) that activates the Rac GTPase. We have shown previously that the N terminus of Tiam1 contributes to the signaling specificity of its downstream target Rac via association with IB2, a scaffold that promotes Rac activation of a p38 kinase cascade. Here we show that the N terminus of Tiam1 can influence Rac signaling specificity in a different way by interaction with spinophilin, a scaffold that binds to p70 S6 kinase, another protein regulated by Rac. In particular, spinophilin binding promotes the plasma membrane localization of Tiam1 and enhances the ability of Tiam1 to activate p70 S6 kinase. In contrast, spinophilin binding suppresses the ability of Tiam to activate Pak1, a different Rac effector. Finally, a mutant spinophilin that cannot bind to Tiam1 suppresses serum-induced p70 S6 kinase activation in cells, suggesting that a Tiam1/spinophilin complex contributes to p70 S6 kinase regulation by extracellular signals. These findings add to a growing body of evidence supporting the concept that some Rac-GEFs not only activate Rac GTPases but also participate in the selection of Rac effector by binding to particular scaffolds that complex with components of specific Rac effector pathways.

    Funded by: NIDDK NIH HHS: P30-DK34928

    The Journal of biological chemistry 2003;278;21;18833-41

  • Phosphorylation of spinophilin modulates its interaction with actin filaments.

    Hsieh-Wilson LC, Benfenati F, Snyder GL, Allen PB, Nairn AC and Greengard P

    Laboratory of Molecular and Cellular Neuroscience, The Rockefeller University, New York, New York 10021, USA.

    Spinophilin is a protein phosphatase 1 (PP1)- and actin-binding protein that modulates excitatory synaptic transmission and dendritic spine morphology. We report that spinophilin is phosphorylated in vitro by protein kinase A (PKA). Phosphorylation of spinophilin was stimulated by treatment of neostriatal neurons with a dopamine D1 receptor agonist or with forskolin, consistent with spinophilin being a substrate for PKA in intact cells. Using tryptic phosphopeptide mapping, site-directed mutagenesis, and microsequencing analysis, we identified two major sites of phosphorylation, Ser-94 and Ser-177, that are located within the actin-binding domain of spinophilin. Phosphorylation of spinophilin by PKA modulated the association between spinophilin and the actin cytoskeleton. Following subcellular fractionation, unphosphorylated spinophilin was enriched in the postsynaptic density, whereas a pool of phosphorylated spinophilin was found in the cytosol. F-actin co-sedimentation and overlay analysis revealed that phosphorylation of spinophilin reduced the stoichiometry of the spinophilin-actin interaction. In contrast, the ability of spinophilin to bind to PP1 remained unchanged. Taken together, our studies suggest that phosphorylation of spinophilin by PKA modulates the anchoring of the spinophilin-PP1 complex within dendritic spines, thereby likely contributing to the efficacy and plasticity of synaptic transmission.

    Funded by: NIDA NIH HHS: DA10044, P01 DA010044; NIMH NIH HHS: MH40899

    The Journal of biological chemistry 2003;278;2;1186-94

  • Neurabins recruit protein phosphatase-1 and inhibitor-2 to the actin cytoskeleton.

    Terry-Lorenzo RT, Elliot E, Weiser DC, Prickett TD, Brautigan DL and Shenolikar S

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

    Inhibitor-2 (I-2) bound protein phosphatase-1 (PP1) and several PP1-binding proteins from rat brain extracts, including the actin-binding proteins, neurabin I and neurabin II. Neurabins from rat brain lysates were sedimented by I-2 and its structural homologue, I-4. The central domain of both neurabins bound PP1 and I-2, and mutation of a conserved PP1-binding motif abolished neurabin binding to both proteins. Microcystin-LR, a PP1 inhibitor, also attenuated I-2 binding to neurabins. Immunoprecipitation of neurabin I established its association with PP1 and I-2 in HEK293T cells and suggested that PP1 mediated I-2 binding to neurabins. The C terminus of I-2, although not required for PP1 binding, facilitated PP1 recruitment by neurabins, which also targeted I-2 to polymerized F-actin. Mutations that attenuated PP1 binding to I-2 and neurabin I suggested distinct and overlapping sites for these two proteins on the PP1 catalytic subunit. Immunocytochemistry in epithelial cells and cultured hippocampal neurons showed that endogenous neurabin II and I-2 colocalized at actin-rich structures, consistent with the ability of neurabins to target the PP1.I-2 complex to actin cytoskeleton and regulate cell morphology.

    Funded by: NIGMS NIH HHS: GM56362; NINDS NIH HHS: NS41063

    The Journal of biological chemistry 2002;277;48;46535-43

  • The actin-binding domain of spinophilin is necessary and sufficient for targeting to dendritic spines.

