Structure and function of neuronal Ca2+ channels and their role in neurotransmitter release.
Electrophysiological studies of neurons reveal different Ca2+ currents designated L-, N-, P-, Q-, R-, and T-type. High-voltage-activated neuronal Ca2+ channels are complexes of a pore-forming alpha 1 subunit of about 190-250 kDa, a transmembrane, disulfide-linked complex of alpha 2 and delta subunits, and an intracellular beta subunit, similar to the alpha 1, alpha 2 delta, and beta subunits previously described for skeletal muscle Ca2+ channels. The primary structures of these subunits have all been determined by homology cDNA cloning using the corresponding subunits of skeletal muscle Ca2+ channels as probes. In most neurons, L-type channels contain alpha 1C or alpha 1D subunits, N-type contain alpha 1B subunits, P- and Q-types contain alternatively spliced forms of alpha 1A subunits, R-type contain alpha 1E subunits, and T-type contain alpha 1G or alpha 1H subunits. Association with different beta subunits also influences Ca2+ channel gating substantially, yielding a remarkable diversity of functionally distinct molecular species of Ca2+ channels in neurons.
Catterall
W A
WA
Department of Pharmacology, University of Washington, Seattle 98195-7280, USA.
D000818:Animals; D015220:Calcium Channels / Q000502:physiology*; D002135:Calcium-Binding Proteins; D008562:Membrane Glycoproteins / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D018482:Muscle, Skeletal; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009474:Neurons / Q000378:metabolism*; D018377:Neurotransmitter Agents / Q000378:metabolism*; D020033:Protein Isoforms; D050600:SNARE Proteins; D013329:Structure-Activity Relationship; D009435:Synaptic Transmission; D050857:Synaptotagmins; D033921:Vesicular Transport Proteins
D015220:Calcium Channels; D002135:Calcium-Binding Proteins; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D018377:Neurotransmitter Agents; D020033:Protein Isoforms; D050600:SNARE Proteins; D033921:Vesicular Transport Proteins; D050857:Synaptotagmins