201
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Emaduddin M, Edelmann MJ, Kessler BM, Feller SM. Odin (ANKS1A) is a Src family kinase target in colorectal cancer cells. Cell Commun Signal 2008; 6:7. [PMID: 18844995 PMCID: PMC2584000 DOI: 10.1186/1478-811x-6-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2008] [Accepted: 10/09/2008] [Indexed: 11/25/2022] Open
Abstract
Background Src family kinases (SFK) are implicated in the development of some colorectal cancers (CRC). One SFK member, Lck, is not detectable in normal colonic epithelium, but becomes aberrantly expressed in a subset of CRCs. Although SFK have been extensively studied in fibroblasts and different types of immune cells, their physical and functional targets in many epithelial cancers remain poorly characterised. Results 64 CRC cell lines were tested for expression of Lck. SW620 CRC cells, which express high levels of Lck and also contain high basal levels of tyrosine phosphorylated (pY) proteins, were then analysed to identify novel SFK targets. Since SH2 domains of SFK are known to often bind substrates after phosphorylation by the kinase domain, the LckSH2 was compared with 14 other SH2s for suitability as affinity chromatography reagent. Mass spectrometric analyses of LckSH2-purified pY proteins subsequently identified several proteins readily known as SFK kinase substrates, including cortactin, Tom1L1 (SRCASM), GIT1, vimentin and AFAP1L2 (XB130). Additional proteins previously reported as substrates of other tyrosine kinase were also detected, including the EGF and PDGF receptor target Odin. Odin was further analysed and found to contain substantially less pY upon inhibition of SFK activity in SW620 cells, indicating that it is a formerly unknown SFK target in CRC cells. Conclusion Rapid identification of known and novel SFK targets in CRC cells is feasible with SH2 domain affinity chromatography. The elucidation of new SFK targets like Odin in epithelial cancer cells is expected to lead to novel insight into cancer cell signalling mechanisms and may also serve to indicate new biomarkers for monitoring tumor cell responses to drug treatments.
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Affiliation(s)
- Muhammad Emaduddin
- Cell Signalling Group, Department of Molecular Oncology, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Oxford University, Headley Way, Oxford OX3 9DS, UK.
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202
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Langenick J, Araki T, Yamada Y, Williams JG. A Dictyostelium homologue of the metazoan Cbl proteins regulates STAT signalling. J Cell Sci 2008; 121:3524-30. [PMID: 18840649 DOI: 10.1242/jcs.036798] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Cbl proteins downregulate metazoan signalling pathways by ubiquitylating receptor tyrosine kinases, thereby targeting them for degradation. They contain a phosphotyrosine-binding region, comprising an EF-hand and an SH2 domain, linked to an E3 ubiquitin-ligase domain. CblA, a Dictyostelium homologue of the Cbl proteins, contains all three conserved domains. In a cblA(-) strain early development occurs normally but migrating cblA(-) slugs frequently fragment and the basal disc of the culminants that are formed are absent or much reduced. These are characteristic features of mutants in signalling by DIF-1, the low-molecular-mass prestalk and stalk cell inducer. Tyrosine phosphorylation of STATc is induced by DIF-1 but in the cblA(-) strain this response is attenuated relative to parental cells. We present evidence that CblA fulfils this function, as a positive regulator of STATc tyrosine phosphorylation, by downregulating PTP3, the protein tyrosine phosphatase responsible for dephosphorylating STATc. Thus Cbl proteins have an ancient origin but, whereas metazoan Cbl proteins regulate tyrosine kinases, the Dictyostelium Cbl regulates via a tyrosine phosphatase.
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Affiliation(s)
- Judith Langenick
- University of Dundee, School of Life Sciences, Dow Street, Dundee DD1 5EH, UK
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203
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Ren S, Uversky VN, Chen Z, Dunker AK, Obradovic Z. Short Linear Motifs recognized by SH2, SH3 and Ser/Thr Kinase domains are conserved in disordered protein regions. BMC Genomics 2008; 9 Suppl 2:S26. [PMID: 18831792 PMCID: PMC2559891 DOI: 10.1186/1471-2164-9-s2-s26] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Background Protein interactions are essential for most cellular functions. Interactions mediated by domains that appear in a large number of proteins are of particular interest since they are expected to have an impact on diversities of cellular processes such as signal transduction and immune response. Many well represented domains recognize and bind to primary sequences less than 10 amino acids in length called Short Linear Motifs (SLiMs). Results In this study, we systematically studied the evolutionary conservation of SLiMs recognized by SH2, SH3 and Ser/Thr Kinase domains in both ordered and disordered protein regions. Disordered protein regions are protein sequences that lack a fixed three-dimensional structure under putatively native conditions. We find that, in all these domains examined, SLiMs are more conserved in disordered regions. This trend is more evident in those protein functional groups that are frequently reported to interact with specific domains. Conclusion The correlation between SLiM conservation with disorder prediction demonstrates that functional SLiMs recognized by each domain occur more often in disordered as compared to structured regions of proteins.
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Affiliation(s)
- Siyuan Ren
- Center for Information Science and Technology, Temple University, Philadelphia, PA 19122, USA.
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204
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Miller ML, Jensen LJ, Diella F, Jørgensen C, Tinti M, Li L, Hsiung M, Parker SA, Bordeaux J, Sicheritz-Ponten T, Olhovsky M, Pasculescu A, Alexander J, Knapp S, Blom N, Bork P, Li S, Cesareni G, Pawson T, Turk BE, Yaffe MB, Brunak S, Linding R. Linear motif atlas for phosphorylation-dependent signaling. Sci Signal 2008; 1:ra2. [PMID: 18765831 DOI: 10.1126/scisignal.1159433] [Citation(s) in RCA: 365] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Systematic and quantitative analysis of protein phosphorylation is revealing dynamic regulatory networks underlying cellular responses to environmental cues. However, matching these sites to the kinases that phosphorylate them and the phosphorylation-dependent binding domains that may subsequently bind to them remains a challenge. NetPhorest is an atlas of consensus sequence motifs that covers 179 kinases and 104 phosphorylation-dependent binding domains [Src homology 2 (SH2), phosphotyrosine binding (PTB), BRCA1 C-terminal (BRCT), WW, and 14-3-3]. The atlas reveals new aspects of signaling systems, including the observation that tyrosine kinases mutated in cancer have lower specificity than their non-oncogenic relatives. The resource is maintained by an automated pipeline, which uses phylogenetic trees to structure the currently available in vivo and in vitro data to derive probabilistic sequence models of linear motifs. The atlas is available as a community resource (http://netphorest.info).
