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Doggett K, Keating N, Dehkhoda F, Bidgood GM, Meza Guzman LG, Leong E, Kueh A, Nicola NA, Kershaw NJ, Babon JJ, Alexander WS, Nicholson SE. The SOCS1 KIR and SH2 domain are both required for suppression of cytokine signaling in vivo. Cytokine 2023; 165:156167. [PMID: 36934508 DOI: 10.1016/j.cyto.2023.156167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 02/22/2023] [Accepted: 02/24/2023] [Indexed: 03/19/2023]
Abstract
Suppressor Of Cytokine Signaling (SOCS) 1 is a critical negative regulator of cytokine signaling and required to protect against an excessive inflammatory response. Genetic deletion of Socs1 results in unrestrained cytokine signaling and neonatal lethality, characterised by an inflammatory immune infiltrate in multiple organs. Overexpression and structural studies have suggested that the SOCS1 kinase inhibitory region (KIR) and Src homology 2 (SH2) domain are important for interaction with and inhibition of the receptor-associated JAK1, JAK2 and TYK2 tyrosine kinases, which initiate downstream signaling. To investigate the role of the KIR and SH2 domain in SOCS1 function, we independently mutated key conserved residues in each domain and analysed the impact on cytokine signaling, and the in vivo impact on SOCS1 function. Mutation of the SOCS1-KIR or SH2 domain had no impact on the integrity of the SOCS box complex, however, mutation within the phosphotyrosine binding pocket of the SOCS1-SH2 domain specifically disrupted SOCS1 interaction with phosphorylated JAK1. In contrast, mutation of the KIR did not affect the interaction with JAK1, but did prevent SOCS1 inhibition of JAK1 autophosphorylation. In human and mouse cell lines, both mutants impacted the ability of SOCS1 to restrain cytokine signaling, and crucially, Socs1-R105A and Socs1-F59A mice displayed a neonatal lethality and excessive inflammatory phenotype similar to Socs1-null mice. This study defines a critical and non-redundant role for both the KIR and SH2 domain in endogenous SOCS1 function.
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Affiliation(s)
- Karen Doggett
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Department of Medical Biology, University of Melbourne, Parkville, Australia.
| | - Narelle Keating
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Department of Medical Biology, University of Melbourne, Parkville, Australia
| | - Farhad Dehkhoda
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Department of Medical Biology, University of Melbourne, Parkville, Australia
| | - Grace M Bidgood
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Department of Medical Biology, University of Melbourne, Parkville, Australia
| | - Lizeth G Meza Guzman
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Department of Medical Biology, University of Melbourne, Parkville, Australia
| | - Evelyn Leong
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
| | - Andrew Kueh
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Department of Medical Biology, University of Melbourne, Parkville, Australia
| | - Nicos A Nicola
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Department of Medical Biology, University of Melbourne, Parkville, Australia
| | - Nadia J Kershaw
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Department of Medical Biology, University of Melbourne, Parkville, Australia
| | - Jeffrey J Babon
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Department of Medical Biology, University of Melbourne, Parkville, Australia
| | - Warren S Alexander
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Department of Medical Biology, University of Melbourne, Parkville, Australia
| | - Sandra E Nicholson
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia; Department of Medical Biology, University of Melbourne, Parkville, Australia.
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SOCS2 regulation of growth hormone signaling requires a canonical interaction with phosphotyrosine. Biosci Rep 2022; 42:232115. [PMID: 36398696 DOI: 10.1042/bsr20221683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 10/21/2022] [Accepted: 10/26/2022] [Indexed: 11/19/2022] Open
Abstract
Suppressor of cytokine signaling (SOCS) 2 is the critical negative regulator of growth hormone (GH) and prolactin signaling. Mice lacking SOCS2 display gigantism with increased body weight and length, and an enhanced response to GH treatment. Here, we characterized mice carrying a germ-line R96C mutation within the SOCS2-SH2 domain, which disrupts the ability of SOCS2 to interact with tyrosine-phosphorylated targets. Socs2R96C/R96C mice displayed a similar increase in growth as previously observed in SOCS2 null (Socs2-/-) mice, with a proportional increase in body and organ weight, and bone length. Embryonic fibroblasts isolated from Socs2R96C/R96C and Socs2-/- mice also showed a comparable increase in phosphorylation of STAT5 following GH stimulation, indicating the critical role of phosphotyrosine binding in SOCS2 function.
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Nardella C, Malagrinò F, Pagano L, Rinaldo S, Gianni S, Toto A. Determining folding and binding properties of the C-terminal SH2 domain of SHP2. Protein Sci 2021; 30:2385-2395. [PMID: 34605082 PMCID: PMC8605372 DOI: 10.1002/pro.4201] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 09/29/2021] [Accepted: 10/01/2021] [Indexed: 01/17/2023]
Abstract
SH2 domains are a class of protein–protein interaction modules with the function to recognize and bind sequences characterized by the presence of a phosphorylated tyrosine. SHP2 is a protein phosphatase involved in the Ras‐ERK1/2 signaling pathway that possess two SH2 domains, namely, N‐SH2 and C‐SH2, that mediate the interaction of SHP2 with various partners and determine the regulation of its catalytic activity. One of the main interactors of the SH2 domains of SHP2 is Gab2, a scaffolding protein with critical role in determining cell differentiation. Despite their key biological role and the importance of a correct native fold to ensure it, the mechanism of binding of SH2 domains with their ligands and the determinants of their stability have been poorly characterized. In this article, we present a comprehensive kinetic study of the folding of the C‐SH2 domain and the binding mechanism with a peptide mimicking a region of Gab2. Our data, obtained at different pH and ionic strength conditions and supported by site‐directed mutagenesis, highlight the role of electrostatic interactions in the early events of recognition. Interestingly, our results suggest a key role of a highly conserved histidine residue among SH2 family in the interaction with negative charges carried by the phosphotyrosine of Gab2. Moreover, the analysis of the equilibrium and kinetic folding data of C‐SH2 describes a complex mechanism implying a change in rate‐limiting step at high denaturant concentrations. Our data are discussed under the light of previous works on N‐SH2 domain of SHP2 and other SH2 domains.
