CA2+ CALMODULIN AND CA2+ PHOSPHOLIPID-DEPENDENT PROTEIN-KINASES IN THE NEURAL TISSUE OF THE HONEYBEE APIS-MELLIFERA

The Ca2+/calmodulin and Ca2+/phospholipid-dependent protein kinases have been purified and characterized from neural tissue of the honeybee Apis mellifera. Ca2+/calmodulin-dependent protein kinase appeared as a multisubunit complex composed of three subunits that co-migrate with kinase activity during all purification steps. The three subunits had molecular weights of 52,000, 57,000 and 60,000, termed alpha, beta' and beta, respectively. The alpha and beta-subunits are distinct peptides whereas beta' may have been generated from beta by proteolysis. The Ca2+/calmodulin-dependent protein kinase required 0.1-mu-M calmodulin and about 1-mu-M Ca2+ for half-maximal activation. The Ca2+/phospholipid-dependent protein kinase (protein kinase C) was purified from honeybee neural tissue by using DEAE-Sephacel and phosphatidylserine-affinity chromatography. The molecular weight of the protein kinase C was about 80,000 as estimated by gelfiltration. Subjection to SDS-PAGE gave a single band with M(r) = 80,000, indicating that the enzyme exists as a monomer. The enzyme was fully activated by diacylglycerol in the presence of phospholipid and Ca2+.