N-type calcium channel

Calcium channel, voltage-dependent, N type, alpha 1B subunit
Available structures PDB Ortholog search: PDBe, RCSB List of PDB id codes 2LCM
Identifiers
Symbols	CACNA1B ; BIII; CACNL1A5; CACNN; Cav2.2; DYT23
External IDs	OMIM: 601012 MGI: 88296 HomoloGene: 20184 IUPHAR: 533 ChEMBL: 4478 GeneCards: CACNA1B Gene
Gene ontology Molecular function • voltage-gated calcium channel activity • calcium ion binding • protein binding • ATP binding • protein C-terminus binding • high voltage-gated calcium channel activity Cellular component • plasma membrane • voltage-gated calcium channel complex • dendrite • neuronal cell body Biological process • transport • calcium ion transport • synaptic transmission • neurotransmitter secretion • locomotory behavior • regulation of heart contraction • regulation of blood pressure • ion transmembrane transport • regulation of ion transmembrane transport • response to pain • membrane depolarization • regulation of calcium ion transport • calcium ion import • calcium ion transmembrane transport • membrane depolarization during action potential Sources: Amigo / QuickGO
Orthologs
Species	Human	Mouse
Entrez	774	12287
Ensembl	ENSG00000148408	ENSMUSG00000004113
UniProt	Q00975	O55017
RefSeq (mRNA)	NM_000718	NM_001042528
RefSeq (protein)	NP_000709	NP_001035993
Location (UCSC)	Chr 9: 137.88 – 138.12 Mb	Chr 2: 24.6 – 24.76 Mb
PubMed search	[1]	[2]

Illustration of the major elements in a prototypical synapse. Synapses allow nerve cells to communicate with one another through axons and dendrites, converting electrical impulses into chemical signals.

Neuron A (transmitting) to neuron B (receiving)

• 1. Mitochondrion
• 2. Synaptic vesicle with neurotransmitters
• 3. Autoreceptor
• 4. Synapse with neurotransmitter released (serotonin)
• 5. Postsynaptic receptors activated by neuro-transmitter (induction of a postsynaptic potential)
• 6. Calcium channel
• 7. Exocytosis of a vesicle
• 8. Recaptured neurotransmitter

The N-type calcium channel is a type of voltage-dependent calcium channel. As with other sub-types of voltage-gated calcium channel, the α₁ subunit forms the pore through which calcium enters the cell and determines most of the channel's properties. The α₁ subunit is also known as the calcium channel, voltage-dependent, N type, alpha 1B subunit (CACNA1B) or Ca_v2.2 which in humans is encoded by the CACNA1B gene.

Clinical significance

Mutations in CACNA1B are associated to Myoclonus-Dystonia syndrome .

Structure

In addition to the α₁ subunit, the following subunits are present in the N-type calcium channel:

• α₂δ – CACNA2D1, CACNA2D2
• β₁ – CACNB1
• β₃ – CACNB3
• β₄ – CACNB4

Function

N-type ('N' for "Neural-Type" ) calcium channels are found primarily at presynaptic terminals and are involved in neurotransmission. Strong depolarization by an action potential causes these channels to open and allow influx of Ca²⁺, initiating vesicle fusion and release of stored neurotransmitter. N-type channels are blocked by ω-conotoxin.

Therapeutic Potential

Blockade of the N-type calcium channel is a potential therapeutic strategy for the treatment of alcoholism. Blockade of N-type calcium channels in sensory neurons has therapeutic potential for the treatment of certain types of pain, particularly neuropathic pain. The peptide N-type calcium channel blocker ziconotide is given intrathecally for intractable pain.

Blockers

• ω-Conotoxins
• Ziconotide
• Caroverine
• Cilnidipine
• NP078585
• TROX-1
• Gabapentin
• Levetiracetam
• Lamotrigine

External links

• CACNA1B protein, human at the US National Library of Medicine Medical Subject Headings (MeSH)
• N-Type Calcium Channel at the US National Library of Medicine Medical Subject Headings (MeSH)