PI3K PI3K PtdIns(4,5)P2 PtdIns(3,4,5)P3 LABEL PtdIns(3,4,5)P3 AKT PDK1 LABEL PDK1 PtdIns(3,4,5)P3 PKA PKA LABEL PtdIns(3,4,5)P3 AKT PDE3B PDE3B cAMP AMP AKT active inactive active inactive P P