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Affiliation(s)
- Martin Lee Miller
- Center for Biological Sequence Analysis, Technical University of Denmark, 2800 Lyngby, Denmark
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205
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Abstract
CudA, a nuclear protein required for Dictyostelium prespore-specific gene expression, binds in vivo to the promoter of the cotC prespore gene. A 14 nucleotide region of the cotC promoter binds CudA in vitro and ECudA, an Entamoeba CudA homologue, also binds to this site. The CudA and ECudA DNA-binding sites contain a dyad and, consistent with a symmetrical binding site, CudA forms a homodimer in the yeast two-hybrid system. Mutation of CudA binding sites within the cotC promoter reduces expression from cotC in prespore cells. The CudA and ECudA proteins share a 120 amino acid core of homology, and clustered point mutations introduced into two highly conserved motifs within the ECudA core region decrease its specific DNA binding in vitro. This region, the presumptive DNA-binding domain, is similar in sequence to domains in two Arabidopsis proteins and one Oryza protein. Significantly, these are the only proteins in the two plant species that contain an SH2 domain. Such a structure, with a DNA-binding domain located upstream of an SH2 domain, suggests that the plant proteins are orthologous to metazoan STATs. Consistent with this notion, the DNA sequence of the CudA half site, GAA, is identical to metazoan STAT half sites, although the relative positions of the two halves of the dyad are reversed. These results define a hitherto unrecognised class of transcription factors and suggest a model for the evolution of STATs and their DNA-binding sites.
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Affiliation(s)
| | | | - Masashi Fukuzawa
- School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
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206
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Affiliation(s)
- Bruce J Mayer
- Raymond and Beverly Sackler Laboratory of Genetics and Molecular Medicine, Department of Genetics and Developmental Biology, University of Connecticut Health Center, Farmington, CT 06030, USA.
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207
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The protist, Monosiga brevicollis, has a tyrosine kinase signaling network more elaborate and diverse than found in any known metazoan. Proc Natl Acad Sci U S A 2008; 105:9674-9. [PMID: 18621719 DOI: 10.1073/pnas.0801314105] [Citation(s) in RCA: 178] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Tyrosine kinase signaling has long been considered a hallmark of intercellular communication, unique to multicellular animals. Our genomic analysis of the unicellular choanoflagellate Monosiga brevicollis discovers a remarkable count of 128 tyrosine kinases, 38 tyrosine phosphatases, and 123 phosphotyrosine (pTyr)-binding SH2 proteins, all higher counts than seen in any metazoan. This elaborate signaling network shows little orthology to metazoan counterparts yet displays many innovations reminiscent of metazoans. These include extracellular domains structurally related to those of metazoan receptor kinases, alternative methods for membrane anchoring and phosphotyrosine interaction in cytoplasmic kinases, and domain combinations that link kinases to small GTPase signaling and transcription. These proteins also display a wealth of combinations of known signaling domains. This uniquely divergent and elaborate signaling network illuminates the early evolution of pTyr signaling, explores innovative ways to traverse the cellular signaling circuitry, and shows extensive convergent evolution, highlighting pervasive constraints on pTyr signaling.
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208
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Granum S, Andersen TCB, Sørlie M, Jørgensen M, Koll L, Berge T, Lea T, Fleckenstein B, Spurkland A, Sundvold-Gjerstad V. Modulation of Lck function through multisite docking to T cell-specific adapter protein. J Biol Chem 2008; 283:21909-19. [PMID: 18541536 DOI: 10.1074/jbc.m800871200] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
T cell-specific adapter protein (TSAd), encoded by the SH2D2A gene, interacts with Lck through its C terminus and thus modulates Lck activity. Here we mapped Lck phosphorylation and interaction sites on TSAd and evaluated their functional importance. The three C-terminal TSAd tyrosines Tyr(280), Tyr(290), and Tyr(305) were phosphorylated by Lck and functioned as docking sites for the Lck Src homology 2 (SH2) domain. Binding affinities of the TSAd Tyr(P)(280) and Tyr(P)(290) phosphopeptides to the isolated Lck SH2 domain were similar to that observed for the Lck Tyr(P)(505) phosphopeptide, whereas the TSAd Tyr(P)(305) peptide displayed a 10-fold higher affinity. The proline-rich Lck SH3-binding site on TSAd as well as the Lck SH2 domain were required for efficient tyrosine phosphorylation of TSAd by Lck. Interaction sites on TSAd for both Lck SH2 and Lck SH3 were necessary for TSAd-mediated modulation of proximal TCR signaling events. We found that 20-30% of TSAd molecules are phosphorylated in activated T cells and that the proportion of TSAd to Lck molecules in such cells is approximately 1:1. Therefore, in activated T cells, a considerable number of Lck molecules may potentially be engaged by TSAd. In conclusion, Lck binds to TSAd prolines and phosphorylates and interacts with the three C-terminal TSAd tyrosines. We propose that through multivalent interactions with Lck, TSAd diverts Lck from phosphorylating other substrates, thus modulating its functional activity through substrate competition.
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Affiliation(s)
- Stine Granum
- Department of Anatomy, Institute of Basic Medical Sciences, University of Oslo, Box 1105, Blindern, N-0317 Oslo, Norway.
