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Cav1.2

calcium channel, voltage-dependent, L type, alpha 1C subunit
Synonyms: cacna1c cav1.2 ca1.2. Symbol: Cacna1c

Introductions


Voltage-gated Ca2+ channels fall in three different groups: Cav1(L-type), Cav2 (N–, P/Q–, R-types), and Cav3 (T-type) [226]. Cav1.2 is an L type, high voltage activated (HVA) calcium channel found in neurons. It is also known as a1C.

Genes


GeneID: 29716 Cacna1d calcium channel, voltage-dependent, L type, alpha 1D subunit [ Rattus norvegicus ]

Cacna1c : calcium channel, voltage-dependent, L type, alpha 1C subunit

RGD ID Chromosome Position Species
2245 4 154895691-155517389 Rat
1550302 6 118542314-119146427 Mouse
10268 12 2162416-2807115 Human

Ontologies


Accession Name Definition Evidence
GO:0016020 membrane Double layer of lipid molecules that encloses all cells, and, in eukaryotes, many organelles; may be a single or double lipid bilayer; also includes associated proteins. IEA

Interactions


Second Messanger-activated Protein Kinases

Ca2+ channels are regulated primarily by second messenger-activated protein kinases. [503]

kir/Gem

The small G-protein kir/Gem inhibits L- type Ca2+ channel activities by interacting directly with the Ca2+ channel β subunit [504].

COP9 signalosome subunit 5

COP9 signalosome subunit 5 (CSN5)/Jun activation domain-binding protein 1 (Jab1) interacts with the II–III linker of the α1C subunit. Inhibi- tion of CSN5 expression by siRNA enhanced the L-type Ca2+ currents. CSN5 regulates the cardiac L-type Ca2+ channel through protein–protein interactions. [226]

Proteins


Structures


Their pore-forming alpha 1-subunit is composed of four homologous domains formed by six transmembrane segments (S1–S6) [477]. The signal of the voltage-sensing machinery, consisting of multiple charged amino acids (located in segments S4 and adjacent structures of each domain), is transmitted to the pore region [499]. Conformational changes in pore lining S6 and adjacent segments finally lead to pore openings (activation) and closures (inactivation).

Compared with potassium channels, the pore of CaV is asymmetric, and none of the four S6 segments has a putative helixbending PXP motif. Furthermore, the conserved glycine (corresponding to position 83 in MthK, see [500]) is only present in segments IS6 and IIS6 (for review see [501]). Substituting proline for this glycine in IIS6 of CaV1.2 does not significantly affect gating [502].

IS6 and IIS6 residues contribute in a energetically coupled way to activation gating.[225]

Distributions


Expressions


In cardiac myocytes, the α1C subunit of L-type Ca2+ channels (Cav1.2) is the dominant Ca channel. [226]

Functionals


Ca2+ current through CaV1.2 channels initiates muscle con- traction, release of hormones and neurotransmitters, and affects physiological processes such as vision, hearing, and gene expression [498].

Kinetics


Whereas all voltage-gated Ca2+ channel alpha-1 subunits activate and in- activate in response to membrane depolarization, the high voltage activated CaV1 and CaV2 alpha-1 subunits operate at markedly more positive membrane potentials than low voltage activated CaV3 channel alpha-1 subunits. [227]

Models


References


[225 : 19265197]
[226 : 16483597]
[227 : 15339810]
[498 : 14657414]
[477 : 11031246]
[499 : 12721619]
[500 : 12037560]
[501 : 18849656]
[502 : 16157588]
[503 : 6131381]
[504 : 11395774]

Credits


Editor : Admin.

Contributors : Rajnish Ranjan, Michael Schartner

To cite : [Editor], [Contributors]. Accessed on [Date] Channelpedia , http://channelpedia.epfl.ch/ionchannels/80