Shp2 negatively regulates growth in cardiomyocytes by controlling focal adhesion kinase/Src and mTOR pathways

Autor(es)

Marin, Talita M. ^[1] ; Clemente, Carolina F. M. Z. ^[1] ; Santos, Aline M. ^[1] ; Picardi, Paty K. ^[1] ; Pascoal, Vinicius D. B. ^[2] ; Lopes-Cendes, Iscia ^[2] ; Saad, Mario J. A. ^[1] ; Franchini, Kleber G. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Estadual Campinas, Fac Med Sci, Dept Internal Med, Sao Paulo - Brazil

^[2] Univ Estadual Campinas, Fac Med Sci, Dept Med Genet, Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Circulation Research; v. 103, n. 8, p. 813-U90, OCT 10 2008.
• Citações Web of Science: 40

Resumo

The aim of this study was to investigate whether Shp2 (Src homology region 2, phosphatase 2) controls focal adhesion kinase (FAK) activity and its trophic actions in cardiomyocytes. We show that low phosphorylation levels of FAK in nonstretched neonatal rat ventricular myocytes (NRVMs) coincided with a relatively high basal association of FAK with Shp2 and Shp2 phosphatase activity. Cyclic stretch (15% above initial length) enhanced FAK phosphorylation at Tyr397 and reduced FAK/Shp2 association and phosphatase activity in anti-Shp2 precipitates. Recombinant Shp2 C-terminal protein tyrosine phosphatase domain (Shp2-PTP) interacted with nonphosphorylated recombinant FAK and dephosphorylated FAK immunoprecipitated from NRVMs. Depletion of Shp2 by specific small interfering RNA increased the phosphorylation of FAK Tyr397, Src Tyr418, AKT Ser473, TSC2 Thr1462, and S6 kinase Thr389 and induced hypertrophy of nonstretched NRVMs. Inhibition of FAK/Src activity by PP2 [4-amino-5-(4-chlorophenyl)-7-( t-butyl) pyrazolo{[}3,4-d] pyrimidine] abolished the phosphorylation of AKT, TSC2, and S6 kinase, as well as the hypertrophy of NRVMs induced by Shp2 depletion. Inhibition of mTOR (mammalian target of rapamycin) with rapamycin blunted the hypertrophy in NRVMs depleted of Shp2. NRVMs treated with PP2 or depleted of FAK by specific small interfering RNA were defective in FAK, Src, extracellular signal-regulated kinase, AKT, TSC2, and S6 kinase phosphorylation, as well as in the hypertrophic response to prolonged stretch. The stretch-induced hypertrophy of NRVMs was also prevented by rapamycin. These findings demonstrate that basal Shp2 tyrosine phosphatase activity controls the size of cardiomyocytes by downregulating a pathway that involves FAK/Src and mTOR signaling pathways. (AU)

• Processo FAPESP: 06/54878-3 - Patogênese da hipertrofia e insuficiência cardíacas: mecanismos ativados por estimulo mecânico
• Beneficiário: Kleber Gomes Franchini
• Linha de fomento: Auxílio à Pesquisa - Temático
• Processo FAPESP: 06/55920-3 - Efeito do silenciamento da tirosino-fosfatase SHP-2 nas alterações fenotípicas dos miócitos cardíacos e coração de camundongos submetidos a estresse mecânico
• Beneficiário: Talita Miguel Marin
• Linha de fomento: Bolsas no Brasil - Doutorado
• Processo FAPESP: 04/10167-0 - Influência da quinase de adesão focal na hipertrofia miocárdica induzida por sobrecarga pressora em corações de camundongos
• Beneficiário: Carolina Fernanda Manfredi Zambon Clemente
• Linha de fomento: Bolsas no Brasil - Doutorado