FRINK Linked Data Fragments server

Matches in SemOpenAlex for { <https://semopenalex.org/work/W2016207825> ?p ?o ?g. }

• W2016207825 endingPage "17902" @default.
• W2016207825 startingPage "17899" @default.
• W2016207825 abstract "Tyrosine kinases of the Src family are regulated via their Src homology 2 (SH2) and SH3 domains. The Nef protein of human immunodeficiency virus-1 (HIV-1) has previously been shown to bind with high affinity and specificity in vitro to the SH3 domain of Hck, a Src family member expressed primarily in myeloid cells. However, the effect of Nef on Hck activity in living cells is unknown. Here we show that Rat-2 fibroblasts co-expressing Hck and Nef rapidly developed transformed foci, whereas control cells expressing either protein alone did not. Nef formed a stable complex with Hck and stimulated its tyrosine kinase activity in vivo. Mutagenesis of the Nef proline-rich motif essential for SH3 binding completely blocked complex formation, kinase activation, and transformation, indicating that the Nef SH3-binding function is required for its effects on Hck. These results provide direct evidence that SH3 engagement is sufficient to activate a Src family kinasein vivo and suggest that Hck may be activated by Nef in HIV-infected macrophages. Tyrosine kinases of the Src family are regulated via their Src homology 2 (SH2) and SH3 domains. The Nef protein of human immunodeficiency virus-1 (HIV-1) has previously been shown to bind with high affinity and specificity in vitro to the SH3 domain of Hck, a Src family member expressed primarily in myeloid cells. However, the effect of Nef on Hck activity in living cells is unknown. Here we show that Rat-2 fibroblasts co-expressing Hck and Nef rapidly developed transformed foci, whereas control cells expressing either protein alone did not. Nef formed a stable complex with Hck and stimulated its tyrosine kinase activity in vivo. Mutagenesis of the Nef proline-rich motif essential for SH3 binding completely blocked complex formation, kinase activation, and transformation, indicating that the Nef SH3-binding function is required for its effects on Hck. These results provide direct evidence that SH3 engagement is sufficient to activate a Src family kinasein vivo and suggest that Hck may be activated by Nef in HIV-infected macrophages. The Src family of non-receptor tyrosine kinases consists of nine members (Src, Lck, Hck, Fyn, Fgr, Yes, Blk, Lyn, and Yrk) that share common structural features and regulation (reviewed in Ref. 1Brown M.T. Cooper J.A. Biochim. Biophys. Acta. 1996; 1287: 121-149Crossref PubMed Scopus (1080) Google Scholar). The N-terminal region of each kinase contains a signal for myristoylation and in some cases palmitoylation; both lipid modifications are involved in membrane targeting. Adjacent to the N-terminal region is a Src homology (SH3) 1The abbreviations used are: SH, Src homology; HIV, human immunodeficiency virus; SIV, simian immunodeficiency virus; WT, wild-type; PAGE, polyacrylamide gel electrophoresis. 1The abbreviations used are: SH, Src homology; HIV, human immunodeficiency virus; SIV, simian immunodeficiency virus; WT, wild-type; PAGE, polyacrylamide gel electrophoresis. domain consisting of approximately 60 amino acids. SH3 domains bind to target proteins via specific proline-rich sequences that adopt a polyproline type II helical conformation (2Kuriyan J. Cowburn D. Curr. Opin. Struct. Biol. 1993; 3: 828-837Crossref Scopus (107) Google Scholar, 3Cohen G.B. Ren R. Baltimore D. Cell. 1995; 80: 237-248Abstract Full Text PDF PubMed Scopus (925) Google Scholar, 4Pawson T. Nature. 