Activation of SRC family kinases in human neutrophils. Evidence that p58c‐frg and p53/56lyn redistributed to a Triton X‐100‐insoluble cytoskeletal fraction, also enriched in the caveolar protein Caveolin, display an enhanced kinase activity

FEBS Letters

Fumagalli, Laura¹  Berton, Giorgio¹ 

[1] Institute of General Pathology, University of Verona, Strada le Grazie 8, 37134 Verona, Italy

关键词: 58c−fgr;    p53/56lyn;    Tyrosine phosphorylation;    Neutrophil;    Cytoskeleton;    Caveolae;   

DOI  :  10.1016/0014-5793(96)00029-4

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Protein tyrosine phosphorylation is one of the signals involved in stimulation of neutrophil (PMN) functions. We found that phorbol myristate acetate (PMA) activates the src family tyrosine kinases p58^c−fgr and p53/56^lyn in suspended PMNs. Moreover, we found that up to about 20% of p58^c−fgr and p53/56^lyn redistribute to a Triton X-100-insoluble fraction after PMA stimulation, and it is this fraction of the two kinases which displays an increased activity. These changes of p58^c−fgr and p53/56^lyn distribution and activity correlated with tyrosine phosphorylation of endogenous substrates. In fact, in PMA-stimulated PMNs tyrosine phosphorylated proteins are mostly recovered in a Triton-insoluble cell fraction. To separate cytoskeletal from caveolar structures, which both display Triton X-100-insolubility, we used the detergent n-octyl ß-d-glucopyranoside (OGP) which solubilises components of caveolae. We found that the caveolae marker protein, caveolin, as well as the cytoskeletal protein α-actinin and p58^c−fgr and p53/56^lyn, is insoluble in OGP. These findings suggest that PMA stimulation promotes the formation of multimolecular complexes containing cytoskeletal proteins, caveolin-containing structures and src family protein tyrosine kinases. Moreover, they show that p58^c−fgr and p53/56^lyn associated with this multimolecular complex display an enhanced kinase activity.

【 授权许可】

Unknown