Presynaptic Calcium Channels

Presynaptic Ca2+ entry occurs through voltage-gated Ca2+ (Ca-V) channels which are activated by membrane depolarization. Depolarization accompanies neuronal firing and elevation of Ca2+ triggers neurotransmitter release from synaptic vesicles. For synchronization of efficient neurotransmitter release, synaptic vesicles are targeted by presynaptic Ca2+ channels forming a large signaling complex in the active zone. The presynaptic Ca(V)2 channel gene family (comprising Ca(V)2.1, Ca(V)2.2, and Ca(V)2.3 isoforms) encode the pore-forming 1 subunit. The cytoplasmic regions are responsible for channel modulation by interacting with regulatory proteins. This article overviews modulation of the activity of Ca(V)2.1 and Ca(V)2.2 channels in the control of synaptic strength and presynaptic plasticity.