Protein Domain : IPR002077

Type:  Family Name:  Voltage-dependent calcium channel, alpha-1 subunit
Description:  Ca2+ ions are unique in that they not only carry charge but they are also the most widely used of diffusible second messengers. Voltage-dependent Ca2+ channels (VDCC) are a family of molecules that allow cells to couple electrical activity to intracellular Ca2+ signalling. The opening and closing of these channels by depolarizing stimuli, such as action potentials, allows Ca2+ ions to enter neurons down a steep electrochemical gradient, producing transient intracellular Ca2+ signals. Many of the processes that occur in neurons, including transmitter release, gene transcription and metabolism are controlled by Ca2+ influx occurring simultaneously at different cellular locales. The pore is formed by the alpha-1 subunit which incorporates the conduction pore, the voltage sensor and gating apparatus, and the known sites of channel regulation by second messengers, drugs, and toxins []. The activity of this pore is modulated by 4 tightly-coupled subunits: an intracellular beta subunit; a transmembrane gamma subunit; and a disulphide-linked complex of alpha-2 and delta subunits, which are proteolytically cleaved from the same gene product. Properties of the protein including gating voltage-dependence, G protein modulation and kinase susceptibility can be influenced by these subunits.Voltage-gated calcium channels are classified as T, L, N, P, Q and R, and are distinguished by their sensitivity to pharmacological blocks, single-channel conductance kinetics, and voltage-dependence. On the basis of their voltage activation properties, the voltage-gated calcium classes can be further divided into two broad groups: the low (T-type) and high (L, N, P, Q and R-type) threshold-activated channels.The alpha-1 subunit forms the pore for the import of extracellular calcium ions and, though regulated by the other subunits, is primarily responsible for the pharmacological properties of the channel []. It shares sequence characteristics with all voltage-dependent cation channels, and exploits the same 6-helix bundle structural motif - in both sodium and calcium channels, this motif is repeated 4 times within the sequence to give a 24-helix bundle. Within each of these repeats, 5 of the transmembrane (TM) segments (S1, S2, S3, S5, S6) are hydrophobic, while the other (S4) is positively charged and serves as the voltage-sensor. Several genes encoding alpha-1 subunits have been identified and can be divided into three functionally distinct families based on sequence homology - Cav1, Cav2 and Cav3 []. The Cav1 family forms channels mediating L-type calcium currents, the Cav2 family mediates P/Q-, N-, and R-type calcium currents, while the Cav3 family mediates T-type calcium currents.This entry represents all types of alpha-1 subunit. Short Name:  VDCCAlpha1
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5 Child Features

DB identifier Type Name
IPR005448 Family Voltage-dependent calcium channel, P/Q-type, alpha-1 subunit
IPR005447 Family Voltage-dependent calcium channel, N-type, alpha-1 subunit
IPR005449 Family Voltage-dependent calcium channel, R-type, alpha-1 subunit
IPR005445 Family Voltage-dependent calcium channel, T-type, alpha-1 subunit
IPR005446 Family Voltage-dependent calcium channel, L-type, alpha-1 subunit

1 Contains

DB identifier Type Name
IPR005821 Domain Ion transport domain

1 Cross References

Identifier
PR00167

0 Found In

3 GO Annotations

GO Term Gene Name
GO:0005245 IPR002077
GO:0070588 IPR002077
GO:0005891 IPR002077

3 Ontology Annotations

GO Term Gene Name
GO:0005245 IPR002077
GO:0070588 IPR002077
GO:0005891 IPR002077

0 Parent Features

16 Proteins

DB identifier UniProt Accession Secondary Identifier Organism Name Length
48447 C1N208 PAC:27339370 Micromonas pusilla CCMP1545 1928  
21063 C1N2B7 PAC:27339609 Micromonas pusilla CCMP1545 1350  
32293 C1MLS9 PAC:27347321 Micromonas pusilla CCMP1545 1405  
95305 C1FH96 PAC:27397511 Micromonas sp RCC299 1436  
105920 C1FFJ7 PAC:27403128 Micromonas sp RCC299 1877  
82714 C1E9G5 PAC:27402424 Micromonas sp RCC299 1469  
61641 C1ED37 PAC:27401509 Micromonas sp RCC299 1877  
45407 A4RW52 PAC:27415661 Ostreococcus lucimarinus 938  
13647 A4RQQ5 PAC:27417851 Ostreococcus lucimarinus 1546  
32140 A4RYT5 PAC:27418268 Ostreococcus lucimarinus 1701  
Cre16.g665050.t1.2 B9A0U9 PAC:30777353 Chlamydomonas reinhardtii 2062  
Cre17.g702850.t1.1 A0A2K3CP21 PAC:30781610 Chlamydomonas reinhardtii 4863  
Cre17.g720600.t1.1 A0A2K3CQ96 PAC:30782719 Chlamydomonas reinhardtii 2253  
Mapoly0016s0197.1.p A0A2R6XGB8 PAC:33027192 Marchantia polymorpha 1757  
Cz08g19170.t1 PAC:38244841 Chromochloris zofingiensis 1003  
Vocar.0066s0019.1.p PAC:32891735 Volvox carteri 2165  

3 Publications

First Author Title Year Journal Volume Pages PubMed ID
            14657414
            11031246
            10774722