title: Proteolysis of protein kinase C by calpain: effect of acidic phospholipids.
abstract: The effect of acidic phospholipids on proteolysis of protein kinase C (PKC) by mu-calpain was examined at Ca++ concentrations ranging from 10(-7) to 10(-4) M. The gamma species, among the molecular species of PKC, was more susceptible to calpain than the alpha and beta (beta I/beta II) and was hydrolysed at Ca++ concentrations greater than or equal to 10(-6) M. Acidic phospholipids enhanced proteolysis of PKC gamma and lowered Ca++ concentrations required for it to the level below 10(-6) M. Among the phospholipids tested, phosphatidylinositol-bisphosphate showed the most prominent effect; phosphatidylinositol and phosphatidylserine were less effective. Polyphosphoinositides, hence, may constitute an essential structure in cell membranes for positive regulation of calpain activity.
authors.affiliation: Department of Molecular Biology, Tokyo Metropolitan Institute of Medical Science, Japan.
authors.forename: T C
authors.initials: TC
authors.lastname: Saido
authors.forename: K
authors.initials: K
authors.lastname: Mizuno
authors.forename: K
authors.initials: K
authors.lastname: Suzuki
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D002154:Calpain / Q000145:classification / Q000378:metabolism*; D002417:Cattle; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D019269:Phosphatidylinositol 4,5-Diphosphate; D010716:Phosphatidylinositols / Q000494:pharmacology; D010743:Phospholipids / Q000494:pharmacology*; D011493:Protein Kinase C / Q000378:metabolism*; D011817:Rabbits
chemical_list: D019269:Phosphatidylinositol 4,5-Diphosphate; D010716:Phosphatidylinositols; D010743:Phospholipids; D011493:Protein Kinase C; D002154:Calpain; D002118:Calcium