Role of Thr17 phosphorylation (PThr17) of phospholamban (PLB) in mechanical recovery from acidosis

FERRERO P; SAID M; VALVERDE CA; MUNDIÑA-WEILENMANN C; VITTONE L; MATTIAZZI A

Capital Federal, Argentina

Congreso; XII Meeting of the International Society for Heart Research; 2003

Latin American Section of the International Society for Heart Research.

It was suggested that the mechanical recovery (MR) from acidosis in myocytes requires PLB (DeSantiago et al, Biophys J; 2003). The role of PLB phosphorylation sites on MR was studied in Langendorff perfused rat hearts. After the initial impairment in left ventricular developed pressure (LVDP), +dP/dt and LVDP decay (t) produced by acidosis (high pCO2), a rapid MR (within 3 min) ocurred followed by a slow MR towards a steady state. PThr17 significantly increased at 1-3 min of acidosis and then returned to control values. Time of acidosis 1 min 3 min 10 min +dP/dt(% C) n=7 20.9±1.1 36.4±2.0 43.0±2.5 t (Dms of C) n=7 15.9±1.9 8.38±0.8 5.7±1.7 77)7)(n=11) P-Thr17(%)= n=4 80.3±11.4 78.4±12.3 26.8±10.3 P-Ser16(%)= n=4 22.1±9.9 22.6±9.5 11.9±4.6 = %maximal-isoproterenol site-specific phosphorylation C= control values before acidosis The association of the rapid phase of MR with maximal PThr17 suggests a role of this PLB site in the MR from acidosis.