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Affiliation(s)
- Caterina Nardella
- Istituto Pasteur-Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche "A. Rossi Fanelli" and Istituto di Biologia e Patologia Molecolari del CNR, Sapienza Università di Roma, Rome, Italy
| | - Francesca Malagrinò
- Istituto Pasteur-Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche "A. Rossi Fanelli" and Istituto di Biologia e Patologia Molecolari del CNR, Sapienza Università di Roma, Rome, Italy
| | - Livia Pagano
- Istituto Pasteur-Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche "A. Rossi Fanelli" and Istituto di Biologia e Patologia Molecolari del CNR, Sapienza Università di Roma, Rome, Italy
| | - Serena Rinaldo
- Istituto Pasteur-Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche "A. Rossi Fanelli" and Istituto di Biologia e Patologia Molecolari del CNR, Sapienza Università di Roma, Rome, Italy
| | - Stefano Gianni
- Istituto Pasteur-Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche "A. Rossi Fanelli" and Istituto di Biologia e Patologia Molecolari del CNR, Sapienza Università di Roma, Rome, Italy
| | - Angelo Toto
- Istituto Pasteur-Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche "A. Rossi Fanelli" and Istituto di Biologia e Patologia Molecolari del CNR, Sapienza Università di Roma, Rome, Italy
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4
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Stec W, Vidal O, Zeidler MP. Drosophila SOCS36E negatively regulates JAK/STAT pathway signaling via two separable mechanisms. Mol Biol Cell 2013; 24:3000-9. [PMID: 23885117 PMCID: PMC3771960 DOI: 10.1091/mbc.e13-05-0275] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The low-complexity Drosophila genome includes previously uncharacterized SOCS36E, an ancestral SOCS4/5 homologue. It is shown that SOCS36E suppresses JAK/STAT signaling through two separate mechanisms: via receptor stability, mediated by the conserved SOCS-box domain, and via suppression of receptor phosphorylation that requires the N-terminal domain. Conserved from humans to Drosophila, the Janus kinase/signal transducer and activators of transcription (JAK/STAT) signaling cascade is essential for multiple developmental and homeostatic processes, with regulatory molecules controlling pathway activity also highly conserved. We characterize the Drosophila JAK/STAT pathway regulator SOCS36E and show that it functions via two independent mechanisms. First, we show that Drosophila Elongin B/C and Cullin-5 act via the SOCS-box of SOCS36E to reduce pathway activity specifically in response to ligand stimulation—a process that involves endocytic trafficking and lysosomal degradation of the Domeless (Dome) receptor. Second, SOCS36E also suppresses both stimulated and basal pathway activity via an Elongin/Cullin-independent mechanism that is mediated by the N-terminus of SOCS36E, which is required for the physical interaction of SOCS36E with Dome. Although some human SOCS proteins contain N-terminal kinase-inhibitory domains, we do not identify such a region in SOCS36E and propose a model wherein the N-terminal of SOCS36E blocks access to tyrosine residues in Dome. Our biochemical analysis of a SOCS-family regulator from a lower organism highlights the fundamental conserved roles played by regulatory mechanisms in signal transduction.
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Affiliation(s)
- Wojciech Stec
- MRC Centre for Development and Biomedical Genetics and Department of Biomedical Science, University of Sheffield, Sheffield S10 2TN, United Kingdom
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5
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Modified SH2 domain to phototrap and identify phosphotyrosine proteins from subcellular sites within cells. Proc Natl Acad Sci U S A 2012; 109:E2929-38. [PMID: 23027962 DOI: 10.1073/pnas.1207358109] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Spatial regulation of tyrosine phosphorylation is important for many aspects of cell biology. However, phosphotyrosine accounts for less than 1% of all phosphorylated substrates, and it is typically a very transient event in vivo. These factors complicate the identification of key tyrosine kinase substrates, especially in the context of their extraordinary spatial organization. Here, we describe an approach to identify tyrosine kinase substrates based on their subcellular distribution from within cells. This method uses an unnatural amino acid-modified Src homology 2 (SH2) domain that is expressed within cells and can covalently trap phosphotyrosine proteins on exposure to light. This SH2 domain-based photoprobe was targeted to cellular structures, such as the actin cytoskeleton, mitochondria, and cellular membranes, to capture tyrosine kinase substrates unique to each cellular region. We demonstrate that RhoA, one of the proteins associated with actin, can be phosphorylated on two tyrosine residues within the switch regions, suggesting that phosphorylation of these residues might modulate RhoA signaling to the actin cytoskeleton. We conclude that expression of SH2 domains within cellular compartments that are capable of covalent phototrapping can reveal the spatial organization of tyrosine kinase substrates that are likely to be important for the regulation of subcellular structures.
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Murillo-Maldonado JM, Zeineddine FB, Stock R, Thackeray J, Riesgo-Escovar JR. Insulin receptor-mediated signaling via phospholipase C-γ regulates growth and differentiation in Drosophila. PLoS One 2011; 6:e28067. [PMID: 22132213 PMCID: PMC3221684 DOI: 10.1371/journal.pone.0028067] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Accepted: 10/31/2011] [Indexed: 02/06/2023] Open
Abstract
Coordination between growth and patterning/differentiation is critical if appropriate final organ structure and size is to be achieved. Understanding how these two processes are regulated is therefore a fundamental and as yet incompletely answered question. Here we show through genetic analysis that the phospholipase C-γ (PLC-γ) encoded by small wing (sl) acts as such a link between growth and patterning/differentiation by modulating some MAPK outputs once activated by the insulin pathway; particularly, sl promotes growth and suppresses ectopic differentiation in the developing eye and wing, allowing cells to attain a normal size and differentiate properly. sl mutants have previously been shown to have a combination of both growth and patterning/differentiation phenotypes: small wings, ectopic wing veins, and extra R7 photoreceptor cells. We show here that PLC-γ activated by the insulin pathway participates broadly and positively during cell growth modulating EGF pathway activity, whereas in cell differentiation PLC-γ activated by the insulin receptor negatively regulates the EGF pathway. These roles require different SH2 domains of PLC-γ, and act via classic PLC-γ signaling and EGF ligand processing. By means of PLC-γ, the insulin receptor therefore modulates differentiation as well as growth. Overall, our results provide evidence that PLC-γ acts during development at a time when growth ends and differentiation begins, and is important for proper coordination of these two processes.
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Affiliation(s)
- Juan M. Murillo-Maldonado
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, Universidad Nacional Autónoma de México Campus Juriquilla, Querétaro, Querétaro, México
| | - Fouad Bou Zeineddine
- Biology Department, Clark University, Worcester, Maine, United States of America
| | - Rachel Stock
- Biology Department, Clark University, Worcester, Maine, United States of America
| | - Justin Thackeray
- Biology Department, Clark University, Worcester, Maine, United States of America
| | - Juan R. Riesgo-Escovar
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, Universidad Nacional Autónoma de México Campus Juriquilla, Querétaro, Querétaro, México
- * E-mail:
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7
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Kario E, Marmor MD, Adamsky K, Citri A, Amit I, Amariglio N, Rechavi G, Yarden Y. Suppressors of cytokine signaling 4 and 5 regulate epidermal growth factor receptor signaling. J Biol Chem 2004; 280:7038-48. [PMID: 15590694 DOI: 10.1074/jbc.m408575200] [Citation(s) in RCA: 118] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Suppressors of cytokine signaling (SOCS) are Src homology-2-containing proteins originally identified as negative regulators of cytokine signaling. Accumulating evidence indicates a role for SOCS proteins in the regulation of additional signaling pathways including receptor tyrosine kinases. Notably, SOCS36E, the Drosophila ortholog of mammalian SOCS5, was recently implicated as a negative regulator of the Drosophila ortholog of EGFR. In this study, we aimed at characterizing the role of SOCS5 in the negative regulation of EGFR. Here we show that the expression of SOCS5 and its closest homolog SOCS4 is elevated in cells following treatment with EGF, similar to several negative feedback regulators of EGFR whose expression is up-regulated upon receptor activation. The expression of SOCS5 led to a marked reduction in EGFR expression levels by promoting EGFR degradation. The reduction in EGFR levels and EGF-induced signaling in SOCS5-expressing cells requires both the Src homology-2 and SOCS box domains of SOCS5. Interestingly, EGFR is degraded by SOCS5 prior to EGF treatment in a ligand- and c-Cbl-independent manner. SOCS5 can associate with EGFR and can also bind the ElonginBC protein complex via its SOCS box, which may recruit an E3 ubiquitin ligase to promote EGFR degradation. Thus, we have characterized a novel function for SOCS5 in regulating EGFR and discuss its potential role in controlling EGFR homeostasis.
