C. Bachelot et al., ASSOCIATION OF PHOSPHATIDYLINOSITOL 3-KINASE, VIA THE SH2 DOMAINS OF P85, WITH FOCAL ADHESION KINASE IN POLYOMA MIDDLE T-TRANSFORMED FIBROBLASTS, Biochimica et biophysica acta. Molecular cell research, 1311(1), 1996, pp. 45-52
Focal adhesion kinase (FAK), a non-receptor protein tyrosine kinase, b
ecomes activated and phosphorylated on tyrosine in cells transformed w
ith v-src. By cytoimmunofluorescence a sub-fraction of the p85 subunit
of phosphoinositide 3-kinase (PI 3-kinase) localized in focal adhesio
n plaques. We examined the possibility that FAK associates with PI 3-k
inase. In fibroblasts transformed with polyoma middle t, PI 3-kinase a
ctivity co-immunoprecipitated with pp125(FAK) using two different anti
bodies against this protein. pp125(FAK) from middle t-transformed cell
s associated with a glutathione-S-transferase fusion protein containin
g the 85-kDa subunit of phosphatidylinositol 3-kinase. Both of the SH2
domains and the SH3 domain of p85 also formed complexes with pp125(FA
K) in vitro. Phosphopeptides that bind to the SH2 domains completely b
locked the binding of full-length p85 to pp125(FAK), while a peptide t
hat binds to the SH3 domain was ineffective, indicating that the assoc
iation between p85 and pp125(FAK) is mediated by the SH2 domains of p8
5.