scholarly journals In Vitro Tyrosine Phosphorylation of PLC-γ1 and PLC-γ2 by SRC-Family Protein Tyrosine Kinases

1993 ◽  
Vol 191 (3) ◽  
pp. 1028-1033 ◽  
Author(s):  
F. Liao ◽  
H.S. Shin ◽  
S.G. Rhee
Keyword(s):  
Tyrosine Phosphorylation ◽  
Tyrosine Kinases ◽  
Protein Tyrosine Kinases ◽  
Protein Tyrosine ◽  
Family Protein

Association between B-lymphocyte membrane immunoglobulin and multiple members of the Src family of protein tyrosine kinases

1992 ◽  
Vol 12 (5) ◽  
pp. 2315-2321
Author(s):  
M A Campbell ◽  
B M Sefton
Keyword(s):  
B Cells ◽  
B Cell ◽  
Tyrosine Kinases ◽  
B Lymphocyte ◽  
Protein Tyrosine Kinases ◽  
Cell Type ◽  
Protein Tyrosine ◽  
Membrane Immunoglobulin ◽  
Family Protein

Treatment of B lymphocytes with antibodies to membrane immunoglobulin (Ig) stimulates protein tyrosine phosphorylation. We have examined the phosphorylation in vitro of proteins associated with membrane Ig. The Src family protein tyrosine kinases p53/56lyn, p59fyn, and p56lck are associated with membrane Ig in spleen B cells and B-cell lines and undergo phosphorylation in vitro. The pattern of expression of Src family protein tyrosine kinases in B cells varied. Our studies suggest that multiple kinases can potentially interact with membrane Ig and that within any one B-cell type, all of the Src family kinases expressed can be found in association with membrane Ig. We also observed that the Ig-associated Ig alpha protein, multiple forms of Ig beta, and proteins of 100 and 25 kDa were tyrosine phosphorylated in vitro. The 100- and 25-kDa proteins remain unidentified.

scholarly journals Association between B-lymphocyte membrane immunoglobulin and multiple members of the Src family of protein tyrosine kinases.

1992 ◽  
Vol 12 (5) ◽  
pp. 2315-2321 ◽  
Author(s):  
M A Campbell ◽  
B M Sefton
Keyword(s):  
B Cells ◽  
B Cell ◽  
Tyrosine Kinases ◽  
B Lymphocyte ◽  
Protein Tyrosine Kinases ◽  
Cell Type ◽  
Protein Tyrosine ◽  
Membrane Immunoglobulin ◽  
Family Protein

Treatment of B lymphocytes with antibodies to membrane immunoglobulin (Ig) stimulates protein tyrosine phosphorylation. We have examined the phosphorylation in vitro of proteins associated with membrane Ig. The Src family protein tyrosine kinases p53/56lyn, p59fyn, and p56lck are associated with membrane Ig in spleen B cells and B-cell lines and undergo phosphorylation in vitro. The pattern of expression of Src family protein tyrosine kinases in B cells varied. Our studies suggest that multiple kinases can potentially interact with membrane Ig and that within any one B-cell type, all of the Src family kinases expressed can be found in association with membrane Ig. We also observed that the Ig-associated Ig alpha protein, multiple forms of Ig beta, and proteins of 100 and 25 kDa were tyrosine phosphorylated in vitro. The 100- and 25-kDa proteins remain unidentified.

HIV infection in vitro enhances the activity of src-family protein tyrosine kinases

AIDS ◽  
1996 ◽  
Vol 10 (11) ◽  
pp. 1191-1198 ◽  
Author(s):  
David J. Phipps ◽  
Stanley E. Read ◽  
John P. Piovesan ◽  
Gordon B. Mills ◽  
Donald R. Branch
Keyword(s):  
Hiv Infection ◽  
Tyrosine Kinases ◽  
Protein Tyrosine Kinases ◽  
Protein Tyrosine ◽  
Family Protein

scholarly journals Haemophilus ducreyi LspA Proteins Are Tyrosine Phosphorylated by Macrophage-Encoded Protein Tyrosine Kinases

