ORAI1

ORAI1
Available structures PDB Ortholog search: PDBe RCSB List of PDB id codes 2MAK, 4EHQ
Identifiers
Aliases	ORAI1, CRACM1, IMD9, ORAT1, TAM2, TMEM142A, ORAI calcium release-activated calcium modulator 1
External IDs	MGI: 1925542 HomoloGene: 13117 GeneCards: ORAI1
Gene ontology Molecular function • store-operated calcium channel activity • calcium channel activity • calmodulin binding • protein binding • identical protein binding Cellular component • integral component of membrane • membrane • plasma membrane • integral component of plasma membrane Biological process • regulation of calcium ion transport • adaptive immune response • immune system process • ion transport • calcium ion transmembrane transport • calcium ion transport • positive regulation of calcium ion transport • store-operated calcium entry • transport Sources:Amigo / QuickGO
Orthologs
Species	Human	Mouse
Entrez	84876	109305
Ensembl	n/a	ENSMUSG00000049686
UniProt	Q96D31	Q8BWG9
RefSeq (mRNA)	NM_032790	NM_175423
RefSeq (protein)	NP_116179	NP_780632
Location (UCSC)	n/a	Chr 5: 123.02 – 123.03 Mb
PubMed search

2MAK, 4EHQ

84876

109305

n/a

ENSMUSG00000049686

Q96D31

Q8BWG9

NM_032790

NM_175423

NP_116179

NP_780632

Calcium release-activated calcium channel protein 1 is a calcium selective ion channel that in humans is encoded by the ORAI1 gene. Orai channels play an important role in the activation of T-lymphocytes. The loss of function mutation of Orai1 causes severe combined immunodeficiency (SCID) in humans The mammalian orai family has two additional homologs, Orai2 and Orai3. Orai proteins share no homology with any other ion channel family of any other known proteins. They have 4 transmembrane domains and form hexamers.

Orai channels are activated upon the depletion of internal calcium stores, which is called the "store-operated" or the "capacitative" mechanism. They are molecular constituents of the "calcium release activated calcium currents" (ICRAC). Upon activation of phospholipase C by various cell surface receptors, inositol trisphosphate is formed that releases calcium from the endoplasmic reticulum. The decreased calcium concentration in the endoplasmic reticulum is sensed by the STIM1 protein. STIM1 clusters upon the depletion of the calcium stores and forms "puncta", and relocates near the plasma membrane, where it activates Orai1 via protein-protein interaction.

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