LTCC multimer transports Ca2+ from extracellular region to cytosol

Stable Identifier
Reaction [transition]
Homo sapiens
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Voltage-dependent L-type calcium channels (LTCCs) transport Ca2+ into excitable cells. Isoforms CACNA1C, D, F and S form long-lasting (L-type) inward Ca2+ currents (ICaL) and play an important role in excitation-contraction coupling in the heart. LTCCs are multisubunit complexes consisting of alpha-1, alpha-2/delta, beta and gamma subunits in a 1:1:1:1 ratio (Brust et al. 1993). The alpha-2 and delta subunits in these complexes are chains of differing length cleaved from the same gene product (CACNA2D), linked by a disulfide bond (Calderon-Rivera et al. 2012). Pore-forming alpha1 subunits are supported by the auxiliary alpha-2, delta and beta subunits which aid the membrane trafficking of the alpha1 subunit and modulate the kinetic properties of the channel (Klugbauer et al. 2003, Yang et al. 2011). The binding of various gamma subunits to alpha1 subunits may differentially modulate alpha1 subunit function in the heart (Yang et al. 2011). In heart pacemaker cells, phase 0 of the action potential depends upon LTCC-mediated Ca2+ current rather than the fast Na+ current. In cardiac pacemaker cells, phase 1 is due to the closure of LTCCs (and rapid efflux of K+). Specific subunits can form the LTCC in the heart are CACNA1C (pore-forming alpha subunit), CACNA2D2 (alpha-2:delta-2 subunit), CACNB1 and CANCNB2 (either of these beta subunits) and CACNG4, 6, 7 and 8 (any of these gamma subunits).
Literature References
PubMed ID Title Journal Year
21127204 Cardiac L-type calcium channel (Cav1.2) associates with gamma subunits

Marx, SO, Yang, L, Morrow, JP, Doshi, D, Katchman, A

FASEB J. 2011
8107964 Human neuronal voltage-dependent calcium channels: studies on subunit structure and role in channel assembly

Schoonmaker, S, Simerson, S, Johnson, EC, Brust, PF, Harpold, MM, Ellis, SB, Williams, ME, Deal, CR, Veliçelebi, G, McCue, AF

Neuropharmacology 1993
15000524 Calcium channel alpha2delta subunits: differential expression, function, and drug binding

Klugbauer, N, Marais, E, Hofmann, F

J. Bioenerg. Biomembr. 2003
22054663 Identification of a disulfide bridge essential for structure and function of the voltage-gated Ca(2+) channel ?(2)?-1 auxiliary subunit

Rivera, M, Gomora, JC, Calderón-Rivera, A, Felix, R, González-Ramírez, R, Andrade, A, Sandoval, A, Hernández-Hernández, O

Cell Calcium 2012
Catalyst Activity

voltage-gated calcium channel activity of LTCC multimer [plasma membrane]

Orthologous Events
Cross References
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