Probing the Tyrosine Phosphorylation State in Breast Cancer by Src Homology 2 Domain Binding

2004 ◽  
Author(s):  
Bruce J. Mayer
Keyword(s):  
Breast Cancer ◽  
Tyrosine Phosphorylation ◽  
Phosphorylation State ◽  
Src Homology 2 ◽  
Src Homology ◽  
Src Homology 2 Domain

scholarly journals The control of phosphatidylinositol 3,4-bisphosphate concentrations by activation of the Src homology 2 domain containing inositol polyphosphate 5-phosphatase 2, SHIP2

2007 ◽  
Vol 407 (2) ◽  
pp. 255-266 ◽  
Author(s):  
Ian H. Batty ◽  
Jeroen van der Kaay ◽  
Alex Gray ◽  
Joan F. Telfer ◽  
Miles J. Dixon ◽  
...  
Keyword(s):  
Growth Factor ◽  
Tyrosine Phosphorylation ◽  
Specific Activity ◽  
Protein Tyrosine Phosphatases ◽  
Fold Increase ◽  
Inositol Polyphosphate ◽  
Src Homology 2 ◽  
Pi3k Activity ◽  
Src Homology ◽  
Src Homology 2 Domain

Activation of class Ia PI3K (phosphoinositide 3-kinase) produces PtdInsP3, a vital intracellular mediator whose degradation generates additional lipid signals. In the present study vanadate analogues that inhibit PTPs (protein tyrosine phosphatases) were used to probe the mechanisms which regulate the concentrations of these molecules allowing their independent or integrated function. In 1321N1 cells, which lack PtdInsP3 3-phosphatase activity, sodium vanadate or a cell permeable derivative, bpV(phen) [potassium bisperoxo(1,10-phenanthroline)oxovanadate (V)], increased the recruitment into anti-phosphotyrosine immunoprecipitates of PI3K activity and of the p85 and p110α subunits of class Ia PI3K and enhanced the recruitment of PI3K activity stimulated by PDGF (platelet-derived growth factor). However, neither inhibitor much increased cellular PtdInsP3 concentrations, but both diminished dramatically the accumulation of PtdInsP3 stimulated by PDGF or insulin and markedly increased the control and stimulated concentrations of PtdIns(3,4)P2. These actions were accounted for by the ability of PTP inhibitors to stimulate the activity of endogenous PtdInsP3 5-phosphatase(s), particularly SHIP2 (Src homology 2 domain containing inositol polyphosphate 5-phosphatase 2) and to inhibit types I and II PtdIns(3,4)P2 4-phosphatases. Thus bpV(phen) promoted the translocation of SHIP2 from the cytosol to a Triton X-100-insoluble fraction and induced a marked (5–10-fold) increase in SHIP2 specific activity mediated by enhanced tyrosine phosphorylation. The net effect of these inhibitors was, therefore, to switch the signal output of class I PI3K from PtdInsP3 to PtdIns(3,4)P2. A key component controlling this shift in the balance of lipid signals is the activation of SHIP2 by increased tyrosine phosphorylation, an effect observed in HeLa cells in response to both PTP inhibitors and epidermal growth factor.

scholarly journals Multiple stimuli induce tyrosine phosphorylation of the Crk-binding sites of paxillin

2001 ◽  
Vol 360 (1) ◽  
pp. 57-66 ◽  
Author(s):  
Michael D. SCHALLER ◽  
Erik M. SCHAEFER
Keyword(s):  
Cell Adhesion ◽  
Tyrosine Phosphorylation ◽  
Binding Sites ◽  
Signalling Molecules ◽  
Src Homology 2 ◽  
Dependent Cell ◽  
Src Homology ◽  
Tyrosine Phosphorylated Protein ◽  
Src Homology 2 Domain

Paxillin is a focal-adhesion-associated, tyrosine-phosphorylated protein. In cells transformed by the src, crk or BCR-Abl oncogenes, the phosphotyrosine content of paxillin is elevated. In normal cells paxillin functions in signalling following integrin-dependent cell adhesion or exposure to a number of stimuli, including growth factors and neuropeptides. These stimuli induce tyrosine phosphorylation of paxillin, regulating the association of Src homology 2 domain-containing signalling molecules with paxillin. There are multiple sites of tyrosine phosphorylation on paxillin. To elucidate the role of paxillin in transducing signals in response to various stimuli, it is essential to identify all of the sites of phosphorylation on paxillin and to define which residues are phosphorylated in response to distinct stimuli. We describe two new sites of tyrosine phosphorylation on paxillin, residues at positions 40 and 88. Using paxillin variants with phenylalanine substitutions at phosphorylation sites and phospho-specific paxillin antibodies, tyrosine phosphorylation of paxillin in response to distinct stimuli was examined. The results demonstrate that Tyr31 and Tyr118, which are binding sites for Crk, are major sites of tyrosine phosphorylation following cell adhesion or stimulation with platelet-derived growth factor or angiotensin II. Thus multiple stimuli may elicit similar signalling events downstream of paxillin.