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Affiliation(s)
- Edith Kario
- Department of Biological Regulation, The Weizmann Institute of Science, Rehovot, 76100, Israel
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8
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Shapiro MJ, Powell P, Ndubuizu A, Nzerem C, Shapiro VS. The ALX Src homology 2 domain is both necessary and sufficient to inhibit T cell receptor/CD28-mediated up-regulation of RE/AP. J Biol Chem 2004; 279:40647-52. [PMID: 15284240 DOI: 10.1074/jbc.m404198200] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Activation of naive T cells occurs when two signals are received. The first signal is received through the T cell antigen receptor (TCR), and a second costimulatory signal is primarily provided by CD28. We have recently identified a novel adaptor molecule, ALX, which is expressed exclusively in hematopoietic cells. ALX contains several sites for potential protein-protein interaction, including an Src homology 2 (SH2) domain, four PXXP polyproline sequences, and two likely sites of tyrosine phosphorylation. Overexpression of ALX inhibits the transcriptional activation of the interleukin 2 promoter during T cell activation, specifically affecting CD28-mediated activation of the RE/AP element of the interleukin 2 promoter. To understand how ALX functions downstream of CD28, we generated a panel of site-directed mutants as well as truncations in which potential protein-binding sites were mutated or absent. We found that the ALX SH2 domain is both necessary and sufficient to mediate inhibition of RE/AP activation. Mutation of the SH2 domain did not affect ALX expression, relative localization in the cytoplasm and nucleus, phosphorylation, or a mobility shift in response to TCR signaling alone. However, an activation-induced mobility shift triggered by CD28 was reduced in the ALX SH2 domain mutant. In addition, the isolated ALX SH2 domain was found to associate with a phosphoprotein from Jurkat T cells on TCR/CD28 stimulation. Therefore, the ALX SH2 domain plays a critical role in ALX function downstream of CD28.
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Affiliation(s)
- Michael J Shapiro
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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Mahajan NP, Earp HS. An SH2 domain-dependent, phosphotyrosine-independent interaction between Vav1 and the Mer receptor tyrosine kinase: a mechanism for localizing guanine nucleotide-exchange factor action. J Biol Chem 2003; 278:42596-603. [PMID: 12920122 DOI: 10.1074/jbc.m305817200] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Mer belongs to the Mer/Axl/Tyro3 receptor tyrosine kinase family, which regulates immune homeostasis in part by triggering monocyte ingestion of apoptotic cells. Mutations in Mer can also cause retinitis pigmentosa, again due to defective phagocytosis of apoptotic material. Although, some functional aspects of Mer have been deciphered, how receptor activation lead to the physiological consequences is not understood. By using yeast two-hybrid assays, we identified the carboxyl-terminal region of the guanine nucleotide-exchange factor (GEF) Vav1 as a Mer-binding partner. Unlike similar (related) receptors, Mer interacted with Vav1 constitutively and independently of phosphotyrosine, yet the site of binding localized to the Vav1 SH2 domain. Mer activation resulted in tyrosine phosphorylation of Vav1 and release from Mer, whereas Vav1 was neither phosphorylated nor released from kinase-dead Mer. Mutation of the Vav1 SH2 domain phosphotyrosine coordinating Arg-696 did not alter Mer/Vav1 constitutive binding or Vav1 tyrosine phosphorylation but did retard Vav1 release from autophosphorylated Mer. Ligand-dependent activation of Mer in human monocytes led to Vav1 release and stimulated GDP replacement by GTP on RhoA family members. This unusual constitutive, SH2 domain-dependent, but phosphotyrosine-independent, interaction and its regulated local release and subsequent activation of Rac1, Cdc42, and RhoA may explain how Mer coordinates precise cytoskeletal changes governing the ingestion of apoptotic material by macrophages and pigmented retinal epithelial cells.
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Affiliation(s)
- Nupam P Mahajan
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 7599-7295, USA
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10
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Callus BA, Mathey-Prevot B. SOCS36E, a novel Drosophila SOCS protein, suppresses JAK/STAT and EGF-R signalling in the imaginal wing disc. Oncogene 2002; 21:4812-21. [PMID: 12101419 DOI: 10.1038/sj.onc.1205618] [Citation(s) in RCA: 121] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2002] [Revised: 04/19/2002] [Accepted: 04/26/2002] [Indexed: 11/09/2022]
Abstract
We have cloned a novel SOCS gene from Drosophila, socs36E, which is most homologous to the mammalian socs-5 gene. Socs36E is expressed zygotically, predominantly during embryogenesis, in a highly dynamic pattern. In vivo expression of SOCS36E in transgenic flies results in several adult phenotypes. Engrailed-GAL4 directed expression causes loss of the wing anterior cross vein, humeral outgrowths, absence of halteres and eye pigmentation defects. Expression of SOCS36E under apterous-GAL4 control resulted in outstretched wings. Full penetrance of these phenotypes required the presence of the SH2 and SOCS-box domains of SOCS36E. The observed phenotypes were consistent with defects in JAK/STAT or EGF-R signalling and were exacerbated in flies heterozygous for either the d-jak (hopscotch), d-stat (stat92E) or d-egf-r (der) genes. Conversely, inactivating one copy of the d-cbl gene, a negative regulator of the d-EGF-R, partially rescued the wing phenotypes. These genetic interactions imply that SOCS36E can suppress activities of the JAK/STAT and EGF-R signalling pathways in the wing disc and suggest that SOCS36E interacts with multiple pathways in vivo.
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Affiliation(s)
- Bernard A Callus
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, 44 Binney Street, Boston, Massachusetts, MA 02115, USA.
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Lock LS, Maroun CR, Naujokas MA, Park M. Distinct recruitment and function of Gab1 and Gab2 in Met receptor-mediated epithelial morphogenesis. Mol Biol Cell 2002; 13:2132-46. [PMID: 12058075 PMCID: PMC117630 DOI: 10.1091/mbc.02-02-0031] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The Gab family of docking proteins (Gab1 and Gab2) are phosphorylated in response to various cytokines and growth factors. Gab1 acts to diversify the signal downstream from the Met receptor tyrosine kinase through the recruitment of multiple signaling proteins, and is essential for epithelial morphogenesis. To determine whether Gab1 and Gab2 are functionally redundant, we have examined the role of Gab2 in epithelial cells. Both Gab1 and Gab2 are expressed in epithelial cells and localize to cell-cell junctions. However, whereas overexpression of Gab1 promotes a morphogenic response, the overexpression of Gab2 fails to induce this response. We show that Gab2 recruitment to the Met receptor is dependent on the Grb2 adapter protein. In contrast, Gab1 recruitment to Met is both Grb2 dependent and Grb2 independent. The latter requires a novel amino acid sequence present in the Met-binding domain of Gab1 but not Gab2. Mutation of these residues in Gab1 impairs both association with the Met receptor and the ability of Gab1 to promote a morphogenic response, whereas their insertion into Gab2 increases Gab2 association with Met, but does not confer on Gab2 the ability to promote epithelial morphogenesis. We propose that the Grb2-independent recruitment of Gab proteins to Met is necessary but not sufficient to promote epithelial morphogenesis.
