CHRNB3

The nicotinic acetylcholine receptors (nAChRs) are members of a superfamily of ligand-gated ion channels that mediate fast signal transmission at synapses. The nAChRs are (hetero)pentamers composed of homologous subunits. The subunits that make up the muscle and neuronal forms of nAChRs are encoded by separate genes and have different primary structure. There are several subtypes of neuronal nAChRs that vary based on which homologous subunits are arranged around the central channel. They are classified as alpha-subunits if, like muscle alpha-1 (MIM 100690), they have a pair of adjacent cysteines as part of the presumed acetylcholine binding site. Subunits lacking these cysteine residues are classified as beta-subunits (Groot Kormelink and Luyten, 1997 [PubMed 9009220]). Elliott et al. (1996) [PubMed 8906617] stated that the proposed structure for each subunit is a conserved N-terminal extracellular domain followed by 3 conserved transmembrane domains, a variable cytoplasmic loop, a fourth conserved transmembrane domain, and a short C-terminal extracellular region.[supplied by OMIM, Apr 2010]

烟碱型乙酰胆碱受体（nAChRs）属于配体门控离子通道超家族，介导突触处的快速信号传递。nAChRs是由同源亚基组成的（异源）五聚体。构成肌肉和神经元型nAChRs的亚基由不同的基因编码，并具有不同的初级结构。根据围绕中央通道排列的同源亚基的不同，存在多种神经元nAChRs亚型。如果它们像肌肉α-1（MIM 100690）一样，在其假定的乙酰胆碱结合位点具有相邻的两个半胱氨酸，则被归类为α亚基。缺乏这些半胱氨酸残基的亚基被归类为β亚基（Groot Kormelink和Luyten，1997 [PubMed 9009220]）。Elliott等人（1996）[PubMed 8906617]提出，每个亚基的结构模式为一个保守的N端细胞外结构域，随后是3个保守的跨膜结构域，一个可变的细胞内环，第四个保守的跨膜结构域，以及一个短的C端细胞外区域。[由OMIM提供，2010年4月]