COORDINATED ACTION OF PKA AND ERK IN CHOLESTEROL TRANSPORT ACTIVATION

PODEROSO CECILIA; GALLI SOLEDAD; MALOBERTI PAULA; PODEROSO JUAN JOSE; PODESTA ERNESTO JORGE

Pinamar, Buenos Aires

Congreso; X Congreso -Panamerican Association for Biochemistry and Molecular Biology-XLI REUNION ANUAL Sociedad Argentina de Investigación Bioquímica y Biología Molecular; 2005

We have shown a strict dependence of ERK1/2 activation for PKAactivated cholesterol transport in MA-10 Leydig cells. The goal of the present study was to analyze the interaction of PKA, ERK and StAR (Steroidogenic Acute Regulatory) protein on mitochondria isolated from MA-10 cells. The interaction of ERK1 with PKA and StAR was demonstrated by co-precipitation and Western blot of PKA and StAR from isolated mitochondria derived from stimulated cells and ERK1-GST bound to agarose. Mitochondria derived from cells transfected with either sense or antisense StAR cDNA were incubated with active or mutated inactive (Lys71 Æ Ala) ERK and catalytic PKA subunit. Mitochondrial StAR content increased after sense cDNA transfection and production of progesterone increased in the presence of PKA and wild-type ERK from 32±3 to 70±7 ng/ ml (+112%, p