1995; 373: 573-580Crossref PubMed Scopus (2222) Google Scholar). Protein-protein interactions mediated by Src kinase SH3 domains contribute to substrate recruitment, subcellular localization, and negative regulation of kinase activity (see below). C-terminal to the SH3 domain is the SH2 domain. Comprised of approximately 100 amino acids, SH2 domains bind tightly to specific tyrosine-phosphorylated sequences. As for SH3 domains, SH2 domains also contribute to negative regulation of kinase activity, subcellular localization, and interaction with signaling partners. The SH2 domain is followed by the kinase domain and a C-terminal tail with a highly conserved tyrosine residue essential to kinase regulation. SH2 and SH3 domains cooperate in the negative regulation of Src family kinase activity (1Brown M.T. Cooper J.A. Biochim. Biophys. Acta. 1996; 1287: 121-149Crossref PubMed Scopus (1080) Google Scholar). Phosphorylation of the conserved tyrosine residue in the C-terminal tail (Tyr-527 in Src) by the regulatory kinase Csk (5Nada S. Okada M. MacAuley A. Cooper J.A. Nakagawa H. Nature. 1991; 351: 69-72Crossref PubMed Scopus (510) Google Scholar) is postulated to promote intramolecular binding to the SH2 domain, contributing to a closed and inactive kinase conformation. A large body of genetic and biochemical evidence supports this model. For example, conversion of the conserved Tyr residue in the tail to Phe or mutation of the SH2 domain results in a constitutively active kinase capable of producing a transformed phenotype in rodent fibroblasts (6Hirai H. Varmus H. Mol. Cell. Biol. 1990; 10: 1307-1318Crossref PubMed Google Scholar, 7Hunter T. Cell. 1987; 49: 1-4Abstract Full Text PDF PubMed Scopus (198) Google Scholar). Such mutations presumably interfere with intramolecular SH2-tail interaction. Many studies have shown an essential role for the SH3 domain in the negative regulation of Src family kinase activity as well. Mutants of Src lacking a functional SH3 domain are also resistant to Csk-mediated negative regulation and are often transforming (8Superti-Furga G. Fumagalli S. Koegl M. Courtneidge S.A. Draetta G. EMBO J. 1993; 12: 2625-2634Crossref PubMed Scopus (220) Google Scholar, 9Murphy S.M. Bergman M. Morgan D.O. Mol. Cell. Biol. 1993; 13: 5290-5300Crossref PubMed Scopus (116) Google Scholar, 10Okada M. Howell B.W. Broome M.A. Cooper J.A. J. Biol. Chem. 1993; 268: 18070-18075Abstract Full Text PDF PubMed Google Scholar, 11Seidel-Dugan C. Meyer B.E. Thomas S.M. Brugge J.S. Mol. Cell. Biol. 1992; 12: 1835-1845Crossref PubMed Scopus (150) Google Scholar, 12Erpel T. Superti-Furga G. Courtneidge S.A. EMBO J. 1995; 14: 963-975Crossref PubMed Scopus (142) Google Scholar). These findings suggest that interaction of Src kinase SH2 or SH3 domains with target proteins may destabilize the closed conformationin vivo, leading to kinase activation. Such a mechanism may be responsible for the activation of Src kinases following recruitment via their SH2 domains to autophosphorylated growth factor receptors (13Courtneidge S.A. Dhand R. Pilat D. Twamley G.M. Waterfield M.D. Roussel M.F. EMBO J. 1993; 12: 943-950Crossref PubMed Scopus (204) Google Scholar, 14Mori S. Rönnstrand L. Yokote K. Engström Å. Courtneidge S.A. Claesson-Welsh L. Heldin C.-H. EMBO J. 1993; 12: 2257-2264Crossref PubMed Scopus (295) Google Scholar). Whether or not SH3-mediated interaction of Src kinases with target proteins is sufficient to activate the kinase domain in vivo is less clear. In this study, we investigated the effects of SH3 domain engagement on the activity of a Src-related kinase in living cells. Our model system consisted of Hck, a Src family member expressed primarily in macrophages and neutrophils (15Ziegler S.F. Marth J.D. Lewis D.B. Perlmutter R.M. Mol. Cell. Biol. 1987; 7: 2276-2285Crossref PubMed Scopus (178) Google Scholar, 16Quintrell N. Lebo R. Varmus H. Bishop J.M. Pettenati M.J. Le Beau M.M. Diaz M.O. Rowley J.D. Mol. Cell. Biol. 1987; 7: 2267-2275Crossref PubMed Scopus (202) Google Scholar, 17Holtzman D.A. Cook W.D. Dunn A.R. Proc. Natl. Acad. Sci. U. S. A. 1987; 84: 8325-8329Crossref PubMed Scopus (57) Google Scholar), and the Nef protein of the human immunodeficiency virus-1 (HIV-1). Nef is essential for the high titer replication