Mechanism of the apparent cooperativity in the interaction of protein kinase C with phosphatidylserine

The physical mechanism of the apparent cooperativity displayed by protein kinase C in its interaction with phosphatidylserine was investigated. Specifically, the binding of protein kinase C betaII to large unilamellar vesicles as a function of increasing mole fraction phosphatidylserine and increasing total lipid concentrations was analyzed. Experimental results showed that protein kinase C binds multiple phosphatidylserine molecules without any interaction between potential binding sites and that diacylglycerol does not stimulate cooperativity between these sites.