This portal has not been updated since October 2011. Please use the new PC2 web services.
Send us your feedback.  Sign up for Pathway Commons announcements.  RSS Logo RSS Feed

Protein: CAC1A_HUMAN

Voltage-dependent P/Q-type calcium channel subunit alpha-1A

FUNCTION: Voltage-sensitive calcium channels (VSCC) mediate the entry of calcium ions into excitable cells and are also involved in a variety of calcium-dependent processes, including muscle contraction, hormone or neurotransmitter release, gene expression, cell motility, cell division and cell death. The isoform alpha-1A gives rise to P and/or Q-type calcium currents. P/Q-type calcium channels belong to the 'high-voltage activated' (HVA) group and are blocked by the funnel toxin (Ftx) and by the omega-agatoxin- IVA (omega-Aga-IVA). They are however insensitive to dihydropyridines (DHP), and omega-conotoxin-GVIA (omega-CTx-GVIA). more...

SUBUNIT: Voltage-dependent calcium channels are multisubunit complexes, consisting of alpha-1, alpha-2, beta and delta subunits in a 1:1:1:1 ratio. The channel activity is directed by the pore- forming and voltage-sensitive alpha-1 subunit. In many cases, this subunit is sufficient to generate voltage-sensitive calcium channel activity. The auxiliary subunits beta and alpha-2/delta linked by a disulfide bridge regulate the channel activity. Interact (via C-terminal CDB motif) with CABP1 in the pre- and postsynaptic membranes.

SUBCELLULAR LOCATION: Membrane; Multi-pass membrane protein.

ALTERNATIVE PRODUCTS: Event=Alternative splicing; Named isoforms=7; Comment=Additional isoforms seem to exist; Name=1; Synonyms=1A-1, BI-1-GGCAG; IsoId=O00555-1; Sequence=Displayed; Name=2; Synonyms=1A-2,BI-1; IsoId=O00555-2; Sequence=VSP_000875; Name=3; Synonyms=BI-1(V1); IsoId=O00555-3; Sequence=VSP_000871, VSP_000875; Name=4; Synonyms=BI-1(V1)-GGCAG; IsoId=O00555-4; Sequence=VSP_000871; Name=5; Synonyms=BI-1(V2); IsoId=O00555-5; Sequence=VSP_000872, VSP_000875; Name=6; Synonyms=BI-1(V2)-GGCAG; IsoId=O00555-6; Sequence=VSP_000872; Name=7; Synonyms=BI-1(V2,V3); IsoId=O00555-7; Sequence=VSP_000873, VSP_000874;

TISSUE SPECIFICITY: Brain specific; mainly found in cerebellum, cerebral cortex, thalamus and hypothalamus. Expressed in the small cell lung carcinoma cell line SCC-9. No expression in heart, kidney, liver or muscle. Purkinje cells contain predominantly P- type VSCC, the Q-type being a prominent calcium current in cerebellar granule cells.

DOMAIN: Each of the four internal repeats contains five hydrophobic transmembrane segments (S1, S2, S3, S5, S6) and one positively charged transmembrane segment (S4). S4 segments probably represent the voltage-sensor and are characterized by a series of positively charged amino acids at every third position. POLYMORPHISM: The poly-Gln region of CACNA1A is polymorphic: 6 to 17 repeats in the normal population, expanded to about 21 to 30 repeats in SCA6. Repeat expansion has been reported also in a EA2 family.

DISEASE: Defects in CACNA1A are the cause of spinocerebellar ataxia type 6 (SCA6) [MIM:183086]. Spinocerebellar ataxia is a clinically and genetically heterogeneous group of cerebellar disorders. Patients show progressive incoordination of gait and often poor coordination of hands, speech and eye movements, due to degeneration of the cerebellum with variable involvement of the brainstem and spinal cord. SCA6 is mainly caused by expansion of a CAG repeat in the coding region of CACNA1A. There seems to be a correlation between the repeat number and earlier onset of the disorder.

DISEASE: Defects in CACNA1A are the cause of migraine familial hemiplegic type 1 (FHM1) [MIM:141500]; also known as migraine familial hemiplegic 1 (MHP1). FHM1, a rare autosomal dominant subtype of migraine with aura, is associated with ictal hemiparesis and, in some families, progressive cerebellar atrophy.

DISEASE: Defects in CACNA1A are the cause of episodic ataxia type 2 (EA2) [MIM:108500]; also known as acetazolamide-responsive hereditary paroxysmal cerebellar ataxia (APCA). EA2 is an autosomal dominant disorder characterized by acetozolamide- responsive attacks of ataxia, migraine-like symptoms, interictal nystagmus, and cerebellar atrophy.

SIMILARITY: Belongs to the calcium channel alpha-1 subunit (TC 1.A.1.11) family. CACNA1A subfamily. WEB RESOURCE: Name=GeneReviews; URL="http://www.ncbi.nlm.nih.gov/sites/GeneTests/lab/gene/CACNA1A";

GENE SYNONYMS: CACH4 CACN3 CACNL1A4.

COPYRIGHT: Protein annotation is derived from the UniProt Consortium (http://www.uniprot.org/). Distributed under the Creative Commons Attribution-NoDerivs License.

 

Organism:

  • Homo sapiens

Gene Symbol:

  • CACNA1A

Synonyms:

  • Brain calcium channel I
  • Calcium channel, L type, alpha-1 polypeptide isoform 4
  • BI
  • Voltage-gated calcium channel subunit alpha Cav2.1

Neighborhood Map:

  Loading...

Stable Link:

  • Link to this page
    Link to this page
    Paste link in email or IM:
    Paste HTML to embed in website:
Filter by Data Source:
  • All Data Sources
Filter by Organism:
  • All Organisms

[Update Filter Settings]