Multiple Ca 2+signaling pathways converge on CaM kinase in PC12 cells

The role of multifunctional Ca 2+/calmodulin-dependent protein kinase (CaM kinase) in mediating various Ca 2+signaling pathways was examined in PC12 cells. Conversion of the kinase to a Ca 2+-independent form was used to monitor which neurotransmitters activate the enzyme in situ. CaM kinase responds to Ca 2+influx elicited by ligand-gated Ca 2+channels for ATP and acetylcholine. It also responds to Ca 2+mobilization ofIP 3-sensitive stores elicited by phospholipase C-linked receptors for ATP and acetylcholine as well as by caffeine. CaM kinase mediates the actions of many neurotransmitters and Ca 2+signaling pathways.