voltage-dependent Ca+2 channel alpha-1B (N type, L-type Cav2.2, CACNA1B, CACNL1A5, CACH51)

Function

• pore-forming & voltage-sensitive alpha-1 subunit of voltage-sensitive Ca+2 channel
• alpha-1B gives rise to N-type Ca+2 currents; N-type Ca+2 channels
  • belong to the 'high-voltage activated' (HVA) group
  • are blocked by omega-conotoxin-GVIA (omega-CTx-GVIA) & by omega-agatoxin-IIIA (omega-Aga-IIIA)
  • insensitive to dihydropyridines (DHP), & omega-agatoxin-IVA (omega-Aga-IVA)
• Ca+2 channels containing alpha-1B subunit may play a role in directed migration of immature neurons
• interacts with RIMS1 & RIMBP2 (putative)
• phosphorylated in vitro by CaM-kinase II, PKA, PKC & CGPK

Structure

• each of the 4 internal repeats contains 5 hydrophobic transmembrane segments (S1, S2, S3, S5, S6) & one positively charged transmembrane segment (S4)
• S4 segments probably represent the voltage-sensor & are characterized by a series of positively charged amino acids at every third position
• belongs to the Ca+2 channel alpha-1 subunit (TC 1.A.1.11) family
• contains 1 EF-hand domain

Compartment

membrane

Alternative splicing

named isoforms=2; alpha-1B-1, alpha-1B-2

Expression

• isoform alpha-1b-1 & isoform alpha-1b-2 are expressed in central nervous system, but not in skeletal muscle or aorta

More general terms

• voltage-dependent Ca+2 channel alpha-1

Additional terms

• voltage-dependent Ca+2 channel

Component of

• N-type Ca+2 channel or neuronal-type Ca+2 channel
• L-type Ca+2 channel, long duration or slowly inactivating Ca+2 channel or dihydropyridine receptor (R-type Ca+2 channel)

Database

• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=774
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:774
• OMIM: https://mirror.omim.org/entry/601012
• UniProt: http://www.uniprot.org/uniprot/Q00975.html