Channelpedia

Cav1.2

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

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Introduction

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.


Experimental data


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Gene

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

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

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


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Transcript

Acc No Sequence Length Source
NM_012517 n/A n/A NCBI
NM_009781 n/A n/A NCBI
NM_001159533 n/A n/A NCBI
NM_001159534 n/A n/A NCBI
NM_001159535 n/A n/A NCBI
NM_199460 n/A n/A NCBI
NM_001129827 n/A n/A NCBI
NM_001129832 n/A n/A NCBI
NM_001129831 n/A n/A NCBI
NM_001129833 n/A n/A NCBI
NM_001129842 n/A n/A NCBI
NM_001129829 n/A n/A NCBI
NM_001129834 n/A n/A NCBI
NM_000719 n/A n/A NCBI
NM_001129837 n/A n/A NCBI
NM_001129839 n/A n/A NCBI
NM_001129836 n/A n/A NCBI
NM_001129841 n/A n/A NCBI
NM_001129835 n/A n/A NCBI
NM_001129830 n/A n/A NCBI
NM_001129843 n/A n/A NCBI
NM_001129838 n/A n/A NCBI
NM_001129846 n/A n/A NCBI
NM_001129844 n/A n/A NCBI
NM_001129840 n/A n/A NCBI
NM_001167623 n/A n/A NCBI
NM_001167624 n/A n/A NCBI
NM_001167625 n/A n/A NCBI

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Ontology

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

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Interaction

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]


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Protein


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Structure

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]


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Distribution


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Expression

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


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Functional

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].


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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]


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Model


References

226

Kameda K. et al. CSN5/Jab1 inhibits cardiac L-type Ca2+ channel activity through protein-protein interactions.
J. Mol. Cell. Cardiol., 2006 Apr , 40 (562-9).

477

Catterall WA. et al. Structure and regulation of voltage-gated Ca2+ channels.
Annu. Rev. Cell Dev. Biol., 2000 , 16 (521-55).

499

MacKinnon R. et al. The principle of gating charge movement in a voltage-dependent K+ channel.
Nature, 2003 May 1 , 423 (42-8).

500

MacKinnon R. et al. The open pore conformation of potassium channels.
Nature, 2002 May 30 , 417 (523-6).

501

Kudrnac M. et al. Pore stability and gating in voltage-activated calcium channels.
Channels (Austin), 2008 Mar-Apr , 2 (61-9).

503

Reuter H. et al. Calcium channel modulation by neurotransmitters, enzymes and drugs.
Nature, 1983 Feb 17-23 , 301 (569-74).


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Credits

Editor : Admin.

Contributors : Rajnish Ranjan, Michael Schartner

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