The muscle acetylcholine receptor is composed of five subunits: two alpha subunits and one beta, one gamma, and one delta subunit. This gene encodes the beta subunit of the acetylcholine receptor. The acetylcholine receptor changes conformation upon acetylcholine binding leading to the opening of an ion-conducting channel across the plasma membrane. Mutations in this gene are associated with slow-channel congenital myasthenic syndrome. [provided by RefSeq, Jul 2008]
Function:
After binding acetylcholine, the AChR responds by an extensive change in conformation that affects all subunits and leads to opening of an ion-conducting channel across the plasma membrane.
Subcellular Location:
Cell junction > synapse > postsynaptic cell membrane. Cell membrane.
DISEASE:
Defects in CHRNB1 are a cause of congenital myasthenic syndrome slow-channel type (SCCMS) [MIM:601462]. SCCMS is the most common congenital myasthenic syndrome. Congenital myasthenic syndromes are characterized by muscle weakness affecting the axial and limb muscles (with hypotonia in early-onset forms), the ocular muscles (leading to ptosis and ophthalmoplegia), and the facial and bulbar musculature (affecting sucking and swallowing, and leading to dysphonia). The symptoms fluctuate and worsen with physical effort. SCCMS is caused by kinetic abnormalities of the AChR, resulting in prolonged endplate currents and prolonged AChR channel opening episodes.
Defects in CHRNB1 are a cause of congenital myasthenic syndrome with acetylcholine receptor deficiency (ACHRDCMS) [MIM:608931]. ACHRDCMS is a post-synaptic congenital myasthenic syndrome. Mutations underlying AChR deficiency cause a 'loss of function' and show recessive inheritance.
Similarity:
Belongs to the ligand-gated ion channel (TC 1.A.9) family. Acetylcholine receptor (TC 1.A.9.1) subfamily. Beta-1/CHRNB1 sub-subfamily.
SWISS:
P11230
Gene ID:
1140
Database links:
Entrez Gene: 282179 Cow
Entrez Gene: 1140 Human
Entrez Gene: 11443 Mouse
Entrez Gene: 24261 Rat
GenBank: NP_000738.2 Human
Omim: 100710 Human
SwissProt: P04758 Cow
SwissProt: P11230 Human
SwissProt: P09690 Mouse
SwissProt: P25109 Rat
Unigene: 330386 Human
Unigene: 86425 Mouse
Unigene: 44611 Rat
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