Platelet-derived Growth Factor (PDGF) Regulates Slingshot Phosphatase Activity via Nox1-dependent Auto-dephosphorylation of Serine 834 in Vascular Smooth Muscle Cells

Maheswaranathan, Mithunan; Gole, Hope K. A.; Fernandez, Isabel; Lassegue, Bernard; Griendling, Kathy K.; San Martin, Alejandra

Abstract

Migration of vascular smooth muscle cells (VSMCs) contributes to vascular pathology. PDGF induces VSMC migration by a Nox1-based NADPH oxidase mediated mechanism. We have previously shown that PDGF-induced migration in VSMCs requires Slingshot-1L (SSH1L) phosphatase activity. In the present work, the mechanism of SSH1L activation by PDGF is further investigated. We identified a 14-3-3 consensus binding motif encompassing Ser-834 in SSH1L that is constitutively phosphorylated. PDGF induces SSH1L auto-dephosphorylation at Ser-834 in wild type (wt), but not in Nox1(-/y) cells. A SSH1L-S834A phospho-deficient mutant has significantly lower binding capacity for 14-3-3 when compared with the phospho-mimetic SSH1L-S834D mutant, and acts as a constitutively active phosphatase, lacking of PDGF-mediated regulation. Given that Nox1 produces reactive oxygen species, we evaluated their participation in this SSH1L activation mechanism. We found that H2O2 activates SSH1L and this is accompanied by SSH1L/14-3-3 complex disruption and 14-3-3 oxidation in wt, but not in Nox1(-/y) cells. Together, these data demonstrate that PDGF activates SSH1L in VSMC by a mechanism that involves Nox1-mediated oxidation of 14-3-3 and Ser-834 SSH1L auto-dephosphorylation.

Más información

Título según WOS: ID WOS:000295927100014 Not found in local WOS DB
Título de la Revista: JOURNAL OF BIOLOGICAL CHEMISTRY
Volumen: 286
Número: 41
Editorial: AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC
Fecha de publicación: 2011
Página de inicio: 35430
Página final: 35437
DOI:

10.1074/jbc.M111.268284

Notas: ISI