Stimulation of brain membrane protein phosphorylation by calcium and an endogenous heat-stable protein

摘要: THE important role of Ca2+ in the physiology nervous system is well documented1,2. However, biochemical mechanisms underlying certain its physiological effects, such as stimulus–secretion coupling3,4 and synthesis cate-cholamines5,6, have not yet been elucidated. Calcium has implicated several reactions potential importance to synaptic function. Thus, calcium a heat-stable calcium-binding protein activate cyclic nucleotide phosphodiesterase from mammalian brain7,8. The calcium-dependent regulator (CDR) porcine brain9, bovine heart10 brain11 purified characterised. CDR seems be receptor it binds strongly specifically. There evidence that CDR·Ca2+ complex true activator phosphodiesterase12–14. A detergent-solubilised preparation brain adenylate cyclase can also activated by this protein15. stimulates phosphorylation both intact16,17 lysed18,19 synaptosomes nucleotide-independent mechanism may mediate or modulate some intracellular effects on function presynaptic nerve terminals. We report here synaptosomal membrane fractions rat cerebral cortex requires an endogenous factor present cytoplasm. stimulated lost purification membranes effectively recovered reconstitution with either cytoplasm CDR. regulation kinase activity mediated physiologically postulated regulate cyclase.