A FAK/Src chimera with gain-of-function properties promotes formation of large peripheral adhesions associated with dynamic actin assembly.
Formation of a complex between the tyrosine kinases FAK and Src is a key integrin-mediated signaling event implicated in cell motility, survival, and proliferation. Past studies indicate that FAK functions in the complex primarily as a "scaffold," acting to recruit and activate Src within cell/matrix adhesions. To study the cellular impact of FAK-associated Src signaling we developed a novel gain-of-function approach that involves expressing a chimeric protein with the FAK kinase domain replaced by the Src kinase domain. This FAK/Src chimera is subject to adhesion-dependent activation and promotes tyrosine phosphorylation of p130Cas and paxillin to higher steady-state levels than is achieved by wild-type FAK. When expressed in FAK -/- mouse embryo fibroblasts, the FAK/Src chimera resulted in a striking cellular phenotype characterized by unusual large peripheral adhesions, enhanced adhesive strength, and greatly reduced motility. Live cell imaging of the chimera-expressing FAK -/- cells provided evidence that the large peripheral adhesions are associated with a dynamic actin assembly process that is sensitive to a Src-selective inhibitor. These findings suggest that FAK-associated Src kinase activity has the capacity to promote adhesion integrity and actin assembly.
Siesser
Priscila M F
PM
Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-8240, USA.
Meenderink
Leslie M
LM
Ryzhova
Larisa
L
Michael
Kristin E
KE
Dumbauld
David W
DW
García
Andrés J
AJ
Kaverina
Irina
I
Hanks
Steven K
SK
D000199:Actins / Q000378:metabolism*; D000818:Animals; D002478:Cells, Cultured; D051417:Focal Adhesion Kinase 1 / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D022001:Focal Adhesions / Q000201:enzymology* / Q000235:genetics; D016391:Genes, src / Q000502:physiology; D051379:Mice; D010641:Phenotype; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000235:genetics / Q000502:physiology*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000502:physiology*; D015398:Signal Transduction / Q000235:genetics
D000199:Actins; D011993:Recombinant Fusion Proteins; D051417:Focal Adhesion Kinase 1; D016392:Proto-Oncogene Proteins pp60(c-src)