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209
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Li L, Wu C, Huang H, Zhang K, Gan J, Li SSC. Prediction of phosphotyrosine signaling networks using a scoring matrix-assisted ligand identification approach. Nucleic Acids Res 2008; 36:3263-73. [PMID: 18424801 PMCID: PMC2425477 DOI: 10.1093/nar/gkn161] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Systematic identification of binding partners for modular domains such as Src homology 2 (SH2) is important for understanding the biological function of the corresponding SH2 proteins. We have developed a worldwide web-accessible computer program dubbed SMALI for scoring matrix-assisted ligand identification for SH2 domains and other signaling modules. The current version of SMALI harbors 76 unique scoring matrices for SH2 domains derived from screening oriented peptide array libraries. These scoring matrices are used to search a protein database for short peptides preferred by an SH2 domain. An experimentally determined cut-off value is used to normalize an SMALI score, therefore allowing for direct comparison in peptide-binding potential for different SH2 domains. SMALI employs distinct scoring matrices from Scansite, a popular motif-scanning program. Moreover, SMALI contains built-in filters for phosphoproteins, Gene Ontology (GO) correlation and colocalization of subject and query proteins. Compared to Scansite, SMALI exhibited improved accuracy in identifying binding peptides for SH2 domains. Applying SMALI to a group of SH2 domains identified hundreds of interactions that overlap significantly with known networks mediated by the corresponding SH2 proteins, suggesting SMALI is a useful tool for facile identification of signaling networks mediated by modular domains that recognize short linear peptide motifs.
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Affiliation(s)
- Lei Li
- Department of Biochemistry and the Siebens-Drake Medical Research Institute, University of Western Ontario, London, Ontario N6A 5C1, Canada
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210
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Miller ML, Hanke S, Hinsby AM, Friis C, Brunak S, Mann M, Blom N. Motif decomposition of the phosphotyrosine proteome reveals a new N-terminal binding motif for SHIP2. Mol Cell Proteomics 2008; 7:181-92. [PMID: 17938406 DOI: 10.1074/mcp.m700241-mcp200] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Advances in mass spectrometry-based proteomics have yielded a substantial mapping of the tyrosine phosphoproteome and thus provided an important step toward a systematic analysis of intracellular signaling networks in higher eukaryotes. In this study we decomposed an uncharacterized proteomics data set of 481 unique phosphotyrosine (Tyr(P)) peptides by sequence similarity to known ligands of the Src homology 2 (SH2) and the phosphotyrosine binding (PTB) domains. From 20 clusters we extracted 16 known and four new interaction motifs. Using quantitative mass spectrometry we pulled down Tyr(P)-specific binding partners for peptides corresponding to the extracted motifs. We confirmed numerous previously known interaction motifs and found 15 new interactions mediated by phosphosites not previously known to bind SH2 or PTB. Remarkably, a novel hydrophobic N-terminal motif ((L/V/I)(L/V/I)pY) was identified and validated as a binding motif for the SH2 domain-containing inositol phosphatase SHIP2. Our decomposition of the in vivo Tyr(P) proteome furthermore suggests that two-thirds of the Tyr(P) sites mediate interaction, whereas the remaining third govern processes such as enzyme activation and nucleic acid binding.
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Affiliation(s)
- Martin Lee Miller
- Center for Biological Sequence Analysis, Technical University of Denmark, Kemitorvet, Building 208, DK-2800 Lyngby, Denmark
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211
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Ng C, Jackson RA, Buschdorf JP, Sun Q, Guy GR, Sivaraman J. Structural basis for a novel intrapeptidyl H-bond and reverse binding of c-Cbl-TKB domain substrates. EMBO J 2008; 27:804-16. [PMID: 18273061 DOI: 10.1038/emboj.2008.18] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2007] [Accepted: 01/17/2008] [Indexed: 12/21/2022] Open
Abstract
The c-Cbl tyrosine kinase binding domain (Cbl-TKB), essentially an 'embedded' SH2 domain, has a critical role in targeting proteins for ubiquitination. To address how this domain can bind to disparate recognition mofits and to determine whether this results in variations in substrate-binding affinity, we compared crystal structures of the Cbl-TKB domain complexed with phosphorylated peptides of Sprouty2, Sprouty4, epidermal growth factor receptor, Syk, and c-Met receptors and validated the binding with point-mutational analyses using full-length proteins. An obligatory, intrapeptidyl H-bond between the phosphotyrosine and the conserved asparagine or adjacent arginine is essential for binding and orients the peptide into a positively charged pocket on c-Cbl. Surprisingly, c-Met bound to Cbl in the reverse direction, which is unprecedented for SH2 domain binding. The necessity of this intrapeptidyl H-bond was confirmed with isothermal titration calorimetry experiments that also showed Sprouty2 to have the highest binding affinity to c-Cbl; this may enable the selective sequestration of c-Cbl from other target proteins.
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Affiliation(s)
- Cherlyn Ng
- Department of Biological Sciences, National University of Singapore, Singapore
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212
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Zhang Y, Zhou S, Wavreille AS, DeWille J, Pei D. Cyclic peptidyl inhibitors of Grb2 and tensin SH2 domains identified from combinatorial libraries. ACTA ACUST UNITED AC 2008; 10:247-55. [PMID: 18257540 DOI: 10.1021/cc700185g] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cyclic peptides provide attractive lead compounds for drug discovery and excellent molecular probes in biomedical research. In this work, a novel method has been developed for the high-throughput synthesis, screening, and identification of cyclic peptidyl ligands against macromolecular targets. Support-bound cyclic phosphotyrosyl peptide libraries containing randomized amino acid sequences and different ring sizes (theoretical diversity of 3.2 x 10(6)) were synthesized and screened against the SH2 domains of Grb2 and tensin. Potent, selective inhibitors were identified from the libraries and were generally more effective than the corresponding linear peptides. One of the inhibitors selected against the Grb2 SH2 domain inhibited human breast cancer cell growth and disrupted actin filaments. This method should be applicable to the development of cyclic peptidyl inhibitors against other protein domains, enzymes, and receptors.
