Phosphatidylglycerol is a novel activator of nuclear protein kinase

A major mechanism by which protein kinase C (PKC) isotype fanction is regulated is the selective targeting and activation of isotypes at distinct sub-cellular locatons. PKC is selectivaly rargeted of the medeus at G ₂ phase of cell cycle where it is required for entry into cutosis. Selective nuclear translocation of PKC is conferred by molecular deterninats in the carboxyl terminal catalytic domain of the kinase Walker SD, Murray, NR. Burns. DJ and Fields. AP (1995) PN AS 92;9156-9;60]. We previously reported the presence of a lipid like activator of PKC in the nuclear membrane. Termed nu now identify NMAF as phosphatidylg based on several of evidence. First. NMAF activity confractionates with PG as a single peak of activity through multiple chromatograpy steps. Scon purified PG. but not other phospholipids. exhibit NMAF activity. Third. NMAF and purified PG display a similar pattern of susceptibility to degradation by various phospholipases. Finally differentr nuclecular specic of PG vary in their ability to activate B₁₁PKC suggesting that the falty acid side chains as well as the glycerol head group are important for activity. Taken together data in dicate that specific molecuar species of PG in the nuclear meabane serve to regulate nuclear PKC activity duting cell cycle. Supported by NIH grant RO A56869 to APE is a scholar of the Leukerila Society of America.