scholarly journals c-Abl phosphorylates Dok1 to promote filopodia during cell spreading

2004 ◽  
Vol 165 (4) ◽  
pp. 493-503 ◽  
Author(s):  
Pamela J. Woodring ◽  
Jill Meisenhelder ◽  
Sam A. Johnson ◽  
Guo-Lei Zhou ◽  
Jeffrey Field ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Tyrosine Kinase ◽  
Actin Cytoskeleton ◽  
Adaptor Protein ◽  
Cell Spreading ◽  
Unknown Mechanism ◽  
Abl Tyrosine Kinase ◽  
Src Homology 2 ◽  
Src Homology ◽  
Src Homology 2 Domain

Filopodia are dynamic F-actin structures that cells use to explore their environment. c-Abl tyrosine kinase promotes filopodia during cell spreading through an unknown mechanism that does not require Cdc42 activity. Using an unbiased approach, we identified Dok1 as a specific c-Abl substrate in spreading fibroblasts. When activated by cell adhesion, c-Abl phosphorylates Y361 of Dok1, promoting its association with the Src homology 2 domain (SH2)/SH3 adaptor protein Nck. Each signaling component was critical for filopodia formation during cell spreading, as evidenced by the finding that mouse fibroblasts lacking c-Abl, Dok1, or Nck had fewer filopodia than cells reexpressing the product of the disrupted gene. Dok1 and c-Abl stimulated filopodia in a mutually interdependent manner, indicating that they function in the same signaling pathway. Dok1 and c-Abl were both detected in filopodia of spreading cells, and therefore may act locally to modulate actin. Our data suggest a novel pathway by which c-Abl transduces signals to the actin cytoskeleton through phosphorylating Dok1 Y361 and recruiting Nck.

scholarly journals Adaptor Protein 3BP2 Is a Potential Ligand of Src Homology 2 and 3 Domains of Lyn Protein-tyrosine Kinase

2003 ◽  
Vol 278 (27) ◽  
pp. 24912-24920 ◽  
Author(s):  
Koichiro Maeno ◽  
Kiyonao Sada ◽  
Shinkou Kyo ◽  
S. M. Shahjahan Miah ◽  
Keiko Kawauchi-Kamata ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Protein Tyrosine Kinase ◽  
Adaptor Protein ◽  
Protein Tyrosine ◽  
Src Homology 2 ◽  
Src Homology ◽  
Potential Ligand

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 The importance of Src homology 2 domain-containing leukocyte phosphoprotein of 76 kilodaltons sterile-α motif domain in thymic selection and T-cell activation

Blood ◽  
2009 ◽  
Vol 114 (1) ◽  
pp. 74-84 ◽  
Author(s):  
Shudan Shen ◽  
Jasmine Lau ◽  
Minghua Zhu ◽  
Jianwei Zou ◽  
Deirdre Fuller ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Adaptor Protein ◽  
Thymic Selection ◽  
Thymocyte Development ◽  
Sam Domain ◽  
Src Homology 2 ◽  
Src Homology ◽  
Src Homology 2 Domain

Abstract The Src homology 2 domain–containing leukocyte phosphoprotein of 76 kilodaltons (SLP-76) is a cytosolic adaptor protein essential for thymocyte development and T-cell activation. It contains a sterile-α motif (SAM) domain, 3 phosphotyrosine motifs, a proline-rich region, and a Src homology 2 domain. Whereas the other domains have been extensively studied, the role of the SAM domain in SLP-76 function is not known. To understand the function of this domain, we generated SLP-76 knockin mice with the SAM domain deleted. Analysis of these mice showed that thymocyte development was partially blocked at the double-positive to single-positive transition. Positive and negative thymic selection was also impaired. In addition, we analyzed T-cell receptor (TCR)–mediated signaling in T cells from these mutant mice. TCR-mediated inositol 1,4,5-triphosphate production, calcium flux, and extracellular signal-regulated kinase activation were decreased, leading to defective interleukin-2 production and proliferation. Moreover, despite normal association between Gads and SLP-76, TCR-mediated formation of SLP-76 microclusters was impaired by the deletion of the SAM domain. Altogether, our data demonstrated that the SAM domain is indispensable for optimal SLP-76 signaling.

scholarly journals Molecular Cloning of the cDNA Encoding pp36, a Tyrosine-phosphorylated Adaptor Protein Selectively Expressed by T Cells and Natural Killer Cells

1998 ◽  
Vol 187 (7) ◽  
pp. 1157-1161 ◽  
Author(s):  
John R. Weber ◽  
Sigurd Ørstavik ◽  
Knut Martin Torgersen ◽  
Niels Christian Danbolt ◽  
Siri F. Berg ◽  
...  
Keyword(s):  
Natural Killer ◽  
Molecular Cloning ◽  
Cell Activation ◽  
Nk Cell ◽  
Rabbit Antiserum ◽  
Adaptor Protein ◽  
Peptide Sequence ◽  
Src Homology 2 ◽  
Src Homology ◽  
Src Homology 2 Domain

Activation of T and natural killer (NK) cells leads to the tyrosine phosphorylation of pp36 and to its association with several signaling molecules, including phospholipase Cγ-1 and Grb2. Microsequencing of peptides derived from purified rat pp36 protein led to the cloning, in rat and man, of cDNA encoding a T- and NK cell–specific protein with several putative Src homology 2 domain–binding motifs. A rabbit antiserum directed against a peptide sequence from the cloned rat molecule recognized tyrosine phosphorylated pp36 from pervanadate-treated rat thymocytes. When expressed in 293T human fibroblast cells and tyrosine-phosphorylated, pp36 associated with phospholipase Cγ-1 and Grb2. Studies with GST–Grb2 fusion proteins demonstrated that the association was specific for the Src homology 2 domain of Grb-2. Molecular cloning of the gene encoding pp36 should facilitate studies examining the role of this adaptor protein in proximal signaling events during T and NK cell activation.

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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