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Affiliation(s)
- Yanyan Zhang
- Department of Chemistry and Ohio State Biochemistry Program, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, USA
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213
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Huang H, Li L, Wu C, Schibli D, Colwill K, Ma S, Li C, Roy P, Ho K, Songyang Z, Pawson T, Gao Y, Li SSC. Defining the specificity space of the human SRC homology 2 domain. Mol Cell Proteomics 2007; 7:768-84. [PMID: 17956856 DOI: 10.1074/mcp.m700312-mcp200] [Citation(s) in RCA: 171] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Src homology 2 (SH2) domains are the largest family of interaction modules encoded by the human genome to recognize tyrosine-phosphorylated sequences and thereby play pivotal roles in transducing and controlling cellular signals emanating from protein-tyrosine kinases. Different SH2 domains select for distinct phosphopeptides, and the function of a given SH2 domain is often dictated by the specific motifs that it recognizes. Therefore, deciphering the phosphotyrosyl peptide motif recognized by an SH2 domain is the key to understanding its cellular function. Here we cloned all 120 SH2 domains identified in the human genome and determined the phosphotyrosyl peptide binding properties of 76 SH2 domains by screening an oriented peptide array library. Of these 76, we defined the selectivity for 43 SH2 domains and refined the binding motifs for another 33 SH2 domains. We identified a number of novel binding motifs, which are exemplified by the BRDG1 SH2 domain that selects specifically for a bulky, hydrophobic residue at P + 4 relative to the Tyr(P) residue. Based on the oriented peptide array library data, we developed scoring matrix-assisted ligand identification (or SMALI), a Web-based program for predicting binding partners for SH2-containing proteins. When applied to SH2D1A/SAP (SLAM-associated protein), a protein whose mutation or deletion underlies the X-linked lymphoproliferative syndrome, SMALI not only recapitulated known interactions but also identified a number of novel interacting proteins for this disease-associated protein. SMALI also identified a number of potential interactors for BRDG1, a protein whose function is largely unknown. Peptide in-solution binding analysis demonstrated that a SMALI score correlates well with the binding energy of a peptide to a given SH2 domain. The definition of the specificity space of the human SH2 domain provides both the necessary molecular basis and a platform for future exploration of the functions for SH2-containing proteins in cells.
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Affiliation(s)
- Haiming Huang
- Department of Biochemistry, Siebens-Drake Medical Research Institute, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario N6A 5C1, Canada
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214
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Glassmann A, Molly S, Surchev L, Nazwar TA, Holst M, Hartmann W, Baader SL, Oberdick J, Pietsch T, Schilling K. Developmental expression and differentiation-related neuron-specific splicing of metastasis suppressor 1 (Mtss1) in normal and transformed cerebellar cells. BMC DEVELOPMENTAL BIOLOGY 2007; 7:111. [PMID: 17925019 PMCID: PMC2194783 DOI: 10.1186/1471-213x-7-111] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2007] [Accepted: 10/09/2007] [Indexed: 02/02/2023]
Abstract
Background Mtss1 encodes an actin-binding protein, dysregulated in a variety of tumors, that interacts with sonic hedgehog/Gli signaling in epidermal cells. Given the prime importance of this pathway for cerebellar development and tumorigenesis, we assessed expression of Mtss1 in the developing murine cerebellum and human medulloblastoma specimens. Results During development, Mtss1 is transiently expressed in granule cells, from the time point they cease to proliferate to their synaptic integration. It is also expressed by granule cell precursor-derived medulloblastomas. In the adult CNS, Mtss1 is found exclusively in cerebellar Purkinje cells. Neuronal differentiation is accompanied by a switch in Mtss1 splicing. Whereas immature granule cells express a Mtss1 variant observed also in peripheral tissues and comprising exon 12, this exon is replaced by a CNS-specific exon, 12a, in more mature granule cells and in adult Purkinje cells. Bioinformatic analysis of Mtss1 suggests that differential exon usage may affect interaction with Fyn and Src, two tyrosine kinases previously recognized as critical for cerebellar cell migration and histogenesis. Further, this approach led to the identification of two evolutionary conserved nuclear localization sequences. These overlap with the actin filament binding site of Mtss1, and one also harbors a potential PKA and PKC phosphorylation site. Conclusion Both the pattern of expression and splicing of Mtss1 is developmentally regulated in the murine cerebellum. These findings are discussed with a view on the potential role of Mtss1 for cytoskeletal dynamics in developing and mature cerebellar neurons.
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Affiliation(s)
- Alexander Glassmann
- Anatomisches Institut, Anatomie & Zellbiologie, University of Bonn, Bonn, Germany.
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215
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Shvartsman DE, Donaldson JC, Diaz B, Gutman O, Martin GS, Henis YI. Src kinase activity and SH2 domain regulate the dynamics of Src association with lipid and protein targets. ACTA ACUST UNITED AC 2007; 178:675-86. [PMID: 17698610 PMCID: PMC2064473 DOI: 10.1083/jcb.200701133] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Src functions depend on its association with the plasma membrane and with specific membrane-associated assemblies. Many aspects of these interactions are unclear. We investigated the functions of kinase, SH2, and SH3 domains in Src membrane interactions. We used FRAP beam-size analysis in live cells expressing a series of c-Src–GFP proteins with targeted mutations in specific domains together with biochemical experiments to determine whether the mutants can generate and bind to phosphotyrosyl proteins. Wild-type Src displays lipid-like membrane association, whereas constitutively active Src-Y527F interacts transiently with slower-diffusing membrane-associated proteins. These interactions require Src kinase activity and SH2 binding, but not SH3 binding. Furthermore, overexpression of paxillin, an Src substrate with a high cytoplasmic population, competes with membrane phosphotyrosyl protein targets for binding to activated Src. Our observations indicate that the interactions of Src with lipid and protein targets are dynamic and that the kinase and SH2 domain cooperate in the membrane targeting of Src.