    Grossman SD, Hsieh-Wilson LC, Allen PB, Nairn AC and Greengard P

    Laboratory of Molecular and Cellular Neuroscience, The Rockefeller University, New York, NY 10021, USA. grossms@rockefeller.edu

    Spinophilin is enriched in dendritic spines, small protrusions of the postsynaptic membrane along the length of the dendrite that contain the majority of excitatory synapses. Spinophilin binds to protein phosphatase 1 with high affinity and targets it to dendritic spines, therefore placing it in proximity to regulate glutamate receptor activity. Spinophilin also binds to and bundles f-actin, the main cytoskeletal constituent of dendritic spines, and may therefore serve to regulate the structure of the synapse. In this study, we sought to determine the structural basis for the targeting of spinophilin to dendritic spines. Our results show that the actin-binding domain of spinophilin is necessary and sufficient for targeting of spinophilin to dendrites and dendritic spines.

    Funded by: NIDA NIH HHS: DA10044, P01 DA010044; NIMH NIH HHS: 2T32MH15125, MH40899

    Neuromolecular medicine 2002;2;1;61-9

  • Agonist-regulated Interaction between alpha2-adrenergic receptors and spinophilin.

    Richman JG, Brady AE, Wang Q, Hensel JL, Colbran RJ and Limbird LE

    Departments of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee 37232-6600, USA.

    Previously, we demonstrated that the third intracellular (3i) loop of the heptahelical alpha2A-adrenergic receptor (alpha2A AR) is critical for retention at the basolateral surface of polarized Madin-Darby canine kidney II (MDCKII) cells following their direct targeting to this surface. Findings that the 3i loops of the D2 dopamine receptors interact with spinophilin (Smith, F. D., Oxford, G. S., and Milgram, S. L. (1999) J. Biol. Chem. 274, 19894-19900) and that spinophilin is enriched beneath the basolateral surface of polarized MDCK cells prompted us to assess whether alpha(2)AR subtypes might also interact with spinophilin. [35S]Met-labeled 3i loops of the alpha2A AR (Val(217)-Ala(377)), alpha2BAR (Lys(210)-Trp(354)), and alpha2CAR (Arg(248)-Val(363)) subtypes interacted with glutathione S-transferase-spinophilin fusion proteins. These interactions could be refined to spinophilin amino acid residues 169-255, in a region between spinophilin's F-actin binding and phosphatase 1 regulatory domains. Furthermore, these interactions occur in intact cells in an agonist-regulated fashion, because alpha2A AR and spinophilin coimmunoprecipitation from cells is enhanced by prior treatment with agonist. These findings suggest that spinophilin may contribute not only to alpha2 AR localization but also to agonist modulation of alpha2AR signaling.

    Funded by: NIDDK NIH HHS: DK43879, T32DK07563; NINDS NIH HHS: NS37508

    The Journal of biological chemistry 2001;276;18;15003-8

  • The human tumor suppressor arf interacts with spinophilin/neurabin II, a type 1 protein-phosphatase-binding protein.

    Vivo M, Calogero RA, Sansone F, Calabrò V, Parisi T, Borrelli L, Saviozzi S and La Mantia G

    Department of Genetics, General and Molecular Biology, University of Naples "Federico II," via Mezzocannone 8, Napoli 80134, Italy.

    The INK4a gene, one of the most often disrupted loci in human cancer, encodes two unrelated proteins, p16(INK4a) and p14(ARF) (ARF) both capable of inducing cell cycle arrest. Although it has been clearly demonstrated that ARF inhibits cell cycle via p53 stabilization, very little is known about the involvement of ARF in other cell cycle regulatory pathways, as well as on the mechanisms responsible for activating ARF following oncoproliferative stimuli. In search of factors that might associate with ARF to control its activity or its specificity, we performed a yeast two-hybrid screen. We report here that the human homologue of spinophilin/neurabin II, a regulatory subunit of protein phosphatase 1 catalytic subunit specifically interacts with ARF, both in yeast and in mammalian cells. We also show that ectopic expression of spinophilin/neurabin II inhibits the formation of G418-resistant colonies when transfected into human and mouse cell lines, regardless of p53 and ARF status. Moreover, spinophilin/ARF coexpression in Saos-2 cells, where ARF ectopic expression is ineffective, somehow results in a synergic effect. These data demonstrate a role for spinophilin in cell growth and suggest that ARF and spinophilin could act in partially overlapping pathways.

    The Journal of biological chemistry 2001;276;17;14161-9

  • Direct interaction of the trans-Golgi network membrane protein, TGN38, with the F-actin binding protein, neurabin.