2008 ◽  
Vol 76 (10) ◽  
pp. 4692-4702 ◽  
Author(s):  
Kaiping Deng ◽  
Jason R. Mock ◽  
Steven Greenberg ◽  
Nicolai S. C. van Oers ◽  
Eric J. Hansen
Keyword(s):  
Tyrosine Phosphorylation ◽  
Tyrosine Kinases ◽  
Immune Cell ◽  
Kinase Inhibitor ◽  
Divalent Cations ◽  
Site Directed Mutagenesis ◽  
Haemophilus Ducreyi ◽  
Protein Tyrosine Kinases ◽  
Protein Tyrosine

ABSTRACTThe LspA proteins (LspA1 and LspA2) ofHaemophilus ducreyiare necessary for this pathogen to inhibit the phagocytic activity of macrophage cell lines, an event that can be correlated with a reduction in the level of active Src family protein tyrosine kinases (PTKs) in these eukaryotic cells. During studies investigating this inhibitory mechanism, it was discovered that the LspA proteins themselves were tyrosine phosphorylated after wild-typeH. ducreyicells were incubated with macrophages. LspA proteins in cell-free concentratedH. ducreyiculture supernatant fluid could also be tyrosine phosphorylated by macrophages. This ability to tyrosine phosphorylate the LspA proteins was not limited to immune cell lineages but could be accomplished by both HeLa and COS-7 cells. Kinase inhibitor studies with macrophages demonstrated that the Src family PTKs were required for this tyrosine phosphorylation activity. In silico methods and site-directed mutagenesis were used to identify EPIYG and EPVYA motifs in LspA1 that contained tyrosines that were targets for phosphorylation. A total of four tyrosines could be phosphorylated in LspA1, with LspA2 containing eight predicted tyrosine phosphorylation motifs. Purified LspA1 fusion proteins containing either the EPIYG or EPVYA motifs were shown to be phosphorylated by purified Src PTK in vitro. Macrophage lysates could also tyrosine phosphorylate the LspA proteins and an LspA1 fusion protein via a mechanism that was dependent on the presence of both divalent cations and ATP. Several motifs known to interact with or otherwise affect eukaryotic kinases were identified in the LspA proteins.

scholarly journals Haemophilus ducreyi Targets Src Family Protein Tyrosine Kinases To Inhibit Phagocytic Signaling

2005 ◽  
Vol 73 (12) ◽  
pp. 7808-7816 ◽  
Author(s):  
Jason R. Mock ◽  
Merja Vakevainen ◽  
Kaiping Deng ◽  
Jo L. Latimer ◽  
Jennifer A. Young ◽  
...  
Keyword(s):  
Tyrosine Kinases ◽  
Immune Cell ◽  
Transmitted Disease ◽  
Etiologic Agent ◽  
Haemophilus Ducreyi ◽  
Protein Tyrosine Kinases ◽  
Wild Type ◽  
Protein Tyrosine ◽  
Family Protein

ABSTRACTHaemophilus ducreyi, the etiologic agent of the sexually transmitted disease chancroid, has been shown to inhibit phagocytosis of both itself and secondary targets in vitro. Immunodepletion of LspA proteins fromH. ducreyiculture supernatant fluid abolished this inhibitory effect, indicating that the LspA proteins are necessary for the inhibition of phagocytosis byH. ducreyi. Fluorescence microscopy revealed that macrophages incubated with wild-typeH. ducreyi, but not with alspA1 lspA2mutant, were unable to complete development of the phagocytic cup around immunoglobulin G-opsonized targets. Examination of the phosphotyrosine protein profiles of these two sets of macrophages showed that those incubated with wild-typeH. ducreyihad greatly reduced phosphorylation levels of proteins in the 50-to-60-kDa range. Subsequent experiments revealed reductions in the catalytic activities of both Lyn and Hck, two members of the Src family of protein tyrosine kinases that are known to be involved in the proximal signaling steps of Fcγ receptor-mediated phagocytosis. Additional experiments confirmed reductions in the levels of both active Lyn and active Hck in three different immune cell lines, but not in HeLa cells, exposed to wild-typeH. ducreyi. This is the first example of a bacte-rial pathogen that suppresses Src family protein tyrosine kinase activity to subvert phagocytic signaling in hostcells.