of HIV and SIV and for the induction of AIDS-like disease in monkeys (reviewed in Refs. 18Stevenson M. Nat. Struct. Biol. 1996; 3: 303-306Crossref PubMed Scopus (10) Google Scholar and 19Trono D. Cell. 1995; 82: 189-192Abstract Full Text PDF PubMed Scopus (241) Google Scholar). Previous reports have shown that Nef specifically binds to the SH3 domain of Hck in vitro with the highest affinity known for an SH3-mediated interaction (20Saksela K. Cheng G. Baltimore D. EMBO J. 1995; 14: 484-491Crossref PubMed Scopus (504) Google Scholar, 21Lee C.H. Leung B. Lemmon M.A. Zheng J. Cowburn D. Kuriyan J. Saksela K. EMBO J. 1995; 14: 5006-5015Crossref PubMed Scopus (236) Google Scholar). These findings suggested that Nef may represent an excellent probe of Hck SH3 function in vivo. As shown below, co-expression of Nef with Hck in Rat-2 fibroblasts resulted in the appearance of a transformed phenotype that correlated with the SH3-dependent activation of Hck in vivo. These results suggest that interaction of Src family kinases with SH3 ligands may be sufficient to activate Src family kinases in vivo. The Nef gene from HIV isolate SF2 was amplified by polymerase chain reaction and subcloned into the retroviral vector pSRαMSVtkneo (22Muller A.J. Young J.C. Pendergast A.M. Pondel M. Landau R.N. Littman D.R. Witte O.N. Mol. Cell. Biol. 1991; 11: 1785-1792Crossref PubMed Scopus (354) Google Scholar). Wild-type (WT), kinase-defective (K269E), and activated (Y501F) forms of human p59 Hck were also subcloned into the same vector. The mutant forms of Hck were generated by a standard polymerase chain reaction-based strategy as described elsewhere (23Briggs S.D. Bryant S.S. Jove R. Sanderson S.D. Smithgall T.E. J. Biol. Chem. 1995; 270: 14718-14724Abstract Full Text Full Text PDF PubMed Scopus (60) Google Scholar). The resulting constructs were used to generate high titer retroviral stocks by co-transfection of 293T cells (24Pear W.S. Nolan G.P. Scott M.L. Baltimore D. Proc. Natl. Acad. Sci. U. S. A. 1993; 90: 8392-8396Crossref PubMed Scopus (2291) Google Scholar) with an ecotropic packaging vector. Control retroviruses were prepared using the parent vector. For each infection, 2.5 × 104 Rat-2 cells were plated per well in 6-well tissue culture plates and incubated with viral stocks in a final volume of 6 ml. To enhance the efficiency of infection, cultures were centrifuged at 1,000 × g for 4 h at 18 °C (25Bahnson A.B. Dunigan J.T. Baysal B.E. Mohney T. Atchison R.W. Nimgaonkar M.T. Ball E.D. Barranger J.A. J. Virol. Methods. 1995; 54: 131-143Crossref PubMed Scopus (182) Google Scholar) in the presence of 4 μg/ml Polybrene. Following infection, the virus was replaced with fresh medium, and G418 (400 μg/ml) was added 48 h later. Transformed foci were counted after 2 weeks. To detect Hck-Nef protein complexes, cells were sonicated briefly in 1.0 ml of detergent buffer (50 mm Tris-HCl, pH 7.4, 50 mm NaCl, 1 mm EDTA, 10 mmMgCl2, and 1% Triton X-100). Clarified supernatants were incubated with 2 μg of anti-Hck antibody (Santa Cruz Biotechnology) and 15 μl of protein G-Sepharose (50% slurry; Pharmacia Biotech Inc.) for 2.5 h at 4 °C. Immunoprecipitates were washed three times with 1.0 ml of RIPA buffer (50 mm Tris-HCl, 150 mm NaCl, 1% Triton X-100, 0.1% SDS, 1 mmEDTA, and 1% sodium deoxycholate). Immunoprecipitates were heated in SDS-PAGE sample buffer, resolved by SDS-PAGE, transferred to polyvinylidene difluoride membranes, and probed for associated Nef by immunoblotting with anti-Nef monoclonal antibodies (kindly supplied by Dr. James A. Hoxie, University of Pennsylvania). For analysis of protein-tyrosine phosphorylation or protein expression, whole cell lysates were prepared by heating cells directly in SDS-PAGE sample buffer. Lysate proteins were separated by SDS-PAGE, transferred to polyvinylidene difluoride, and immunoblotted with anti-Hck monoclonal antibodies (Transduction Laboratories), anti-phosphotyrosine