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Affiliation(s)
- Dmitry E Shvartsman
- Department of Neurobiochemistry, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
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216
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Perchonock CE, Pajerowski AG, Nguyen C, Shapiro MJ, Shapiro VS. The related adaptors, adaptor in lymphocytes of unknown function X and Rlk/Itk-binding protein, have nonredundant functions in lymphocytes. THE JOURNAL OF IMMUNOLOGY 2007; 179:1768-75. [PMID: 17641043 DOI: 10.4049/jimmunol.179.3.1768] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Adaptors play a critical role in regulating signaling pathways that control lymphocyte development and activation. Adaptor in lymphocytes of unknown function X (ALX) and Rlk/Itk-binding protein (RIBP) are adaptors related by structure and sequence, coexpressed in T cells. Mice deficient for each adaptor demonstrated that ALX and RIBP, respectively, negatively and positively regulate T cell activation in response to TCR/CD28 stimulation. However, these results did not preclude that they may function redundantly in other cell populations, or in response to other stimuli. Therefore, to understand the relationship between these related adaptors, ALX/RIBP-deficient mice were generated. We demonstrate that although ALX and RIBP are expressed throughout T cell development, T cell development occurs normally in these mice. Using the H-Y TCR transgenic model, positive and negative selection were found to proceed unimpeded in the absence of ALX and RIBP. We demonstrate that RIBP is also expressed in B cells; however, RIBP- and ALX/RIBP-deficient mice had normal B cell development, and responded equivalently to wild type in response to IgM, CD40, B cell-activating factor/B lymphocyte stimulator, CpG, and LPS. Interestingly, T cells deficient in both ALX and RIBP behaved similarly to those deficient in ALX alone during T cell activation in response to TCR/CD28, exhibiting increased IL-2 production, CD25 expression, and proliferation, thus showing that ALX deficiency masked the effect of RIBP deficiency. ALX/RIBP-deficient T cells did not have any alterations in either activation-induced cell death or Th1/2 polarization. Therefore, we did not find any functional redundancy or synergy during lymphocyte development, selection, activation, or survival in ALX/RIBP-deficient mice, demonstrating that these molecules function independently.
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Affiliation(s)
- Claire E Perchonock
- Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
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217
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Ingley E. Src family kinases: regulation of their activities, levels and identification of new pathways. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2007; 1784:56-65. [PMID: 17905674 DOI: 10.1016/j.bbapap.2007.08.012] [Citation(s) in RCA: 244] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2007] [Revised: 08/15/2007] [Accepted: 08/15/2007] [Indexed: 01/29/2023]
Abstract
While the Src family of protein tyrosine kinases (SFK), and the main ancillary molecules involved in their regulation, have been studied for many years, the details of their interplay are not fully understood and thus remain under active investigation. Additionally, new players that coordinate their regulation and direct their signalling cascades are also being uncovered, shedding new light on the complexity of these signalling networks. Through the utilization of novel interaction assays, several new interconnecting mediators that are helping to show the elegance of Src family kinase regulation have been discovered. This review outlines SFK regulation, the discovery of the Csk binding protein (Phosphoprotein Associated with Glycosphingolipid-enriched microdomains, Cbp/PAG), and its role in regulating SFK kinase activity status, as well as protein levels. Further, details of the methods used to identify this dual mode of regulation can be applied to delineate the full gamut of SH2/SH3-directed SFK pathways and, indeed, those of any tyrosine kinase. Using Lyn as a model SFK, we and others have shown that Cbp recruits negative regulators of COOH-terminal Src kinase (Csk)/Csk-like protein-tyrosine kinase (Ctk) after Lyn is activated and bound to Cbp. Lyn phosphorylates Cbp on multiple tyrosine residues, including two that can bind Lyn's SH2 domain with high affinity. Lyn also phosphorylates Y314, which recruits Csk/Ctk to phosphorylate Lyn at its Y508 negative site, allowing an inactive conformation to form. However, the pY508 site has a low affinity for Lyn's SH2 domain, while the Cbp sites have high affinity. Thus, until these Cbp sites are dephosphorylated, Lyn can remain active. Intriguingly, phosphorylated Y314 also binds the suppressor of cytokine signalling 1 (SOCS1), resulting in elevated ubiquitination and degradation of Lyn. Thus, a single phosphotyrosine residue within Cbp co-ordinates a two-phase process involving distinct negative regulatory pathways that allow inactivation, followed by degradation, of SFKs.
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Affiliation(s)
- Evan Ingley
- Cell Signalling Group, Laboratory for Cancer Medicine, Western Australian Institute for Medical Research and Centre for Medical Research, The University of Western Australia, Perth, WA, Australia.
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218
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Machida K, Thompson CM, Dierck K, Jablonowski K, Kärkkäinen S, Liu B, Zhang H, Nash PD, Newman DK, Nollau P, Pawson T, Renkema GH, Saksela K, Schiller MR, Shin DG, Mayer BJ. High-throughput phosphotyrosine profiling using SH2 domains. Mol Cell 2007; 26:899-915. [PMID: 17588523 DOI: 10.1016/j.molcel.2007.05.031] [Citation(s) in RCA: 138] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2007] [Revised: 04/16/2007] [Accepted: 05/17/2007] [Indexed: 10/23/2022]
Abstract
Protein tyrosine phosphorylation controls many aspects of signaling in multicellular organisms. One of the major consequences of tyrosine phosphorylation is the creation of binding sites for proteins containing Src homology 2 (SH2) domains. To profile the global tyrosine phosphorylation state of the cell, we have developed proteomic binding assays encompassing nearly the full complement of human SH2 domains. Here we provide a global view of SH2 domain binding to cellular proteins based on large-scale far-western analyses. We also use reverse-phase protein arrays to generate comprehensive, quantitative SH2 binding profiles for phosphopeptides, recombinant proteins, and entire proteomes. As an example, we profiled the adhesion-dependent SH2 binding interactions in fibroblasts and identified specific focal adhesion complex proteins whose tyrosine phosphorylation and binding to SH2 domains are modulated by adhesion. These results demonstrate that high-throughput comprehensive SH2 profiling provides valuable mechanistic insights into tyrosine kinase signaling pathways.