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Affiliation(s)
- Lisa S Lock
- Department of Biochemistry, Molecular Oncology Group, McGill University Health Centre, Montreal, Quebec, Canada H3A 1A1
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12
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Sumegi J, Seemayer TA, Huang D, Davis JR, Morra M, Gross TG, Yin L, Romco G, Klein E, Terhorst C, Lanyi A. A spectrum of mutations in SH2D1A that causes X-linked lymphoproliferative disease and other Epstein-Barr virus-associated illnesses. Leuk Lymphoma 2002; 43:1189-201. [PMID: 12152986 DOI: 10.1080/10428190290026240] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
X-linked lymphoproliferative disease (Duncan's Disease) was first encountered by David T. Purtilo in 1969. The first communication describing the disease was published in 1975. In 1989 the disease locus was mapped to Xq25. Ten years later the gene (SH2D1A, SAP, DSHP), which is absent or mutated in XLP patients was identified. Since that the protein crystal structure of this small, SH2-domain containing protein has been solved, target molecules of the protein have been identified, physiological and pathological protein/protein interactions have been characterized, and the mouse model of the gene mutation has been developed. That said, a complete understanding of the function of the normal SH2D1A protein in immunoregulation and of the altered immune responses in XLP patients is not yet at hand. Therein lies the legacy of Purtilo's discovery for, as with other primary immunodeficiencies, these "experiments of nature" offer a window on the beauty of the immune system. In due course, the manner by which this gene orchestrates an elegant response (akin to a Mozart divertimento) to EBV infection shall be defined.
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Affiliation(s)
- Janos Sumegi
- Center of Human Genetics, University of Nebraska Medical Center, Omaha 68198-5454, USA.
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Mattsson PT, Lappalainen I, Bäckesjö CM, Brockmann E, Laurén S, Vihinen M, Smith CI. Six X-linked agammaglobulinemia-causing missense mutations in the Src homology 2 domain of Bruton's tyrosine kinase: phosphotyrosine-binding and circular dichroism analysis. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2000; 164:4170-7. [PMID: 10754312 DOI: 10.4049/jimmunol.164.8.4170] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Src homology 2 (SH2) domains recognize phosphotyrosine (pY)-containing sequences and thereby mediate their association to ligands. Bruton's tyrosine kinase (Btk) is a cytoplasmic protein tyrosine kinase, in which mutations cause a hereditary immunodeficiency disease, X-linked agammaglobulinemia (XLA). Mutations have been found in all Btk domains, including SH2. We have analyzed the structural and functional effects of six disease-related amino acid substitutions in the SH2 domain: G302E, R307G, Y334S, L358F, Y361C, and H362Q. Also, we present a novel Btk SH2 missense mutation, H362R, leading to classical XLA. Based on circular dichroism analysis, the conformation of five of the XLA mutants studied differs from the native Btk SH2 domain, while mutant R307G is structurally identical. The binding of XLA mutation-containing SH2 domains to pY-Sepharose was reduced, varying between 1 and 13% of that for the native SH2 domain. The solubility of all the mutated proteins was remarkably reduced. SH2 domain mutations were divided into three categories: 1) Functional mutations, which affect residues presumably participating directly in pY binding (R307G); 2) structural mutations that, via conformational change, not only impair pY binding, but severely derange the structure of the SH2 domain and possibly interfere with the overall conformation of the Btk molecule (G302E, Y334S, L358F, and H362Q); and 3) structural-functional mutations, which contain features from both categories above (Y361C).
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Affiliation(s)
- P T Mattsson
- Center for Biotechnology, Department of Biosciences, and Department of Immunology, Microbiology, Pathology and Infectious Diseases (IMPI), Karolinska Institute, Huddinge University Hospital, Huddinge, Sweden.
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14
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Lappalainen I, Giliani S, Franceschini R, Bonnefoy JY, Duckett C, Notarangelo LD, Vihinen M. Structural basis for SH2D1A mutations in X-linked lymphoproliferative disease. Biochem Biophys Res Commun 2000; 269:124-30. [PMID: 10694488 DOI: 10.1006/bbrc.2000.2146] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
X-linked lymphoproliferative disease (XLP) is a rare and severe immune deficiency, characterized by abnormal immune responses to the Epstein-Barr virus. Recently, the gene responsible for XLP, SH2D1A, has been identified and shown to code for a small cytoplasmic protein with an SH2 domain that interacts with SLAM and 2B4, two receptorial molecules involved in signal transduction in T and NK cells, respectively. A variety of SH2D1A gene mutations have been reported thus far in XLP males. Here we describe a single-strand conformation polymorphism assay for mutation analysis in XLP. Four novel patients with SH2D1A mutations are described. These mutants, and the others previously reported in the literature, have been included in a Registry (SH2D1Abase) that is fully accessible on the World Wide Web. A three-dimensional model of the SH2 domain of the SH2D1A protein has been developed, based on homology with other SH2 domains. The structural consequences of disease-causing SH2D1A mutations are discussed.
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Affiliation(s)
- I Lappalainen
- Institute of Medical Technology, University of Tampere, Tampere, FIN-33014, Finland
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15
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Kashige N, Carpino N, Kobayashi R. Tyrosine phosphorylation of p62dok by p210bcr-abl inhibits RasGAP activity. Proc Natl Acad Sci U S A 2000; 97:2093-8. [PMID: 10688886 PMCID: PMC15759 DOI: 10.1073/pnas.040547997] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The t(9;22) chromosomal translocation is found in almost all patients with chronic myelogenous leukemia. The resultant Bcr-Abl fusion gene expresses a chimeric fusion protein p210(bcr-abl) with increased tyrosine kinase activity. Hematopoietic progenitors isolated from chronic myelogenous leukemia patients in the chronic phase contain constitutively tyrosine-phosphorylated p62(dok) protein. p62(dok) associates with the Ras GTPase-activating protein (RasGAP), but only when p62(dok) is tyrosine phosphorylated. Here we have investigated the interaction between p62(dok) and RasGAP and the consequences of p62(dok) tyrosine phosphorylation on the activity of RasGAP. We have found that p62(dok) is directly tyrosine phosphorylated by p210(bcr-abl), and the sites of phosphorylation are located in the C-terminal half of the p62(dok) molecule. We have identified five tyrosine residues that are involved in in vitro RasGAP binding and have found that tyrosine-phosphorylated p62(dok) inhibits RasGAP activity. Our results suggest that p210(bcr-abl) might lead to the activation of the Ras signaling pathway by inhibiting a key down-regulator of Ras signaling.
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Affiliation(s)
- N Kashige
- Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY 11724, USA
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16
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Chattopadhyay A, Vecchi M, Ji QS, Mernaugh R, Carpenter G. The role of individual SH2 domains in mediating association of phospholipase C-gamma1 with the activated EGF receptor. J Biol Chem 1999; 274:26091-7. [PMID: 10473558 DOI: 10.1074/jbc.274.37.26091] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The two SH2 (Src homology domain 2) domains present in phospholipase C-gamma1 (PLC-gamma1) were assayed for their capacities to recognize the five autophosphorylation sites in the epidermal growth factor receptor. Plasmon resonance and immunological techniques were employed to measure interactions between SH2 fusion proteins and phosphotyrosine-containing peptides. The N-SH2 domain recognized peptides in the order of pY1173 > pY992 > pY1068 > pY1148 >> pY1086, while the C-SH2 domain recognized peptides in the order of pY992 > pY1068 > pY1148 >> pY1086 and pY1173. The major autophosphorylation site, pY1173, was recognized only by the N-SH2 domain. Contributions of the N-SH2 and C-SH2 domains to the association of the intact PLC-gamma1 molecule with the activated epidermal growth factor (EGF) receptor were assessed in vivo. Loss of function mutants of each SH2 domain were produced in a full-length epitope-tagged PLC-gamma1. After expression of the mutants, cells were treated with EGF and association of exogenous PLC-gamma1 with EGF receptors was measured. In this context the N-SH2 is the primary contributor to PLC-gamma1 association with the EGF receptor. The combined results suggest an association mechanism involving the N-SH2 domain and the pY1173 autophosphorylation site as a primary event and the C-SH2 domain and the pY992 autophosphorylation site as a secondary event.