antibodies (PY20; Transduction Laboratories), or anti-Nef monoclonal antibodies. Immunoreactive bands were visualized colorimetrically using alkaline phosphatase-conjugated secondary antibodies and nitro blue tetrazolium/5-bromo-4-chloro-3-indolyl phosphate as substrate. To determine whether interaction with Nef influences Hck activity under physiological conditions, Rat-2 fibroblasts were co-infected with recombinant retroviruses containing wild-type, activated, or kinase-defective forms of Hck and either a Nef retrovirus or a control virus containing only the bacterial neo resistance marker. After 2 weeks, transformed foci were readily observed in cells expressing wild-type Hck and Nef (Fig. 1 and TableI). In contrast, no transformed foci were observed in cells expressing wild-type Hck or Nef alone. The foci resulting from the co-expression of Nef and Hck were morphologically indistinguishable from those produced by an activated allele of Hck in which the negative regulatory tyrosine residue in the C-terminal tail was mutated to phenylalanine (Hck-YF mutant) (Fig. 1). Fewer foci were observed with the co-infected cells relative to the Hck-YF cells (Table I), probably because transformation is dependent upon successful co-infection and expression of both Hck and Nef within the same cell. No transformed foci were observed following co-expression of Nef with a kinase-defective Hck mutant (Hck-KE; Ref. 23Briggs S.D. Bryant S.S. Jove R. Sanderson S.D. Smithgall T.E. J. Biol. Chem. 1995; 270: 14718-14724Abstract Full Text Full Text PDF PubMed Scopus (60) Google Scholar), demonstrating the requirement for Hck tyrosine kinase activity in the initiation of transformation by Nef. We also observed that the transforming activity of Hck-YF was not detectably affected by co-expression with Nef (TableI), despite the ability of these two proteins to associate in vivo (see below).Table ICo-expression of Nef and Hck results in transformation of Rat-2 fibroblastsRetroviral combinationNumber of foci/platenHck-WT + vector06Hck-KE + vector03Hck YF + vector>503Nef + vector03Hck-WT + Nef17 ± 3.7 (S.E.)6Hck-KE + Nef03Hck YF + Nef>503Hck WT + Nef-PA03Vector alone03Rat-2 cells were plated in six-well tissue culture plates and infected with recombinant retroviruses in the combinations shown. Two days after infection, cells were trypsinized and replated in duplicate 60-mm tissue culture dishes in the presence of G418. Transformed foci were counted after 14 days. Open table in a new tab Rat-2 cells were plated in six-well tissue culture plates and infected with recombinant retroviruses in the combinations shown. Two days after infection, cells were trypsinized and replated in duplicate 60-mm tissue culture dishes in the presence of G418. Transformed foci were counted after 14 days. To verify that the Nef and Hck proteins were expressed in the transformants as well as the non-transformed control cells, immunoblots were performed on whole cell lysates. As shown in Fig.2, Hck and Nef proteins were readily detected in cells infected with the corresponding retroviruses. Taken together, these results demonstrate that Nef and Hck cooperate to induce fibroblast transformation in a Hck kinase-dependent manner. The biological data described above support a model in which Nef binds to the Hck SH3 domain in vivo, leading to activation of the kinase domain and cellular transformation. To test this model, we assessed Hck autophosphorylation and tyrosine phosphorylation of endogenous proteins in lysates from control and transformed cell lines. Cells were lysed directly in SDS-PAGE sample buffer, and tyrosine phosphoproteins were visualized by immunoblotting with anti-phosphotyrosine antibodies. As shown in Fig. 3, transformed cells expressing both Hck and Nef showed several prominent tyrosine-phosphorylated proteins. These include an ∼60-kDa phosphoprotein with electrophoretic mobility identical to Hck as well as a second strong