An active Src kinase-beta-actin association is linked to actin dynamics at the periphery of colon cancer cells.
Src controls the dynamic actin cytoskeleton in fibroblasts and in cancer cells, although it is not known how direct its effects are. Using FRET/FLIM imaging, we found that wild type Src associates directly, or indirectly, with peripheral beta-actin at integrin adhesions after serum stimulation, and that an active Src kinase domain is essential. Beta-actin can be directly tyrosine-phosphorylated by Src in vitro, and in a Src-dependent manner in cells. Moreover, beta-actin dynamics are suppressed when Src is rendered kinase-inactive. Surprisingly, debilitating mutations in the Src SH2 or SH3 domains do not suppress association of Src with beta-actin. This may therefore be an example of a spatially regulated Src kinase/substrate interaction that is controlling peripheral actin dynamics. Interestingly, there is no FRET between Src and beta-actin at cadherin-mediated cell-cell contacts, despite apparent co-localization there, demonstrating precise spatial specificity of Src/beta-actin complexes.
Avizienyte
Egle
E
The Beatson Institute for Cancer Research, Cancer Research UK Beatson Laboratories, Garscube Estate, Switchback Road, Glasgow G61 1BD, Scotland, UK.
Keppler
Melanie
M
Sandilands
Emma
E
Brunton
Valerie G
VG
Winder
Steve J
SJ
Ng
Tony
T
Frame
Margaret C
MC
D000199:Actins / Q000378:metabolism / Q000502:physiology*; D000595:Amino Acid Sequence; D002450:Cell Communication; D045744:Cell Line, Tumor; D003110:Colonic Neoplasms; D003598:Cytoskeletal Proteins / Q000378:metabolism; D003599:Cytoskeleton / Q000378:metabolism; D004789:Enzyme Activation; D031541:Fluorescence Resonance Energy Transfer; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation; D010766:Phosphorylation; D011485:Protein Binding; D015398:Signal Transduction; D018909:src Homology Domains; D019061:src-Family Kinases / Q000235:genetics / Q000378:metabolism*
D000199:Actins; D003598:Cytoskeletal Proteins; D019061:src-Family Kinases