Reversible activation/inactivation of the deacylation/acylation cycle in rat liver microsomes

Rat liver microsomes incorporate [14C]palmitoyl CoA into membrane phospholipids via the deacylation/acylation cycle. This activity is reversibly inactivated/activated by treatment of the microsomes with ATP, MgCl2, and 105,000 g supernatant or with 105,000 g supernatant alone. These observations suggest that the acylation cycle is controlled by a mechanism involving phosphorylation/dephosphorylation. As the pool of lysolecithin in the membranes is not altered by conditions increasing incorporation of palmitoyl CoA into phospholipid, it is probable that the site of regulation of deacylation/acylation is at the acyltransferase rather than the phospholipase.