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Affiliation(s)
- Kazuya Machida
- Raymond and Beverly Sackler Laboratory of Genetics and Molecular Medicine, Department of Genetics and Developmental Biology, University of Connecticut Health Center, Farmington, CT 06030, USA
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219
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Clarkson NG, Simmonds SJ, Puklavec MJ, Brown MH. Direct and indirect interactions of the cytoplasmic region of CD244 (2B4) in mice and humans with FYN kinase. J Biol Chem 2007; 282:25385-94. [PMID: 17599905 DOI: 10.1074/jbc.m704483200] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Engagement of the receptor CD244 (2B4) by its ligand CD48 has inhibitory and activating potential, and this differs depending on experimental systems in mouse and human. We show that, in both mouse and human upon engagement of its ligand CD48, CD244 can give a negative signal to natural killer cells, implying conservation of function between the two species. The signaling mechanisms used by CD244 in both human and mouse are conserved as shown by quantitative analyses of the direct molecular interactions of the SH2 domains of the adaptors SLAM-associated protein (SAP) and EAT-2 and of FYN kinase with CD244 together with the indirect interactions of the FYN SH2 domain with EAT-2. Functional experiments support the biochemical hierarchy of interactions and show that EAT-2 is not inhibitory per se. The data are consistent with a model in which the mechanism of signal transduction by CD244 is to regulate FYN kinase recruitment and/or activity and the outcome of CD48/CD244 interactions is determined by which other receptors are engaged.
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Affiliation(s)
- Nicholas G Clarkson
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, United Kingdom
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220
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Wu C, Ma MH, Brown KR, Geisler M, Li L, Tzeng E, Jia CYH, Jurisica I, Li SSC. Systematic identification of SH3 domain-mediated human protein–protein interactions by peptide array target screening. Proteomics 2007; 7:1775-85. [PMID: 17474147 DOI: 10.1002/pmic.200601006] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Systematic identification of direct protein-protein interactions is often hampered by difficulties in expressing and purifying the corresponding full-length proteins. By taking advantage of the modular nature of many regulatory proteins, we attempted to simplify protein-protein interactions to the corresponding domain-ligand recognition and employed peptide arrays to identify such binding events. A group of 12 Src homology (SH) 3 domains from eight human proteins (Swiss-Prot ID: SRC, PLCG1, P85A, NCK1, GRB2, FYN, CRK) were used to screen a peptide target array composed of 1536 potential ligands, which led to the identification of 921 binary interactions between these proteins and 284 targets. To assess the efficiency of the peptide array target screening (PATS) method in identifying authentic protein-protein interactions, we examined a set of interactions mediated by the PLCgamma1 SH3 domain by coimmunoprecipitation and/or affinity pull-downs using full-length proteins and achieved a 75% success rate. Furthermore, we characterized a novel interaction between PLCgamma1 and hematopoietic progenitor kinase 1 (HPK1) identified by PATS and demonstrated that the PLCgamma1 SH3 domain negatively regulated HPK1 kinase activity. Compared to protein interactions listed in the online predicted human interaction protein database (OPHID), the majority of interactions identified by PATS are novel, suggesting that, when extended to the large number of peptide interaction domains encoded by the human genome, PATS should aid in the mapping of the human interactome.
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Affiliation(s)
- Chenggang Wu
- Department of Biochemistry and the Siebens-Drake Research Institute, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
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221
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Jones N, Hardy WR, Friese MB, Jorgensen C, Smith MJ, Woody NM, Burden SJ, Pawson T. Analysis of a Shc family adaptor protein, ShcD/Shc4, that associates with muscle-specific kinase. Mol Cell Biol 2007; 27:4759-73. [PMID: 17452444 PMCID: PMC1951494 DOI: 10.1128/mcb.00184-07] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Shc family proteins serve as phosphotyrosine adaptor molecules in various receptor-mediated signaling pathways. In mammals, three distinct Shc genes have been described that encode proteins characterized by two phosphotyrosine-interaction modules, an amino-terminal phosphotyrosine binding (PTB) domain and a carboxy-terminal Src homology 2 domain. Here, we report the analysis of an uncharacterized fourth Shc family protein, ShcD/Shc4, that is expressed in adult brain and skeletal muscle. Consistent with this expression pattern, we find that ShcD can associate via its PTB domain with the phosphorylated muscle-specific kinase (MuSK) receptor tyrosine kinase and undergo tyrosine phosphorylation downstream of activated MuSK. Interestingly, additional sites of tyrosine phosphorylation, including a novel Grb2 binding site, are present on ShcD that are not found in other Shc family proteins. Activation of MuSK upon agrin binding at the neuromuscular junction (NMJ) induces clustering and tyrosine phosphorylation of acetylcholine receptors (AChRs) required for synaptic transmission. ShcD is coexpressed with MuSK in the postsynaptic region of the NMJ, and in cultured myotubes stimulated with agrin, expression of ShcD appears to be important for early tyrosine phosphorylation of the AChR. Thus, we have characterized a new member of the Shc family of docking proteins, which may mediate a specific aspect of signaling downstream of the MuSK receptor.
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Affiliation(s)
- Nina Jones
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, Ontario, Canada.
