Protein kinase C isotypes and signaling in neutrophils: Differential substrate specificities of a translocatable, calcium- and phospholipid- dependent β-protein kinase C and a novel calcium-independent, phospholipid- dependent protein kinase which is inhibited by long chain fatty acyl coenzyme A

Abstract

Neutrophils possess a classical Ca2+, phosphatidyl serine (PS) and diglyceride (DG)-dependent protein kinase C (β-PKC) which was translocatable from cytosol to membrane in response to elevated Ca2+ in the physiologic range or to pretreatment with phorbol myristate acetate (PMA). The translocatable β-PKC was purified from neutrophil membranes prepared in the presence of Ca2+, eluted with EGTA and subjected to hydroxyapatite chromatography. An 80-kDa protein possessing Ca/DG/PS-dependent histone phosphorylating activity was recognized by a monoclonal antibody to β-PKC but not to α-PKC or γ-PKC. A cytosolic kinase activity remaining after Ca2+-induced translocation of β-PKC was dependent on PS ..