band of ∼40 kDa. A nearly identical pattern of protein-tyrosine phosphorylation was observed in cells transformed with the activated form of Hck (Hck-YF), including the 40-kDa transformation-related protein. Although we have not identified the endogenous 40-kDa transformation-associated tyrosyl phosphoprotein, immunoblotting experiments indicate that it is not the Src substrates c-Crk, annexin I, or annexin II which are in this molecular mass range (data not shown). None of the untransformed control cell lines showed evidence of protein-tyrosine phosphorylation, including cells expressing Nef alone, Hck-WT alone, or cells co-expressing Nef and the kinase-defective Hck mutant. These results show that co-expression with Nef leads to constitutive activation of the Hck tyrosine kinase in living cells. We next investigated whether Nef directly interacts with Hck in vivo. Hck was immunoprecipitated from transformed cells and probed for associated Nef by immunoblotting. As shown in Fig.4, Hck-Nef complexes were readily immunoprecipitated from the Rat-2 cells transformed by co-expression of these proteins. Nef also formed stable complexes with the kinase-defective and activated forms of Hck, indicating that the SH3 domains of all three Hck proteins are accessible to Nef. Control experiments show that Nef does not cross-react with the anti-Hck antibody. These experiments provide the first evidence for stable Hck-Nef complexes in intact cells. However, the possibility that the observed complexes form in solution after lysis of the cells cannot be formally ruled out. A final series of experiments investigated the dependence of Hck kinase activation and cellular transformation on the SH3-binding activity of Nef. Hck was co-expressed with a mutant of Nef in which the proline residues at positions 72 and 75 were converted to alanine (Nef-PA mutant) (20Saksela K. Cheng G. Baltimore D. EMBO J. 1995; 14: 484-491Crossref PubMed Scopus (504) Google Scholar). Mutagenesis of these prolines has been shown previously to completely block Nef-SH3 bindingin vitro (20Saksela K. Cheng G. Baltimore D. EMBO J. 1995; 14: 484-491Crossref PubMed Scopus (504) Google Scholar). Recent structural studies of Nef-SH3 complexes have confirmed that these Nef residues form part of the polyproline type II helix essential for interaction with the SH3 domain (26Grzesiek S. Bax A. Clore G.M. Gronenborn A.M. Hu J.-S. Kaufman J. Palmer I. Stahl S.J. Wingfield P.T. Nat. Struct. Biol. 1996; 3: 340-345Crossref PubMed Scopus (306) Google Scholar, 27Lee C.-H. Saksela K. Mirza U.A. Chait B.T. Kuriyan J. Cell. 1996; 85: 931-942Abstract Full Text Full Text PDF PubMed Scopus (383) Google Scholar). Co-expression of Hck with the Nef-PA mutant failed to induce transformation (Fig. 1, Table I), despite strong expression of both proteins in the co-infected cultures (Fig. 5). Furthermore, Nef-PA was unable to stimulate Hck kinase activityin vivo as assessed by tyrosine phosphorylation of the endogenous protein, p40 (Fig. 5). In addition, Hck autophosphorylation was not stimulated by this Nef mutant (data not shown). Consistent with previous in vitro work, the Nef-PA mutant was unable to bind to Hck in the co-immunoprecipitation assay (Fig. 5). Taken together, these findings strongly support the hypothesis that Nef binds directly to the SH3 domain of Hck in vivo, leading to Hck tyrosine kinase activation and cellular transformation. Data presented in this report show that engagement of a Src family kinase SH3 domain by a target protein leads to kinase activation, tyrosine phosphorylation of substrate proteins, and cellular transformation. These data provide direct new evidence that SH3 domains contribute to the negative regulation of Src family kinases in vivo. While this manuscript was being prepared for submission, the three-dimensional crystal structures of the inactive, Csk-phosphorylated forms of both c-Src and Hck were reported (28Xu W. Harrison S.C. Eck M.J. Nature. 