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Affiliation(s)
- A Chattopadhyay
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146, USA
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17
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Lock P, Casagranda F, Dunn AR. Independent SH2-binding sites mediate interaction of Dok-related protein with RasGTPase-activating protein and Nck. J Biol Chem 1999; 274:22775-84. [PMID: 10428862 DOI: 10.1074/jbc.274.32.22775] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A murine embryonic cDNA library was screened for potential substrates of the Src family kinase, Lyn, using a phosphorylation-screening strategy. One cDNA that we identified encodes Dok-related protein (DokR), a protein with homology to p62(dok) (Dok), and members of the insulin receptor substrate-1 family of proteins. Analysis of murine tissue extracts with DokR-specific antisera revealed that DokR protein is expressed at highest levels in lymphoid tissues. Co-expression of a FLAG epitope-tagged form of DokR (FLAG-DokR) with Lyn in embryonic kidney 293T cells resulted in constitutive phosphorylation of FLAG-DokR on tyrosine residues and consequential physical association with RasGTPase-activating protein (GAP) and the Nck adaptor protein. Stimulation of BaF/3 hematopoietic cells co-expressing the epidermal growth factor (EGF) receptor tyrosine kinase and FLAG-DokR with EGF also induced phosphorylation of FLAG-DokR and promoted its association with GAP. Immunoprecipitation experiments using DokR-specific antibodies revealed an interaction between endogenous DokR and a 150-kDa protein that is tyrosine-phosphorylated in EGF-stimulated BaF/3 cells. The molecular basis of the interactions involving DokR with GAP and Nck was investigated using a novel glutathione S-transferase fusion protein binding assay and/or site-directed mutagenesis. Tandem SH2-binding sites containing Tyr-276 and Tyr-304 were shown to mediate binding of DokR to GAP, whereas Tyr-351 mediated the binding of DokR to Nck. These results suggest that DokR participates in numerous signaling pathways.
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Affiliation(s)
- P Lock
- Ludwig Institute for Cancer Research and the Cooperative Research Center for Cellular Growth Factors, P. O. Box 2008, Royal Melbourne Hospital, Parkville 3050, Australia.
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18
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Ji QS, Chattopadhyay A, Vecchi M, Carpenter G. Physiological requirement for both SH2 domains for phospholipase C-gamma1 function and interaction with platelet-derived growth factor receptors. Mol Cell Biol 1999; 19:4961-70. [PMID: 10373546 PMCID: PMC84312 DOI: 10.1128/mcb.19.7.4961] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Two approaches have been utilized to investigate the role of individual SH2 domains in growth factor activation of phospholipase C-gamma1 (PLC-gamma1). Surface plasmon resonance analysis indicates that the individual N-SH2 and C-SH2 domains are able to specifically recognize a phosphotyrosine-containing peptide corresponding to Tyr 1021 of the platelet-derived growth factor (PDGF) beta receptor. To assess SH2 function in the context of the full-length PLC-gamma1 molecule as well as within the intact cell, PLC-gamma1 SH2 domain mutants, disabled by site-directed mutagenesis of the N-SH2 and/or C-SH2 domain(s), were expressed in Plcg1(-/-) fibroblasts. Under equilibrium incubation conditions (4 degrees C, 40 min), the N-SH2 domain, but not the C-SH2 domain, was sufficient to mediate significant PLC-gamma1 association with the activated PDGF receptor and PLC-gamma1 tyrosine phosphorylation. When both SH2 domains in PLC-gamma1 were disabled, the double mutant did not associate with activated PDGF receptors and was not tyrosine phosphorylated. However, no single SH2 mutant was able to mediate growth factor activation of Ca2+ mobilization or inositol 1,4,5-trisphosphate (IP3) formation. Subsequent kinetic experiments demonstrated that each single SH2 domain mutant was significantly impaired in its capacity to mediate rapid association with activated PDGF receptors and become tyrosine phosphorylated. Hence, when assayed under physiological conditions necessary to achieve a rapid biological response (Ca2+ mobilization and IP3 formation), both SH2 domains of PLC-gamma1 are essential to growth factor responsiveness.
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Affiliation(s)
- Q S Ji
- Departments of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146, USA
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19
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Grgurevich S, Mikhael A, McVicar DW. The Csk homologous kinase, Chk, binds tyrosine phosphorylated paxillin in human blastic T cells. Biochem Biophys Res Commun 1999; 256:668-75. [PMID: 10080957 DOI: 10.1006/bbrc.1999.0398] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In determining the role of Chk in T cell signaling, we have focused on its protein-protein interactions. We detected a tyrosine phosphoprotein that coimmunoprecipitated with Chk from pervanadate stimulated human blastic T cells. Subsequent Western blot analysis identified this tyrosine phosphoprotein as paxillin. Paxillin, a cytoskeletal protein involved in focal adhesions, was first identified as a v-Src substrate in transformed fibroblasts. Interestingly, Chk specifically bound tyrosine phosphorylated paxillin. Consistent with our in vivo data, Chk and paxillin were observed to localize in similar cellular regions prior to and following stimulation. Using GST fusion proteins, we determined that the Chk SH2 domain, not the SH3 domain, bound tyrosine phosphorylated paxillin. Specifically, paxillin bound to the FLVRES motif of the Chk SH2 domain. Using Far Western analysis, we revealed that the Chk SH2 domain directly associates with tyrosine phosphorylated paxillin. Finally, p52(Chk) expression in Csk-deficient mouse embryo fibroblasts decreased total phosphotyrosine levels of paxillin, implying a physiological role for Chk. These studies provide important insight into the role of Chk in tyrosine mediated signaling, as well as T cell physiology.
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Affiliation(s)
- S Grgurevich
- Laboratory of Experimental Immunology, Division of Basic Sciences, National Cancer Institute, NCI-FCRDC, Frederick, Maryland, 21702-1201, USA
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20
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Narazaki M, Fujimoto M, Matsumoto T, Morita Y, Saito H, Kajita T, Yoshizaki K, Naka T, Kishimoto T. Three distinct domains of SSI-1/SOCS-1/JAB protein are required for its suppression of interleukin 6 signaling. Proc Natl Acad Sci U S A 1998; 95:13130-4. [PMID: 9789053 PMCID: PMC23734 DOI: 10.1073/pnas.95.22.13130] [Citation(s) in RCA: 203] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cytokine-inducible protein SSI-1 [signal transducers and activators of transcription (STAT)-induced STAT inhibitor 1, also referred to as SOCS-1 (suppressor of cytokine signaling 1) or JAB (Janus kinase-binding protein)] negatively regulates cytokine receptor signaling by inhibition of JAK kinases. The SSI family of proteins includes eight members that are structurally characterized by an SH2 domain and a C-terminal conserved region that we have called the SC-motif. In this study, we investigated the roles of these domains in the function of SSI-1. Results of reporter assays demonstrated that the pre-SH2 domain (24 aa in front of the SH2 domain) and the SH2 domain of SSI-1 were required for the suppression by SSI-1 of interleukin 6 signaling. Coexpression studies of COS7 cells revealed that these domains also were required for inhibition of three JAKs (JAK1, JAK2, and TYK2). Furthermore, deletion of the SH2 domain, but not the pre-SH2 domain, resulted in loss of association of SSI-1 with TYK2. Thus, SSI-1 associates with JAK family kinase via its SH2 domain, and the pre-SH2 domain is required for the function of SSI-1. Deletion of the SC-motif markedly reduced expression of SSI-1 protein in M1 cells, and this reduction was reversed by treatment with proteasome inhibitors, suggesting that this motif is required to protect the SSI-1 molecule from proteolytic degradation. Based on these findings, we concluded that three distinct domains of SSI-1 (the pre-SH2 domain, the SH2 domain, and the SC-motif) cooperate in the suppression of interleukin 6 signaling.