    Stephens DJ and Banting G

    Department of Biochemistry, University of Bristol, School of Medical Sciences, University Walk, Bristol BS8 1TD, United Kingdom.

    TGN38 is a type I integral membrane protein that constitutively cycles between the trans-Golgi network (TGN) and plasma membrane. The cytosolic domain of TGN38 interacts with AP2 clathrin adaptor complexes via the tyrosine-containing motif (-SDYQRL-) to direct internalization from the plasma membrane. This motif has previously been shown to direct both internalization and subsequent TGN targeting of TGN38. We have used the cytosolic domain of TGN38 in a two-hybrid screen, and we have identified the brain-specific F-actin binding protein neurabin-I as a TGN38-binding protein. We demonstrate a direct interaction between TGN38 and the ubiquitous homologue of neurabin-I, neurabin-II (also called spinophilin). We have used a combination of yeast two-hybrid and in vitro protein interaction assays to show that this interaction is dependent on the serine (but not tyrosine) residue of the known TGN38 trafficking motif. We show that TGN38 interacts with the coiled coil region of neurabin in vitro and binds preferentially with the dimeric form of neurabin. TGN38 and neurabin also interact in vivo as demonstrated by coimmunoprecipitation from stably transfected PC12 cells. These data suggest that neurabin provides a direct physical link between TGN38-containing membranes and the actin cytoskeleton.

    The Journal of biological chemistry 1999;274;42;30080-6

  • Association of the D2 dopamine receptor third cytoplasmic loop with spinophilin, a protein phosphatase-1-interacting protein.

    Smith FD, Oxford GS and Milgram SL

    Department of Cell and Molecular Physiology and the Curriculum in Neurobiology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA.

    Signaling through D2 class dopamine receptors is crucial to correct brain development and function, and dysfunction of this system is implicated in major neurological disorders such as Parkinson's disease and schizophrenia. To investigate potential novel mechanisms of D2 receptor regulation, the third cytoplasmic loop of the D2 dopamine receptor was used to screen a rat hippocampal yeast two-hybrid library. Spinophilin, a recently characterized F-actin and protein phosphatase-1-binding protein with a single PDZ domain was identified as a protein that specifically associates with this region of D2 receptors. A direct interaction between spinophilin and the D2 receptor was confirmed in vitro using recombinant fusion proteins. The portion of spinophilin responsible for interacting with the D2 third cytoplasmic loop was narrowed to a region that does not include the actin-binding domain, the PDZ domain, or the coiled-coil. This region is distinct from the site of interaction with protein phosphatase-1, and both D2 receptors and protein phosphatase-1 may bind spinophilin at the same time. The interaction is not mediated via the unique 29-amino acid insert in D2long; both D2long and D2short third cytoplasmic loops interact with spinophilin in vitro and in yeast two-hybrid assays. Expression of D2 receptors containing an extracellular hemagglutinin epitope in Madin-Darby canine kidney cells results in co-localization of receptor and endogenous spinophilin as determined by immunocytochemistry using antibodies directed against spinophilin and the HA tag. We hypothesize that spinophilin is important for establishing a signaling complex for dopaminergic neurotransmission through D2 receptors by linking receptors to downstream signaling molecules and the actin cytoskeleton.

    Funded by: NIDDK NIH HHS: R29DK50744; NINDS NIH HHS: NS18788

    The Journal of biological chemistry 1999;274;28;19894-900

  • Characterization of the neuronal targeting protein spinophilin and its interactions with protein phosphatase-1.

    Hsieh-Wilson LC, Allen PB, Watanabe T, Nairn AC and Greengard P

    Laboratory of Molecular and Cellular Neuroscience, The Rockefeller University, New York 10021, USA. hsiehl@rockvax.rockefeller.edu