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222
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Peng Y, Schoenberg DR. c-Src activates endonuclease-mediated mRNA decay. Mol Cell 2007; 25:779-87. [PMID: 17349962 PMCID: PMC1861838 DOI: 10.1016/j.molcel.2007.01.026] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2006] [Revised: 01/08/2007] [Accepted: 01/19/2007] [Indexed: 02/03/2023]
Abstract
The mRNA endonuclease PMR1 initiates mRNA decay by forming a selective complex with its translating substrate mRNA. Previous work showed that the ability of PMR1 to target to polysomes and activate decay depends on the phosphorylation of a tyrosine residue at position 650. The current study shows that c-Src is responsible for activating this mRNA decay pathway. c-Src was recovered with immunoprecipitated PMR1, and it phosphorylates PMR1 in vitro and in vivo. The interaction with c-Src involves two domains of PMR1: Y650 and a series of proline-rich SH3 peptides in the N terminus. In cells with little c-Src, PMR1 targeting to polysomes is induced by constitutively active c-Src but not by inactive forms of the kinase. Similarly, only active c-Src induces PMR1-mediated mRNA decay. Finally, we show that EGF rapidly induces c-Src phosphorylation of PMR1, providing a direct link between tyrosine kinase-mediated signal transduction and mRNA decay.
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Affiliation(s)
| | - Daniel R. Schoenberg
- *Corresponding author: Daniel R. Schoenberg, Ph.D., Department of Molecular and Cellular Biochemistry The Ohio State University 333 Hamilton Hall 1645 Neil Ave., Columbus, OH 43210-1218 phone: (614) 688-3012 fax: (614) 292-4118
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223
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Ostrakhovitch EA, Li SSC. The role of SLAM family receptors in immune cell signaling. Biochem Cell Biol 2007; 84:832-43. [PMID: 17215871 DOI: 10.1139/o06-191] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The signaling lymphocyte-activating molecule (SLAM) family immunoreceptors are expressed in a wide array of immune cells, including both T and B lymphocytes. By virtue of their ability to transduce tyrosine phosphorylation signals through the so-called ITSM (immunoreceptor tyrosine-based switch motif) sequences, they play an important part in regulating both innate and adaptive immune responses. The critical role of the SLAM immunoreceptors in mediating normal immune reactions was highlighted in recent findings that SAP, a SLAM-associated protein, modulates the activities of various immune cells through interactions with different members of the SLAM family expressed in these cells. Importantly, mutations or deletions of the sap gene in humans result in the X-linked lymphoproliferative syndrome. In this review, we summarize current knowledge and survey the latest developments in signal transduction events triggered by the activation of SLAM family receptors in different cell types.
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Affiliation(s)
- Elena A Ostrakhovitch
- Department of Biochemistry, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON N6A 5C1, Canada
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224
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Fuller GL, Williams JA, Tomlinson MG, Eble JA, Hanna SL, Pöhlmann S, Suzuki-Inoue K, Ozaki Y, Watson SP, Pearce AC. The C-type lectin receptors CLEC-2 and Dectin-1, but not DC-SIGN, signal via a novel YXXL-dependent signaling cascade. J Biol Chem 2007; 282:12397-409. [PMID: 17339324 PMCID: PMC1997429 DOI: 10.1074/jbc.m609558200] [Citation(s) in RCA: 165] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The two lectin receptors, CLEC-2 and Dectin-1, have been shown to signal through a Syk-dependent pathway, despite the presence of only a single YXXL in their cytosolic tails. In this study, we show that stimulation of CLEC-2 in platelets and in two mutant cell lines is dependent on the YXXL motif and on proteins that participate in signaling by immunoreceptor tyrosine-based activation motif receptors, including Src, Syk, and Tec family kinases, and on phospholipase Cgamma. Strikingly, mutation of either Src homology (SH) 2 domain of Syk blocks signaling by CLEC-2 despite the fact that it has only a single YXXL motif. Furthermore, signaling by CLEC-2 is only partially dependent on the BLNK/SLP-76 family of adapter proteins in contrast to that of immunoreceptor tyrosine-based activation motif receptors. The C-type lectin receptor, Dectin-1, which contains a YXXL motif preceded by the same four amino acids as for CLEC-2 (DEDG), signals like CLEC-2 and also requires the two SH2 domains of Syk and is only partially dependent on the BLNK/SLP-76 family of adapters. In marked contrast, the C-type lectin receptor, DC-SIGN, which has a distinct series of amino acids preceding a single YXXL, signals independent of this motif. A mutational analysis of the DEDG sequence of CLEC-2 revealed that the glycine residue directly upstream of the YXXL tyrosine is important for CLEC-2 signaling. These results demonstrate that CLEC-2 and Dectin-1 signal through a single YXXL motif that requires the tandem SH2 domains of Syk but is only partially dependent on the SLP-76/BLNK family of adapters.
