Phosphorylation of p125(FAK) and paxillin focal adhesion proteins in src-transformed cells with different metastatic capacity

Hamster fibroblasts transformed by Rous sarcoma virus (RSV) display differe nt metastatic potentials that are associated with specific structural featu res of the v-src oncoprotein, This diverse metastatic activity could be due to various tyrosine phosphorylation levels of specific src protein substra tes, To check this hypothesis, phosphorylation of the FAK and paxillin prot eins, involved in signal transduction pathways and known as src protein sub strates, was tested, It was shown that FAK and paxillin are hyperphosphoryl ated in the high metastatic cell lines as compared with the phosphotyrosine level of these proteins found in the low metastatic cell lines. In additio n, our data confirm that v-src protein plays a direct role in paxillin phos phorylation. (C) 1999 Federation of European Biochemical Societies.