    Protein phosphatase-1 (PP1) plays an important role in a variety of cellular processes, including muscle contraction, cell-cycle progression, and neurotransmission. The localization and substrate specificity of PP1 are determined by a class of proteins known as targeting subunits. In the present study, the interaction between PP1 and spinophilin, a neuronal protein that targets PP1 to dendritic spines, has been characterized. Deletion analysis revealed that a high-affinity binding domain is located within residues 417-494 of spinophilin. This domain contains a pentapeptide motif (R/K-R/K-V/I-X-F) between amino acids 447 and 451 (R-K-I-H-F) that is conserved in other PP1 regulatory subunits. Mutation of phenylalanine-451 (F451A) or deletion of the conserved motif abolished the ability of spinophilin to bind PP1, as observed by coprecipitation, overlay, and competition binding assays. In addition, deletion of regions 417-442 or 474-494, either singly or in combination, impaired the ability of spinophilin to coprecipitate PP1. A comparison of the binding and inhibitory properties of spinophilin peptides suggested that distinct subdomains of spinophilin are responsible for binding and modulating PP1 activity. Mutational analysis of the modulatory subdomain revealed that spinophilin interacts with PP1 via a mechanism unlike those used by the cytosolic inhibitors DARPP-32 (dopamine- and cAMP-regulated phosphoprotein, Mr 32 000) and inhibitor-1. Finally, characterization of the interactions between spinophilin and PP1 has facilitated the design of peptide antagonists capable of disrupting spinophilin-PP1 interactions. These studies support the notion that spinophilin functions in vivo as a neuronal PP1 targeting subunit by directing the enzyme to postsynaptic densities and regulating its activity toward physiological substrates.

    Funded by: NIDA NIH HHS: DA10044, P01 DA010044; NIMH NIH HHS: MH40899

    Biochemistry 1999;38;14;4365-73

  • Neurabin is a synaptic protein linking p70 S6 kinase and the neuronal cytoskeleton.

    Burnett PE, Blackshaw S, Lai MM, Qureshi IA, Burnett AF, Sabatini DM and Snyder SH

    Department of Neuroscience, The Johns Hopkins School of Medicine, Baltimore, MD 21205, USA.

    p70 S6 kinase (p70(S6k)) is a mitogen-activated protein kinase that plays a central role in the control of mRNA translation. It physiologically phosphorylates the S6 protein of the 40s ribosomal subunit in response to mitogenic stimuli and is a downstream component of the rapamycin-sensitive pathway, which includes the 12-kDa FK506 binding protein and includes rapamycin and the 12-kDa FK506 binding protein target 1. Here, we report the identification of neurabin (neural tissue-specific F-actin binding protein), a neuronally enriched protein of 1,095 amino acids that contains a PDZ domain and binds p70(S6k). We demonstrate the neurabin-p70(S6k) interaction by yeast two-hybrid analysis and biochemical techniques. p70(S6k) and neurabin coimmunoprecipitate from transfected HEK293 cells. Site-directed mutagenesis of neurabin implicates its PDZ domain in the interaction with p70(S6k), and deletion of the carboxyl-terminal five amino acids of p70(S6k) abrogates the interaction. Cotransfection of neurabin in HEK293 cells activates p70(S6k) kinase activity. The mRNA of neurabin and p70(S6k) show striking colocalization in brain sections by in situ hybridization. Subcellular fractionation of rat brain demonstrates that neurabin and p70(S6k) both localize to the soluble fraction of synaptosomes. By way of its PDZ domain, the neuronal-specific neurabin may target p70(S6k) to nerve terminals.

    Funded by: NIDA NIH HHS: DA-00074, K05 DA000074; NIGMS NIH HHS: GM-07309, T32 GM007309; NIMH NIH HHS: MH-18501, R01 MH018501, R37 MH018501

    Proceedings of the National Academy of Sciences of the United States of America 1998;95;14;8351-6

  • Spinophilin, a novel protein phosphatase 1 binding protein localized to dendritic spines.

    Allen PB, Ouimet CC and Greengard P

    Laboratory of Molecular and Cellular Neuroscience, The Rockefeller University, 1230 York Avenue, New York, NY 10021, USA.

    Dendritic spines receive the vast majority of excitatory synaptic contacts in the mammalian brain and are presumed to contain machinery for the integration of various signal transduction pathways. Protein phosphatase 1 (PP1) is greatly enriched in dendritic spines and has been implicated in both the regulation of ionic conductances and long-term synaptic plasticity. The molecular mechanism whereby PP1 is localized to spines is unknown. We have now characterized a novel protein that forms a complex with the catalytic subunit of PP1 and is a potent modulator of PP1 enzymatic activity in vitro. Within the brain this protein displays a remarkably distinct localization to the heads of dendritic spines and has therefore been named spinophilin. Spinophilin has the properties expected of a scaffolding protein localized to the cell membrane and contains a single consensus sequence in PSD95/DLG/zo-1, which implies cross-linking of PP1 to transmembrane protein complexes. We propose that spinophilin represents a novel targeting subunit for PP1, which directs the enzyme to those substrates in the dendritic spine compartment, e.g., neurotransmitter receptors, which mediate the regulation of synaptic function by PP1.

    Funded by: NIDA NIH HHS: DA 10044, P01 DA010044; NIMH NIH HHS: MH 40899, P01 MH040899

    Proceedings of the National Academy of Sciences of the United States of America 1997;94;18;9956-61

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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