Identification of Cav2–PKCβ and Cav2–NOS1 complexes as entities for ultrafast electrochemical coupling

Significance Nitric oxide synthase (NOS1) and protein kinase Cβ (PKCβ), through their enzymatic activities, initiate a variety of intracellular signaling processes in the brain. For activation, both enzymes require intracellular calcium ions (Ca 2+ ), which, for NOS1, may be provided via NMDA-type glutamate receptors. Activation by voltage-gated Ca 2+ (Cav) channels has remained elusive. Here we report that both PKCβ and NOS1 form bimolecular complexes with Cav2.2 channels, thus placing themselves within less than 10 nm of a Ca 2+ source. Within the framework of the channel–enzyme complexes, PKCβ and NOS1 are reliably activated even by periods of Ca 2+ influx as short as 0.8 ms occurring during action potentials. Our results establish Cav2–enzyme complexes as molecular entities for fast and precisely timed electrochemical coupling.