scholarly journals Tyrosine Phosphorylation of Pyk2 Is Selectively Regulated by Fyn During TCR Signaling

1997 ◽  
Vol 185 (7) ◽  
pp. 1253-1260 ◽  
Author(s):  
Dapeng Qian ◽  
Sima Lev ◽  
Nicolai S.C. van Oers ◽  
Ivan Dikic ◽  
Joseph Schlessinger ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Tyrosine Phosphorylation ◽  
Focal Adhesion ◽  
Tyrosine Kinases ◽  
Protein Tyrosine Kinases ◽  
Tcr Signaling ◽  
Family Protein ◽  
Tcr Signal Transduction

The Src family protein tyrosine kinases (PTKs), Lck and Fyn, are coexpressed in T cells and perform crucial functions involved in the initiation of T cell antigen receptor (TCR) signal transduction. However, the mechanisms by which Lck and Fyn regulate TCR signaling are still not completely understood. One important question is whether Lck and Fyn have specific targets or only provide functional redundancy during TCR signaling. We have previously shown that Lck plays a major role in the tyrosine phosphorylation of the TCR-ζ chain and the ZAP-70 PTK. In an effort to identify the targets that are specifically regulated by Fyn, we have studied the tyrosine phosphorylation of Pyk2, a recently discovered new member of the focal adhesion kinase family PTK. We demonstrated that Pyk2 was rapidly tyrosine phosphorylated following TCR stimulation. TCR-induced tyrosine phosphorylation of Pyk2 was selectively dependent on Fyn but not Lck. Moreover, in heterologous COS-7 cells, coexpression of Pyk2 with Fyn but not Lck resulted in substantial increases in Pyk2 tyrosine phosphorylation. The selective regulation of Pyk2 tyrosine phosphorylation by Fyn in vivo correlated with the preferential phosphorylation of Pyk2 by Fyn in vitro. Our results demonstrate that Pyk2 is a specific target regulated by Fyn during TCR signaling.

Stable association of pp60src and pp59fyn with the focal adhesion-associated protein tyrosine kinase, pp125FAK

1994 ◽  
Vol 14 (1) ◽  
pp. 147-155
Author(s):  
B S Cobb ◽  
M D Schaller ◽  
T H Leu ◽  
J T Parsons
Keyword(s):  
Focal Adhesion ◽  
Tyrosine Kinases ◽  
Protein Tyrosine Kinase ◽  
Src Family Kinases ◽  
Protein Tyrosine Kinases ◽  
Protein Tyrosine ◽  
Sh2 Domains ◽  
Embryo Cells ◽  
Stable Association

Changes in cellular growth and dramatic alterations in cell morphology and adhesion are common features of cells transformed by oncogenic protein tyrosine kinases, such as pp60src and other members of the Src family. In this report, we present evidence for the stable association of two Src family kinases (pp60src and pp59fyn) with tyrosine-phosphorylated forms of a focal adhesion-associated protein tyrosine kinase, pp125FAK. In Src-transformed chicken embryo cells, most of the pp125FAK was stably complexed with activated pp60src (e.g., pp60(527F). The stable association of pp125FAK with pp60(527F) in vivo required the structural integrity of the Src SH2 domain. The association of pp60(527F) and pp125FAK could be reconstituted in vitro by incubation of normal cell extracts with glutathione S-transferase fusion proteins containing SH2 or SH3/SH2 domains of pp60src. Furthermore, the association of isolated SH2 or SH3/SH2 domains with in vitro 32P-labeled pp125FAK protected the major site of pp125FAK autophosphorylation from digestion with a tyrosine phosphatase, indicating that the autophosphorylation site of pp125FAK participates in binding with Src. Immunoprecipitation of Src family kinases from extracts of normal chicken embryo cells revealed stable complexes of pp59fyn and tyrosine-phosphorylated pp125FAK. These data provide evidence for a direct interaction between two cytoplasmic nonreceptor protein tyrosine kinases and suggest that Src may contribute to changes in pp125FAK regulation in transformed cells. Furthermore, pp125FAK may directly participate in the targeting of pp59fyn or possibly other Src family kinases to focal adhesions in normal cells.

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