scholarly journals B Cell Adaptor Containing Src Homology 2 Domain (Bash) Links B Cell Receptor Signaling to the Activation of Hematopoietic Progenitor Kinase 1

2001 ◽  
Vol 194 (4) ◽  
pp. 529-540 ◽  
Author(s):  
Sachiyo Tsuji ◽  
Mariko Okamoto ◽  
Koichi Yamada ◽  
Noriaki Okamoto ◽  
Ryo Goitsuka ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Tyrosine Phosphorylation ◽  
Phosphorylation Site ◽  
Sh2 Domain ◽  
Hematopoietic Progenitor ◽  
Src Homology 2 ◽  
Bcr Signaling ◽  
Src Homology ◽  
Src Homology 2 Domain

The B cell adaptor containing src homology 2 domain (BASH; also termed BLNK or SLP-65), is crucial for B cell antigen receptor (BCR)-mediated activation, proliferation, and differentiation of B cells. BCR-mediated tyrosine-phosphorylation of BASH creates binding sites for signaling effectors such as phospholipase Cγ (PLCγ)2 and Vav, while the function of its COOH-terminal src homology 2 domain is unknown. We have now identified hematopoietic progenitor kinase (HPK)1, a STE20-related serine/threonine kinase, as a protein that inducibly interacts with the BASH SH2 domain. BCR ligation induced rapid tyrosine-phosphorylation of HPK1 mainly by Syk and Lyn, resulting in its association with BASH and catalytic activation. BCR-mediated activation of HPK1 was impaired in Syk- or BASH-deficient B cells. The functional SH2 domain of BASH and Tyr-379 within HPK1 which we identified as a Syk-phosphorylation site were both necessary for interaction of both proteins and efficient HPK1 activation after BCR stimulation. Furthermore, HPK1 augmented, whereas its kinase-dead mutant inhibited IκB kinase β (IKKβ) activation by BCR engagement. These results reveal a novel BCR signaling pathway leading to the activation of HPK1 and subsequently IKKβ, in which BASH recruits tyrosine-phosphorylated HPK1 into the BCR signaling complex.

scholarly journals Tyrosine Phosphorylation of Tub and Its Association with Src Homology 2 Domain-containing Proteins Implicate Tub in Intracellular Signaling by Insulin

1999 ◽  
Vol 274 (35) ◽  
pp. 24980-24986 ◽  
Author(s):  
Rosana Kapeller ◽  
Ann Moriarty ◽  
Ann Strauss ◽  
Hilde Stubdal ◽  
Kelly Theriault ◽  
...  
Keyword(s):  
Tyrosine Phosphorylation ◽  
Intracellular Signaling ◽  
Src Homology 2 ◽  
Src Homology ◽  
Src Homology 2 Domain

Functional specificity of cytoplasmic and transmembrane tyrosine kinases: identification of 130- and 75-kilodalton substrates of c-fps/fes tyrosine kinase in macrophages

1994 ◽  
Vol 14 (7) ◽  
pp. 4606-4615
Author(s):  
L B Areces ◽  
P Dello Sbarba ◽  
M Jücker ◽  
E R Stanley ◽  
R A Feldman
Keyword(s):  
Tyrosine Kinase ◽  
Tyrosine Phosphorylation ◽  
Tyrosine Kinases ◽  
Protein Tyrosine Kinase ◽  
Phosphatidylinositol 3 Kinase ◽  
Macrophage Cell ◽  
Src Homology 2 ◽  
Src Homology ◽  
Src Homology 2 Domain ◽  
Stimulating Factor

c-fps/fes encodes a 92-kDa protein-tyrosine kinase (NCP92) that is expressed at the highest levels in macrophages. To determine if c-fps/fes can mediate the action of the colony-stimulating factor 1 (CSF-1) receptor (CSF-1R) and to identify potential targets of c-fps/fes in macrophages, we have overexpressed c-fps/fes in a CSF-1-dependent macrophage cell line. A 30- to 50-fold overexpression of c-fps/fes partially released these cells from their factor dependence by a nonautocrine mechanism, and this correlated with the tyrosine phosphorylation of two proteins of 130 and 75 kDa (P130 and P75). c-fps/fes did not cause tyrosine phosphorylation or activation of CSF-1 dependent targets, including CSF-1R, Shc, and phosphatidylinositol 3-kinase, and conversely, CSF-1 did not induce tyrosine phosphorylation of P130 and P75. P75 appears to be a novel phosphotyrosyl protein, whereas P130 cross-reacts with a known substrate of v-src. P130 and P75 may be direct substrates of c-fps/fes: P130 was tightly associated with NCP92, and the src homology 2 domain of NCP92 specifically bound phosphorylated P130 and P75 but not the CSF-1-induced phosphotyrosyl proteins, consistent with the possibility that P130 and P75 are physiological targets of c-fps/fes. We conclude that although c-fps/fes can functionally substitute for CSF-1R to a certain extent, these tyrosine kinases act largely independently of each other and that P130 and P75 are novel targets whose mechanisms of action may be unrelated to the signalling pathways utilized by receptor tyrosine kinases.

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