Intracellular reactive oxygen species activate Src tyrosine kinase during cell adhesion and anchorage-dependent cell growth.
Src tyrosine kinases are central components of adhesive responses and are required for cell spreading onto the extracellular matrix. Among other intracellular messengers elicited by integrin ligation are reactive oxygen species, which act as synergistic mediators of cytoskeleton rearrangement and cell spreading. We report that after integrin ligation, the tyrosine kinase Src is oxidized and activated. Src displays an early activation phase, concurrent with focal adhesion formation and driven mainly by Tyr527 dephosphorylation, and a late phase, concomitant with reactive oxygen species production, cell spreading, and integrin-elicited kinase oxidation. In addition, our results suggest that reactive oxygen species are key mediators of in vitro and in vivo v-Src tumorigenic properties, as both antioxidant treatments and the oxidant-insensitive C245A and C487A Src mutants greatly decrease invasivity, serum-independent and anchorage-independent growth, and tumor onset. Therefore we propose that, in addition to the known phosphorylation/dephosphorylation circuitry, redox regulation of Src activity is required during both cell attachment to the extracellular matrix and tumorigenesis.
Giannoni
Elisa
E
Dipartimento di Scienze Biochimiche, Viale Morgagni 50, 50134 Firenze, Italy.
Buricchi
Francesca
F
Raugei
Giovanni
G
Ramponi
Giampietro
G
Chiarugi
Paola
P
D000818:Animals; D002448:Cell Adhesion / Q000502:physiology; D049109:Cell Proliferation; D003545:Cysteine / Q000378:metabolism; D004789:Enzyme Activation; D005109:Extracellular Matrix / Q000201:enzymology; D005260:Female; D016023:Integrins / Q000378:metabolism; D007424:Intracellular Fluid / Q000201:enzymology* / Q000378:metabolism; D051379:Mice; D008819:Mice, Nude; D041681:NIH 3T3 Cells; D015688:Oncogene Protein pp60(v-src) / Q000378:metabolism; D010084:Oxidation-Reduction; D017382:Reactive Oxygen Species / Q000378:metabolism*; D019061:src-Family Kinases / Q000378:metabolism*
D016023:Integrins; D017382:Reactive Oxygen Species; D015688:Oncogene Protein pp60(v-src); D019061:src-Family Kinases; D003545:Cysteine