1997; 385: 595-602Crossref PubMed Scopus (1244) Google Scholar, 29Sicheri F. Moarefi I. Kuriyan J. Nature. 1997; 385: 602-609Crossref PubMed Scopus (1043) Google Scholar). Both structures revealed the anticipated intramolecular interaction between the SH2 domain and the tyrosine-phosphorylated tail. Unexpectedly, both structures also showed an intramolecular interaction of the SH3 domain with a helical region formed by the linker connecting the SH2 and kinase domains. In light of this new structural information, the most likely mechanistic explanation for our data is that engagement of the SH3 domain by Nef disturbs this intramolecular interaction, releasing the kinase from the inactive, closed state. Such a mechanism implies that SH3-mediated activation can occur in the absence of dephosphorylation of the tail and supports a central role for the SH3 domain in negative regulation. Also supporting this view is the recent observation that Nef can stimulate Hck tyrosine kinase activity in vitro despite the presence of a phosphotyrosine residue in the tail region (30Moarefi I. LaFevre-Bernt M. Sicheri F. Huse M. Lee C.-H. Kuriyan J. Miller W.T. Nature. 1997; 385: 650-653Crossref PubMed Scopus (537) Google Scholar). SH3 domains of Src family kinases have been reported to interact with a wide variety of substrate proteins via their SH3 domains (23Briggs S.D. Bryant S.S. Jove R. Sanderson S.D. Smithgall T.E. J. Biol. Chem. 1995; 270: 14718-14724Abstract Full Text Full Text PDF PubMed Scopus (60) Google Scholar, 31Liu X. Marengere L.E.M. Koch C.A. Pawson T. Mol. Cell. Biol. 1993; 13: 5225-5232Crossref PubMed Scopus (155) Google Scholar, 32Weng Z. Thomas S.M. Rickles R.J. Taylor J.A. Brauer A.W. Seidel-Dugan C. Michael W.M. Dreyfuss G. Brugge J.S. Mol. Cell. Biol. 1994; 14: 4509-4521Crossref PubMed Scopus (206) Google Scholar, 33Weng Z. Taylor J.A. Turner C.E. Brugge J.S. Seidel-Dugan C. J. Biol. Chem. 1993; 268: 14956-14963Abstract Full Text PDF PubMed Google Scholar). Our data suggest that binding of a substrate protein to the SH3 domain may be sufficient to stimulate Src tyrosine kinase activity in vivo, possibly inducing substrate phosphorylation. Work presented here is consistent with the notion that Nef, which lacks any known catalytic function, acts by influencing kinases or other signaling pathways within the host cell (reviewed in Ref. 18Stevenson M. Nat. Struct. Biol. 1996; 3: 303-306Crossref PubMed Scopus (10) Google Scholar). Also supporting this hypothesis are previous studies of a variant of SIV that may signal by interacting with Src. However, in contrast to our data, the unusual acutely lethal phenotype of this variant (SIVpbj14; Ref. 34Fultz P.N. J. Virol. 1991; 65: 4902-4909Crossref PubMed Google Scholar) is dependent upon the presence of an SH2 recognition sequence encoded by its Nef gene that is phosphorylated by Src (35Du Z. Lang S.M. Sasseville V.G. Lackner A.A. Ilyinskii P.O. Daniel M.D. Jung J.U. Desrosiers R.C. Cell. 1995; 82: 665-674Abstract Full Text PDF PubMed Scopus (235) Google Scholar). The SIVpbj14 Nef allele was able to transform NIH3T3 cells, although the role of Src activation in the transformation event was not investigated directly (35Du Z. Lang S.M. Sasseville V.G. Lackner A.A. Ilyinskii P.O. Daniel M.D. Jung J.U. Desrosiers R.C. Cell. 1995; 82: 665-674Abstract Full Text PDF PubMed Scopus (235) Google Scholar). SH2-dependent activation of Src may not be required for HIV Nef function in general, since the SIVpbj14 Nef SH2 recognition motifs that govern its acutely pathogenic properties are not found in the Nef genes of known HIV-1 strains (36Myers G. Human Retroviruses and AIDS. Los Alamos National Laboratory, Los Alamos, NM1994Google Scholar). We were unable to detect tyrosine phosphorylation of Nef in the fibroblasts transformed by co-expression of Hck and Nef, suggesting that SH2 domain interaction is not involved in the activation