Neuronal acetylcholine receptor subunit alpha-5, also known as nAChRα5, is a protein that in humans is encoded by the CHRNA5 gene. The protein encoded by this gene is a subunit of certain nicotinic acetylcholine receptors (nAchR). Function Nicotinic acetylcholine receptors (nAChRs), such as CHRNA5, are members of a superfamily of ligand-gated ion channels that mediate fast signal transmission at synapses. The nAChRs are thought to be (hetero)pentamers composed of homologous subunits. CHRNA5 is a candidate gene for predisposition to nicotine dependence and to lung cancer risk. Polymorphisms in the CHRNA5 promoter are functionally associated with CHRNA5 transcript levels in lung tissue. Interactive pathway map See also Nicotinic acetylcholine receptor References Further reading External links Ion channels Nicotinic acetylcholine receptors