v-Src SH3-enhanced interaction with focal adhesion kinase at beta 1 integrin-containing invadopodia promotes cell invasion.
In viral Src (v-Src)-transformed cells, focal adhesion kinase (FAK) associates with v-Src by combined v-Src SH2 and gain-of-function v-Src SH3 domain binding to FAK. Here we assess the significance of the Arg-95 to Trp gain-of-function mutation in the v-Src SH3 domain through comparisons of Src-/- fibroblasts transformed with either Prague C v-Src or a point mutant (v-Src-RT) containing a normal (Arg-95) SH3 domain. Both v-Src isoforms exhibited equivalent kinase activity, enhanced Src-/- cell motility, and stimulated cell growth in both low serum and soft agar. The stability of a v-Src-RT.FAK signaling complex and FAK phosphorylation at Tyr-861 and Tyr-925 were reduced in v-Src-RT- compared with v-Src-transformed cells. v-Src but not v-Src-RT promoted Src-/- cell invasion through a reconstituted Matrigel basement membrane barrier and v-Src co-localized with FAK and beta(1) integrin at invadopodia. In contrast, v-Src-RT exhibited a partial perinuclear and focal contact distribution in Src-/- cells. Adenovirus-mediated FAK overexpression promoted v-Src-RT recruitment to invadopodia, the formation of a v-Src-RT.FAK signaling complex, and reversed the v-Src-RT invasion deficit. Adenovirus-mediated inhibition of FAK blocked v-Src-stimulated cell invasion. These studies establish that gain-of-function v-Src SH3 targeting interactions with FAK at beta(1) integrin-containing invadopodia act to stabilize a v-Src.FAK signaling complex promoting cell invasion.
Hauck
Christof R
CR
Department of Immunology, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA 92037, USA.
Hsia
Datsun A
DA
Ilic
Dusko
D
Schlaepfer
David D
DD
D002459:Cell Fusion; D002461:Cell Line, Transformed; D004789:Enzyme Activation; D051416:Focal Adhesion Protein-Tyrosine Kinases; D019012:Integrin beta1 / Q000378:metabolism*; D016296:Mutagenesis; D015688:Oncogene Protein pp60(v-src) / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D011485:Protein Binding; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D018909:src Homology Domains
D019012:Integrin beta1; D020033:Protein Isoforms; D011505:Protein-Tyrosine Kinases; D051416:Focal Adhesion Protein-Tyrosine Kinases; D015688:Oncogene Protein pp60(v-src)