mechanism (data not shown). Our data show that stimulation of Hck protein-tyrosine kinase activity by HIV-1 Nef is sufficient to produce a transformed phenotype in fibroblasts. Given the strong conservation of proline-rich motifs among various Nef alleles, these data argue that SH3-dependent activation of Src family tyrosine kinases may be a general property of primate lentiviruses. Our results, together with previous reports of the remarkable affinity and specificity of HIV-1 Nef for the Hck SH3 domain (20Saksela K. Cheng G. Baltimore D. EMBO J. 1995; 14: 484-491Crossref PubMed Scopus (504) Google Scholar, 21Lee C.H. Leung B. Lemmon M.A. Zheng J. Cowburn D. Kuriyan J. Saksela K. EMBO J. 1995; 14: 5006-5015Crossref PubMed Scopus (236) Google Scholar), strongly suggest that Hck may be a relevant target for Nef in macrophages, a major site of Hck expression (15Ziegler S.F. Marth J.D. Lewis D.B. Perlmutter R.M. Mol. Cell. Biol. 1987; 7: 2276-2285Crossref PubMed Scopus (178) Google Scholar, 16Quintrell N. Lebo R. Varmus H. Bishop J.M. Pettenati M.J. Le Beau M.M. Diaz M.O. Rowley J.D. Mol. Cell. Biol. 1987; 7: 2267-2275Crossref PubMed Scopus (202) Google Scholar, 17Holtzman D.A. Cook W.D. Dunn A.R. Proc. Natl. Acad. Sci. U. S. A. 1987; 84: 8325-8329Crossref PubMed Scopus (57) Google Scholar). While the role of macrophages in lentivirus replication and pathogenicity is unclear, recent evidence suggests that macrophage infection is necessary for the pathogenic manifestations of both HIV and SIV infection (reviewed in Ref. 37Balter M. Science. 1996; 274: 1464-1465Crossref PubMed Scopus (25) Google Scholar). Hck is rapidly induced following macrophage activation and has been implicated in multiple signaling events including phagocytosis, Fc receptor signal transduction, integrin signaling, and tumor necrosis factor release (38English B.K. Ihle J.N. Myracle A. Yi T. J. Exp. Med. 1993; 178: 1017-1022Crossref PubMed Scopus (112) Google Scholar, 39Ziegler S.F. Wilson C.B. Perlmutter R.M. J. Exp. Med. 1988; 168: 1801-1810Crossref PubMed Scopus (75) Google Scholar, 40Boulet I. Ralph S. Stanley E. Lock P. Dunn A.R. Green S.P. Phillips W.A. Oncogene. 1992; 7: 703-710PubMed Google Scholar, 41Ghazizadeh S. Bolen J.B. Fleit H.B. J. Biol. Chem. 1994; 269: 8878-8884Abstract Full Text PDF PubMed Google Scholar, 42Wang A.V. Scholl P.R. Geha R.S. J. Exp. Med. 1994; 180: 1165-1170Crossref PubMed Scopus (130) Google Scholar, 43Durden D.L. Kim H.M. Calore B. Liu Y. J. Immunol. 1995; 154: 4039-4047PubMed Google Scholar, 44Lowell C.A. Fumagalli L. Berton G. J. Cell Biol. 1996; 133: 895-910Crossref PubMed Scopus (323) Google Scholar). Further investigation should determine which, if any, of these signaling pathways are modulated by HIV infection and whether these effects are mediated through Nef-Hck interaction. We thank Dr. Owen Witte, Howard Hughes Medical Institute, UCLA, for the retroviral vectors and Dr. James A. Hoxie, University of Pennsylvania, for the anti-Nef antibody." @default.
• W2016207825 created "2016-06-24" @default.
• W2016207825 creator A5051930564 @default.
• W2016207825 creator A5056204856 @default.
• W2016207825 creator A5063343955 @default.
• W2016207825 creator A5081164152 @default.
• W2016207825 date "1997-07-01" @default.
• W2016207825 modified "2023-10-12" @default.
• W2016207825 title "SH3-mediated Hck Tyrosine Kinase Activation and Fibroblast Transformation by the Nef Protein of HIV-1" @default.
• W2016207825 cites W1495472560 @default.
• W2016207825 cites W1503880077 @default.
• W2016207825 cites W1516627479 @default.
• W2016207825 cites W1528188679 @default.
• W2016207825 cites W1530340727 @default.
• W2016207825 cites W1632819236 @default.
• W2016207825 cites W1637880666 @default.
• W2016207825 cites W1693793742 @default.
• W2016207825 cites W1749710960 @default.
• W2016207825 cites W1774422881 @default.
• W2016207825 cites W1851295704 @default.
• W2016207825 cites W1920673175 @default.