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Affiliation(s)
- M Narazaki
- Department of Medicine III, Osaka University Medical School, 2-2, Yamada-oka, Suita, Osaka 565-0871, Japan
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21
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Nelms K, Snow AJ, Noben-Trauth K. Dok1 encoding p62(dok) maps to mouse chromosome 6 and human chromosome 2 in a region of translocation in chronic lymphocytic leukemia. Genomics 1998; 53:243-5. [PMID: 9790776 DOI: 10.1006/geno.1998.5514] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
MESH Headings
- Animals
- Chromosome Mapping
- Chromosomes, Human, Pair 2
- Crosses, Genetic
- DNA-Binding Proteins
- Female
- Humans
- Leukemia, Lymphocytic, Chronic, B-Cell/genetics
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Inbred Strains
- Molecular Sequence Data
- Phosphoproteins/genetics
- Polymorphism, Genetic
- RNA-Binding Proteins
- Sequence Analysis, DNA
- Translocation, Genetic
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Affiliation(s)
- K Nelms
- Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland, 20892-1892, USA
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22
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Nelms K, Snow AL, Hu-Li J, Paul WE. FRIP, a hematopoietic cell-specific rasGAP-interacting protein phosphorylated in response to cytokine stimulation. Immunity 1998; 9:13-24. [PMID: 9697832 DOI: 10.1016/s1074-7613(00)80584-1] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The human IL-4 receptor contains a sequence (the 14R motif) centered on Y497 that, when phosphorylated, interacts with phosphotyrosine-binding (PTB) domain proteins. Here, we describe a PTB domain protein, FRIP, that is phosphorylated in response to cytokine stimulation. FRIP is related to the rasGAP-associated protein p62dok and is bound by the N-terminal SH2 domain of rasGAP. The frip gene maps to the hairless (hr) locus on mouse chromosome 14. hr/hr mice exhibit lymphadenopathy, and their lymph node T cells proliferate more vigorously to anti-CD3 with IL-4 or IL-2 stimulation than +/hr T cells. FRIP expression is significantly reduced in T cells from hr/hr mice. FRIP may negatively regulate proliferation by acting as an adapter molecule between rasGAP and receptor complexes.
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Affiliation(s)
- K Nelms
- Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
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23
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Sawka-Verhelle D, Filloux C, Tartare-Deckert S, Mothe I, Van Obberghen E. Identification of Stat 5B as a substrate of the insulin receptor. EUROPEAN JOURNAL OF BIOCHEMISTRY 1997; 250:411-7. [PMID: 9428692 DOI: 10.1111/j.1432-1033.1997.0411a.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We have screened a human placenta library using the yeast two-hybrid system to identify proteins that interact with the cytoplasmic domain of the insulin receptor. Doing so, we trapped a cDNA clone which encodes the Stat 5B region comprising amino acids 469 to 786. We show that interaction between Stat 5B and the receptor requires a functional insulin-receptor kinase, Tyr960 of insulin receptor is implicated in the interaction with Stat 5B, whereas asparagine and proline forming the NPEY960-motif are not, and Stat 5B mutated at Thr684, a potential phosphorylation site of mitogen-activated protein kinase, loses its ability to interact with the insulin receptor. Further, we found that insulin promotes rapid tyrosine phosphorylation of endogenous Stat 5B in 293 EBNA cells overexpressing insulin receptor and in NHIR cells. Taken together, our findings suggest that Stat 5B corresponds to a substrate for the insulin-receptor kinase, and this widens the repertoire of insulin-signaling pathways.
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Affiliation(s)
- D Sawka-Verhelle
- Institut National de la Santé et de la Recherche Médicale U145, Nice, France
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24
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Singer AU, Forman-Kay JD. pH titration studies of an SH2 domain-phosphopeptide complex: unusual histidine and phosphate pKa values. Protein Sci 1997; 6:1910-9. [PMID: 9300491 PMCID: PMC2143801 DOI: 10.1002/pro.5560060912] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Electrostatic interactions in a complex of the phospholipase C-gamma 1 C-terminal SH2 domain with a high-affinity binding phosphopeptide representing the sequence around Tyr 1021 of the beta platelet-derived growth factor receptor were studied by pKa determination of various titratable groups over the pH range of 5 to 8. A histidine residue that is highly conserved among SH2 domains (His beta D4) and the phosphotyrosine (pTyr) phosphate group show pKa values significantly lower than average for these residue types in proteins. The reduced pKa of these two groups is due to the proximity of the highly positively charged pTyr binding pocket. The unusual pKa of His beta D4 is also due to burial from solvent in a hydrogen-bonding network that appears necessary for the positioning of arginine residues involved in pTyr binding. Mutation of the analogous histidine in other SH2 domains has been shown to abrogate pTyr binding. In addition to these large shifts in pKa values, smaller effects were observed for the titratable groups of a glutamic acid and histidine near the C-terminus of the the second helix due to its helical dipole. Finally, exchange behavior of arginine guanidinium protons with solvent as a function of pH in this SH2 domain-phosphopeptide complex confirms previous descriptions of the roles of different arginines in the structure and function of this protein.
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Affiliation(s)
- A U Singer
- Department of Molecular and Medical Genetics, University of Toronto, Canada
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25
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Carpino N, Wisniewski D, Strife A, Marshak D, Kobayashi R, Stillman B, Clarkson B. p62(dok): a constitutively tyrosine-phosphorylated, GAP-associated protein in chronic myelogenous leukemia progenitor cells. Cell 1997; 88:197-204. [PMID: 9008160 DOI: 10.1016/s0092-8674(00)81840-1] [Citation(s) in RCA: 304] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Characteristic of chronic myelogenous leukemia (CML) is the presence of the chimeric p210(bcr-abl) protein possessing elevated protein tyrosine kinase activity relative to normal c-abl tyrosine kinase. Hematopoietic progenitors isolated from CML patients in the chronic phase contain a constitutively tyrosine-phosphorylated protein that migrates at 62 kDa by SDS-PAGE and associates with the p120 ras GTPase-activating protein (GAP). We have purified p62(dok) from a hematopoietic cell line expressing p210(bcr-abl). p62(dok) is a novel protein with features of a signaling molecule. Association of p62(dok) with GAP correlates with its tyrosine phosphorylation. p62(dok) is rapidly tyrosine-phosphorylated upon activation of the c-Kit receptor, implicating it as a component of a signal transduction pathway downstream of receptor tyrosine kinases.
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Affiliation(s)
- N Carpino
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
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26
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Fournier E, Rosnet O, Marchetto S, Turck CW, Rottapel R, Pelicci PG, Birnbaum D, Borg JP. Interaction with the phosphotyrosine binding domain/phosphotyrosine interacting domain of SHC is required for the transforming activity of the FLT4/VEGFR3 receptor tyrosine kinase. J Biol Chem 1996; 271:12956-63. [PMID: 8662748 DOI: 10.1074/jbc.271.22.12956] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The FLT4 gene encodes two isoforms of a tyrosine kinase receptor, which belongs to the family of receptors for vascular endothelial growth factor. As the result of an alternative processing of primary mRNA transcripts, the long isoform differs from the short isoform by an additional stretch of 65 amino acid residues located at the C terminus and containing three tyrosine residues, Tyr1333, Tyr1337, and Tyr1363. Only the long isoform is endowed with a transforming capacity in fibroblasts. We show that this activity is related to the capacity of the tyrosine 1337-containing sequence to interact with the phosphotyrosine binding domain of the SHC protein. This demonstrates that a functional property of this newly described domain includes relay of mitogenic signals. In addition, it shows that the same receptor can mediate different functions through the optional binding of the phosphotyrosine binding domain and that the alternative use of this domain is sufficient to direct the signal toward different pathways.
