CYTOPLASM CYTOSOL cholesterol ATP PPi PKA cat PKA reg cAMP PKA cat PKA reg StAR StAR PKA cat PKA reg ? MITOCHONDRIA Mitochondria pregnenolone P450scc cholesterol NUCLEUS NUCLEUS CREB StAR StAR PKA cat ATP ADP CRTRC2 CREB CRTRC2 CREB PLASMA MEMBRANE PLASMA MEMBRANE Gsα Gsβ Gsγ EP2 ADCY ADCY EP2 prostaglanine E2 EP2 prostaglanine E2 Gsα Gsβ Gsγ Gsγ Gsβ EP2 prostaglanine E2 Gsα EXTRACELLULAR SPACE EXTRACELLULAR SPACE prostaglanine E2 2 4 N:2 N:2 N:2 N:2 2:cAMP 1:cAMP ct:mRNA N:2 1:cAMP 2:cAMP ct:gene ct:mRNA P P inactive active