• W2016207825 cites W1923801572 @default.
• W2016207825 cites W1928233886 @default.
• W2016207825 cites W1976298092 @default.
• W2016207825 cites W1977633287 @default.
• W2016207825 cites W1982186905 @default.
• W2016207825 cites W1990218393 @default.
• W2016207825 cites W1991683855 @default.
• W2016207825 cites W1995303015 @default.
• W2016207825 cites W2002473468 @default.
• W2016207825 cites W2004975586 @default.
• W2016207825 cites W2013131507 @default.
• W2016207825 cites W2027266132 @default.
• W2016207825 cites W2029287277 @default.
• W2016207825 cites W2030608812 @default.
• W2016207825 cites W2034152669 @default.
• W2016207825 cites W2065033398 @default.
• W2016207825 cites W2065289702 @default.
• W2016207825 cites W2067358708 @default.
• W2016207825 cites W2098552577 @default.
• W2016207825 cites W2117998345 @default.
• W2016207825 cites W2122149778 @default.
• W2016207825 cites W2124132224 @default.
• W2016207825 cites W2133613945 @default.
• W2016207825 cites W2138193571 @default.
• W2016207825 cites W2289265939 @default.
• W2016207825 cites W2342218669 @default.
• W2016207825 cites W326168881 @default.
• W2016207825 cites W4237567990 @default.
• W2016207825 cites W77973074 @default.
• W2016207825 doi "https://doi.org/10.1074/jbc.272.29.17899" @default.
• W2016207825 hasPubMedId "https://pubmed.ncbi.nlm.nih.gov/9218412" @default.
• W2016207825 hasPublicationYear "1997" @default.
• W2016207825 type Work @default.
• W2016207825 sameAs 2016207825 @default.
• W2016207825 citedByCount "196" @default.
• W2016207825 countsByYear W20162078252012 @default.
• W2016207825 countsByYear W20162078252013 @default.
• W2016207825 countsByYear W20162078252014 @default.
• W2016207825 countsByYear W20162078252015 @default.
• W2016207825 countsByYear W20162078252016 @default.
• W2016207825 countsByYear W20162078252017 @default.
• W2016207825 countsByYear W20162078252018 @default.
• W2016207825 countsByYear W20162078252019 @default.
• W2016207825 countsByYear W20162078252020 @default.
• W2016207825 countsByYear W20162078252021 @default.
• W2016207825 countsByYear W20162078252022 @default.
• W2016207825 countsByYear W20162078252023 @default.
• W2016207825 crossrefType "journal-article" @default.
• W2016207825 hasAuthorship W2016207825A5051930564 @default.
• W2016207825 hasAuthorship W2016207825A5056204856 @default.
• W2016207825 hasAuthorship W2016207825A5063343955 @default.
• W2016207825 hasAuthorship W2016207825A5081164152 @default.
• W2016207825 hasBestOaLocation W20162078251 @default.
• W2016207825 hasConcept C104317684 @default.
• W2016207825 hasConcept C108636557 @default.
• W2016207825 hasConcept C159047783 @default.
• W2016207825 hasConcept C184235292 @default.
• W2016207825 hasConcept C185592680 @default.
• W2016207825 hasConcept C196347352 @default.
• W2016207825 hasConcept C202751555 @default.
• W2016207825 hasConcept C204241405 @default.
• W2016207825 hasConcept C2776165026 @default.
• W2016207825 hasConcept C2780381497 @default.
• W2016207825 hasConcept C2909867262 @default.
• W2016207825 hasConcept C3013748606 @default.
• W2016207825 hasConcept C42362537 @default.
• W2016207825 hasConcept C502942594 @default.
• W2016207825 hasConcept C55493867 @default.
• W2016207825 hasConcept C62478195 @default.
• W2016207825 hasConcept C86803240 @default.
• W2016207825 hasConcept C95444343 @default.
• W2016207825 hasConceptScore W2016207825C104317684 @default.
• W2016207825 hasConceptScore W2016207825C108636557 @default.
• W2016207825 hasConceptScore W2016207825C159047783 @default.
• W2016207825 hasConceptScore W2016207825C184235292 @default.
• W2016207825 hasConceptScore W2016207825C185592680 @default.
• W2016207825 hasConceptScore W2016207825C196347352 @default.

• next