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Affiliation(s)
- E Fournier
- Laboratoire d'Oncologie Moléculaire, U119 INSERM, 27 Bd. Leï Roure, 13009 Marseille, France
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27
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O'Bryan JP, Martin CB, Songyang Z, Cantley LC, Der CJ. Binding specificity and mutational analysis of the phosphotyrosine binding domain of the brain-specific adaptor protein ShcC. J Biol Chem 1996; 271:11787-91. [PMID: 8662772 DOI: 10.1074/jbc.271.20.11787] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Shc proteins (hereafter referred to as ShcA) represent major substrates of tyrosine phosphorylation by a wide variety of growth factors and cytokines. We have recently described a novel ShcA-like protein, ShcC, which like ShcA contains an NH2-terminal phosphotyrosine binding domain (PTB), a central effector region (CH1) and a COOH-terminal Src homology 2 domain (SH2). Both the SH2 and PTB domains of ShcC bind a similar profile of proteins as the comparable regions of ShcA. In an effort to define the functional differences or similarities between ShcA and ShcC, we have further characterized the PTB domain of ShcC. Using a degenerate phosphopeptide library screen, we show that the PTB domain of ShcC preferentially binds the sequence His-hydrophobic-Asn/hydrophobic-Asn-Pro-Ser/Thr-Tyr(P). This sequence is similar to the binding site for the ShcA PTB domain, suggesting that these two proteins may have overlapping specificities. In addition, random mutagenesis of the ShcC PTB domain has identified several amino acids important for PTB function (Gly32, Glu63, Ala136, Gly139, and Asp140). Mutation of these amino acids dramatically reduces the affinity of the ShcC PTB domain for the activated epidermal growth factor receptor in vitro.
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Affiliation(s)
- J P O'Bryan
- Department of Pharmacology, University of North Carolina, Chapel Hill 27599, USA
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28
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Réty S, Fütterer K, Grucza RA, Munoz CM, Frazier WA, Waksman G. pH-Dependent self-association of the Src homology 2 (SH2) domain of the Src homologous and collagen-like (SHC) protein. Protein Sci 1996; 5:405-13. [PMID: 8868476 PMCID: PMC2143361 DOI: 10.1002/pro.5560050301] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The Src homologous and collagen-like (SHC) protein plays an essential role in signal transduction pathways in that it participates in the chain of events that leads to the activation of the protein Ras. The crystal structure of the SH2 domain of SHC has been determined using the method of multiple isomorphous replacement at a resolution of 2.5 A. The SH2 domain of SHC is similar in fold to other SH2 domains. The peptide-binding surfaces resemble that of the SH2 domain of Src in that a deep pocket is formed where the third amino acid C-terminal to the phosphotyrosine can insert. A novel feature of this structure is the observation of a disulfide bond and an extensive dimer interface between two symmetry-related molecules. Solution studies under reducing conditions using analytical centrifugation and PAGE suggest that the SH2 domain of SHC dimerizes in a pH-dependent manner where low pH conditions (approximately 4.5) are conducive to dimer formation. Dimerization of SHC may have important biological implications in that it may promote the assembly of large heteromultimeric signaling complexes.
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Affiliation(s)
- S Réty
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, Saint Louis, Missouri 63110, USA
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29
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Lock P, Fumagalli S, Polakis P, McCormick F, Courtneidge SA. The human p62 cDNA encodes Sam68 and not the RasGAP-associated p62 protein. Cell 1996; 84:23-4. [PMID: 8548822 DOI: 10.1016/s0092-8674(00)80989-7] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- P Lock
- Differentiation Programme, European Molecular Biology Laboratory, Heidelberg, Federal Republic of Germany
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30
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Teng KK, Lander H, Fajardo JE, Hanafusa H, Hempstead BL, Birge RB. v-Crk modulation of growth factor-induced PC12 cell differentiation involves the Src homology 2 domain of v-Crk and sustained activation of the Ras/mitogen-activated protein kinase pathway. J Biol Chem 1995; 270:20677-85. [PMID: 7657647 DOI: 10.1074/jbc.270.35.20677] [Citation(s) in RCA: 107] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Nerve growth factor (NGF) and epidermal growth factor (EGF) elicit contrasting actions on PC12 pheochromocytoma cells; NGF causes neuronal differentiation, and EGF induces proliferation. However, ectopic expression of the Src homology 2 (SH2) and SH3-containing oncogenic adaptor protein v-Crk in PC12 cells results in EGF-inducible neuronal differentiation (Hempstead, B. L., Birge, R. B., Fajardo, J. E., Glassman, R., Mahadeo, D., Kraemer, R., and Hanafusa, H. (1994) Mol. Cell. Biol. 14, 1964-1971). Here we show that v-Crk complexes with both the tyrosine-phosphorylated EGF receptor and the Ras guanine nucleotide exchange factor SOS in PC12 cells and is involved in an pathway analogous to that of Grb2. Expression of v-Crk results in an enhanced and sustained activation of Ras and mitogen-activated protein (MAP) kinase following EGF or NGF stimulation, implying that v-Crk can couple divergent tyrosine kinase pathways to Ras. To investigate the causal relationship between EGF receptor binding, MAP kinase activation, and neurite outgrowth, we stably expressed two v-Crk SH2 point mutants, v-Crk(R273N) and v-Crk(H294R) in PC12 cells. Mutations within the SH2 domain of v-Crk block binding of v-Crk to the tyrosine phosphorylated EGF receptor, compromise v-Crk's ability to cause EGF-dependent neurite outgrowth, and act in a dominant negative manner for NGF-induced neurite outgrowth. However, the kinetics of MAP kinase activation in EGF- or NGF-treated v-Crk-(R273N)PC12 cells was comparable with that in v-CrkPC12 cells. These data are consistent with a model in which v-Crk regulates the strength of a tyrosine kinase signal leading to prolonged activation of Ras and MAP kinase. However, the experiments with the SH2 mutants suggest that sustained activation, by itself, may not be sufficient to switch the fate of v-CrkPC12 cells from proliferation toward differentiation.
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Affiliation(s)
- K K Teng
- Department of Medicine, New York Hospital, Cornell University Medical College, New York 10021, USA
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31
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Abstract
An emerging theme in both the biology of signal transduction and the biochemistry of proteins has been the modular function of small protein domains. In some cases these can directly regulate catalytic activity. In others, they serve to interconnect important regulatory proteins. SH2 (src homology 2) domains represent some of the best studied models. Originally identified on the basis of homology in src and fps [1], SH2s are elements that ordinarily respond to tyrosine phosphorylation by binding the phosphorylated sequence. As such, they are key elements in tyrosine kinase regulation of cellular processes. Because SH2 interactions result from phosphorylation, such elements provide a regulatable circuitry along which signals can be transmitted in a timely manner. Because the regulation is based on a common mechanism, signal generators can target several different proteins coordinately. The PDGF receptor (PDGFr), for example, may interact with as many as ten different elements [2,3]. There are a number of excellent reviews on SH2 domains available [4-11]. This discussion will try to show how genetic, biochemical and biophysical results can be integrated in a satisfying way.
