RESUMO
Evidence showing the existence in the inner compartment of rat-heart mitochondria of AKAP121 and associated PKA is presented. Immunoblotting analysis and trypsin digestion pattern show that 90% or more of mitochondrial C-PKA, R-PKA and AKAP121 is localized in the inner mitochondrial compartment, when prepared both from isolated mitochondria or cardiomyocyte cultures. This localization is verified by measurement of the specific catalytic activity of PKA, radiolabelling of R-PKA by (32)P-phosphorylated C-PKA and of AKAP by (32)P-phosphorylated R-PKA and electron microscopy of mitochondria exposed to gold-conjugated AKAP121 antibody.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Mitocôndrias Cardíacas/metabolismo , Membranas Mitocondriais/metabolismo , Proteínas de Ancoragem à Quinase A , Animais , Linhagem Celular , Microscopia Eletrônica de Transmissão , Microscopia Imunoeletrônica , Mitocôndrias Cardíacas/ultraestrutura , Membranas Mitocondriais/ultraestrutura , Ligação Proteica , RatosRESUMO
Immunochemical and functional evidence showing the existence in the inner membrane and matrix fraction of mammalian mitochondria of serine/threonine phosphatases acting on cAMP-dependent phosphoproteins is presented. Mg(2+)-dependent Ca(2+)-inhibitable PP2C phosphatase, associated to the inner membrane, dephosphorylates the 18 kDa (NDUFS4 gene) of complex I.