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Affiliation(s)
- Gemma L.J. Fuller
- Centre for Cardiovascular Sciences, Institute of Biomedical Research, University of Birmingham, Birmingham B15 2TT, UK
| | - Jennifer A.E. Williams
- Centre for Cardiovascular Sciences, Institute of Biomedical Research, University of Birmingham, Birmingham B15 2TT, UK
| | - Michael G. Tomlinson
- Centre for Cardiovascular Sciences, Institute of Biomedical Research, University of Birmingham, Birmingham B15 2TT, UK
| | - Johannes A. Eble
- Institute for Physiological Chemistry and Pathobiochemistry, Muenster University Hospital, Muenster, Germany
| | - Sheri L. Hanna
- Department of Microbiology, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
| | - Stefan Pöhlmann
- Institute for Clinical and Molecular Virology, University Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Katsue Suzuki-Inoue
- Department of Clinical and Laboratory Medicine, University of Yamanashi, 1110 Shimokato Tamaho Nakakoma, Yamanashi 409-3898, Japan
| | - Yukio Ozaki
- Department of Clinical and Laboratory Medicine, University of Yamanashi, 1110 Shimokato Tamaho Nakakoma, Yamanashi 409-3898, Japan
| | - Steve P. Watson
- Centre for Cardiovascular Sciences, Institute of Biomedical Research, University of Birmingham, Birmingham B15 2TT, UK
| | - Andrew C. Pearce
- Centre for Cardiovascular Sciences, Institute of Biomedical Research, University of Birmingham, Birmingham B15 2TT, UK
- Corresponding author: Dr Andrew C. Pearce, Centre for Cardiovascular Sciences, Institute of Biomedical Research, University of Birmingham, Birmingham B15 2TT, UK; Tel: +44 121 415 8679; Fax: +44 121 415 8817; E-mail:
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225
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Abstract
Signaling pathways in mammalian cells are assembled and regulated by a finely controlled network of protein-protein and protein-phospholipid interactions, mediated by dedicated signaling domains and their cognate binding motifs. The domain-based modular architecture of signaling proteins may have facilitated the evolution of complex biological systems, and can be exploited experimentally to generate synthetic signaling pathways and artificial mechanisms of autoregulation. Pathogenic proteins, such as those encoded by bacteria and viruses, frequently form ectopic signaling complexes to respecify cellular behavior. In a similar fashion, proteins expressed as a consequence of oncogenic fusions, mutations or amplifications can elicit ectopic protein-protein interactions that re-wire signaling pathways, in a fashion that promotes malignancy. Compounds that directly or indirectly reverse these aberrant interactions offer new possibilities for therapy in cancer.
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Affiliation(s)
- T Pawson
- Centre for Systems Biology, Samuel Lunenfeld Research Institute, Mt Sinai Hospital, 600 University Avenue, Toronto, Ontario, Canada.
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226
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Abstract
Identifying associated partners is critical to understanding the potential function and upstream and downstream pathways of the molecule being studied. The Src homology 2 (SH2) domain is a binding module for peptides containing a phosphotyrosine residue, which is a post-translational modification that is heavily involved in signal transduction. A paper in this issue shows how "reverse interactomics" can be exploited to identify binding partners of the SH2 domain of tensin.
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Affiliation(s)
- Su Hao Lo
- Lawrence Ellison Center for Tissue Regeneration and Repair, Department of Orthopaedic Surgery, Cancer Center, University of California-Davis, Sacramento, California 95817, USA.
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227
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Dierck K, Machida K, Voigt A, Thimm J, Horstmann M, Fiedler W, Mayer BJ, Nollau P. Quantitative multiplexed profiling of cellular signaling networks using phosphotyrosine-specific DNA-tagged SH2 domains. Nat Methods 2006; 3:737-44. [PMID: 16929320 DOI: 10.1038/nmeth917] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2006] [Accepted: 07/13/2006] [Indexed: 11/08/2022]
Abstract
Deciphering global signaling networks is of great importance for the detailed understanding of cellular signaling processes controlling many important biological functions. Among signaling processes, tyrosine phosphorylation has a central role. At present, adequate techniques for the global characterization of the tyrosine phosphoproteome are lacking, particularly for the analysis of small amounts of protein. By combining the power of PCR amplification with the unique properties of Src homology region 2 (SH2) domains to specifically recognize tyrosine-phosphorylated proteins, we developed a new proteomic approach, termed oligonucleotide-tagged multiplex assay (OTM). For OTM, multiple SH2 domains are labeled by domain-specific oligonucleotide tags, applied as probes to complex protein mixtures in a multiplex reaction and phosphotyrosine-specific interactions are quantified by PCR. Using OTM we reproducibly quantified differential states of tyrosine phosphorylation with high sensitivity and specificity in small amounts of whole cellular extracts as demonstrated for various tumor cell lines and human leukemia samples.
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Affiliation(s)
- Kevin Dierck
- Department of Clinical Chemistry, Center of Clinical Pathology, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany
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228
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Roux MM, Townley IK, Raisch M, Reade A, Bradham C, Humphreys G, Gunaratne HJ, Killian CE, Moy G, Su YH, Ettensohn CA, Wilt F, Vacquier VD, Burke RD, Wessel G, Foltz KR. A functional genomic and proteomic perspective of sea urchin calcium signaling and egg activation. Dev Biol 2006; 300:416-33. [PMID: 17054939 DOI: 10.1016/j.ydbio.2006.09.006] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2006] [Revised: 09/01/2006] [Accepted: 09/02/2006] [Indexed: 01/02/2023]
Abstract
The sea urchin egg has a rich history of contributions to our understanding of fundamental questions of egg activation at fertilization. Within seconds of sperm-egg interaction, calcium is released from the egg endoplasmic reticulum, launching the zygote into the mitotic cell cycle and the developmental program. The sequence of the Strongylocentrotus purpuratus genome offers unique opportunities to apply functional genomic and proteomic approaches to investigate the repertoire and regulation of Ca(2+) signaling and homeostasis modules present in the egg and zygote. The sea urchin "calcium toolkit" as predicted by the genome is described. Emphasis is on the Ca(2+) signaling modules operating during egg activation, but the Ca(2+) signaling repertoire has ramifications for later developmental events and adult physiology as well. Presented here are the mechanisms that control the initial release of Ca(2+) at fertilization and additional signaling components predicted by the genome and found to be expressed and operating in eggs at fertilization. The initial release of Ca(2+) serves to coordinate egg activation, which is largely a phenomenon of post-translational modifications, especially dynamic protein phosphorylation. Functional proteomics can now be used to identify the phosphoproteome in general and specific kinase targets in particular. This approach is described along with findings to date. Key outstanding questions regarding the activation of the developmental program are framed in the context of what has been learned from the genome and how this knowledge can be applied to functional studies.
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Affiliation(s)
- Michelle M Roux
- Department MCD Biology and Marine Science Institute, University of California, Santa Barbara, CA 93106-9610, USA
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