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Affiliation(s)
- B Schaffhausen
- Department of Biochemistry, Tufts University School of Medicine, Boston, Massachusetts 02111, USA
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Bryant SS, Briggs S, Smithgall TE, Martin GA, McCormick F, Chang JH, Parsons SJ, Jove R. Two SH2 domains of p120 Ras GTPase-activating protein bind synergistically to tyrosine phosphorylated p190 Rho GTPase-activating protein. J Biol Chem 1995; 270:17947-52. [PMID: 7629101 DOI: 10.1074/jbc.270.30.17947] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
p120 GTPase-activating protein (GAP) is a negative regulator of Ras that functions at a key relay point in signal transduction pathways that control cell proliferation. Among other proteins, p120 GAP associates with p190, a GAP for the Ras-related protein, Rho. To characterize the p120.p190 interaction further, we used bacterially expressed glutathione S-transferase fusion polypeptides to map the regions of p120 necessary for its interactions with p190. Our results show that both the N-terminal and the C-terminal SH2 domains of p120 are individually capable of binding p190 expressed in a baculovirus/insect cell system. Moreover, the two SH2 domains together on one polypeptide bind synergistically to p190, and this interaction is dependent on tyrosine phosphorylation of p190. In addition, mutation of the highly conserved Arg residues in the critical FLVR sequences of both SH2 domains of full-length p120 reduces binding to tyrosine-phosphorylated p190. The dependence on p190 phosphorylation for complex formation with p120 SH2 domains observed in vitro is consistent with analysis of the native p120.p190 complexes formed in vivo. These findings suggest that SH2-phosphotyrosine interaction is one mechanism by which the cell regulates p120.p190 association and thus may be a means for coordinating the Ras- and Rho-mediated signaling pathways.
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Affiliation(s)
- S S Bryant
- Cellular and Molecular Biology Program, University of Michigan Medical School, Ann Arbor 48109, USA
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33
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Abstract
Src homology 2 (SH2) domains bind specifically to tyrosine-phosphorylated proteins that participate in signaling by growth factors and oncogenes. A protein domain was identified that bound specifically to the tyrosine-phosphorylated form of its target protein but differs from known SH2 sequences. Phosphotyrosine-binding (PTB) domains were found in two proteins: SHC, a protein implicated in signaling through Ras; and SCK, encoded by a previously uncharacterized gene. The PTB domain of SHC specifically bound to a tyrosine-phosphorylated 145-kilodalton protein. PTB domains are an alternative to SH2 domains for specifically recruiting tyrosine-phosphorylated proteins into signaling complexes and are likely to take part in signaling by many growth factors.
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Affiliation(s)
- W M Kavanaugh
- Department of Medicine, University of California, San Francisco 94143
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34
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The beta D-sheet residues of the Lck-derived SH2 domain determine specificity of the interaction with tyrosine-phosphorylated ligands in Ramos B cells. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(20)30094-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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35
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Ogawa W, Hosomi Y, Shii K, Roth RA. Evidence for two distinct 60-kilodalton substrates of the SRC tyrosine kinase. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(18)43923-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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36
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Marengere LE, Songyang Z, Gish GD, Schaller MD, Parsons JT, Stern MJ, Cantley LC, Pawson T. SH2 domain specificity and activity modified by a single residue. Nature 1994; 369:502-5. [PMID: 7515480 DOI: 10.1038/369502a0] [Citation(s) in RCA: 153] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Many intracellular targets of protein-tyrosine kinases possess Src homology 2 (SH2) domains that directly recognize phosphotyrosine-containing sites on autophosphorylated growth factor receptors and cytoplasmic proteins, and thereby mediate the activation of biochemical signalling pathways. SH2 domains possess relatively well conserved residues that form the phosphotyrosine-binding pocket, and more variable residues that are implicated in determining binding specificity by recognition of the three amino acids carboxy-terminal to phosphotyrosine (the +1 to +3 positions). One such residue, occupying the EF1 position of the +3-binding pocket, is a Thr in the SH2 domain of the Src tyrosine kinase, but is predicted to be a Trp in the SH2 domain of the Sem-5/drk/Grb2 adaptor protein. Here we report that changing this residue in the Src SH2 domain from Thr to Trp switches its selectivity to resemble that of the Sem-5/drk/Grb2 SH2 domain. Furthermore, this mutant Src SH2 domain effectively substitutes for the SH2 domain of the Sem-5 protein in activation of the Ras pathway in vivo. These results identify a residue that can modify SH2 selectivity, and indicate that the biological activity of an SH2 domain correlates with its binding specificity.
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Affiliation(s)
- L E Marengere
- Division of Molecular and Developmental Biology, Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada
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Lee CH, Kominos D, Jacques S, Margolis B, Schlessinger J, Shoelson SE, Kuriyan J. Crystal structures of peptide complexes of the amino-terminal SH2 domain of the Syp tyrosine phosphatase. Structure 1994; 2:423-38. [PMID: 7521735 DOI: 10.1016/s0969-2126(00)00044-7] [Citation(s) in RCA: 160] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
BACKGROUND Src homology 2 (SH2) domains bind to phosphotyrosine residues in a sequence-specific manner, and thereby couple tyrosine phosphorylation to changes in the localization or catalytic activity of signal transducing molecules. Current understanding of SH2 specificity is based on the structures of SH2-peptide complexes of the closely-related Src and Lck tyrosine kinases. The tyrosine phosphatase Syp contains two SH2 domains that are relatively divergent from those of the tyrosine kinases, with distinct target specificities, and is thus well suited for structural studies aimed at extending our understanding of SH2 specificity. RESULTS Crystal structures of the amino-terminal SH2 domain of Syp in separate complexes with two high-affinity peptides, in complex with a non-specific peptide and in the uncomplexed form have been determined at between 2 A and 3 A resolution. The structure of the SH2 domain and the mode of high-affinity peptide binding is essentially similar to that seen in the Src and Lck structures. However, the binding interface is more extensive in Syp. CONCLUSIONS Most SH2 targets have hydrophobic residues at the third position following the phosphotyrosine, and the Syp structure confirms that the peptide is anchored to the SH2 surface by this residue and by the phosphotyrosine. In addition, the Syp structure has revealed that sequence specificity can extend across the five residues following the phosphotyrosine, and has shown how the SH2 domain's surface topography can be altered with resulting changes in specificity, while conserving the structure of the central core of the domain.
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Affiliation(s)
- C H Lee
- Laboratory of Molecular Biophysics, Rockefeller University, New York, NY 10021
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38
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Sung C, Sánchez-Margalet V, Goldfine I. Role of p85 subunit of phosphatidylinositol-3-kinase as an adaptor molecule linking the insulin receptor, p62, and GTPase-activating protein. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(18)99903-5] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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39
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Panaretto BA. Aspects of growth factor signal transduction in the cell cytoplasm. J Cell Sci 1994; 107 ( Pt 4):747-52. [PMID: 8056834 DOI: 10.1242/jcs.107.4.747] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- B A Panaretto
- CSIRO, Division of Animal Production, Blacktown, NSW, Australia
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40
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Affiliation(s)
- T Pawson
- Division of Molecular and Developmental Biology, Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada
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41
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Park S, Jove R. Tyrosine phosphorylation of Ras GTPase-activating protein stabilizes its association with p62 at membranes of v-Src transformed cells. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(19)74450-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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42
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Soler C, Beguinot L, Sorkin A, Carpenter G. Tyrosine phosphorylation of ras GTPase-activating protein does not require association with the epidermal growth factor receptor. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(20)80641-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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