Cooper E, Couturier S, Ballivet M
Department of Physiology, McGill University, Montréal, Québec, Canada.
Nature. 1991 Mar 21;350(6315):235-8. doi: 10.1038/350235a0.
Neuronal nicotinic acetylcholine receptors are members of a gene family of ligand-gated transmitter receptors that includes muscle nicotinic receptors, GABAA receptors and glycine receptors. Several lines of evidence indicate that neuronal nicotinic receptors can be made up of only two subunits, an alpha (alpha) subunit which binds ligand, and a non-alpha (n alpha) or beta (beta) subunit. The stoichiometry of each subunit in the functional receptor has been difficult to assess, however. Estimates of the molecular weight of neuronal nicotonic receptor macromolecules suggest that these receptors contain at least four subunits but probably not more than five. We have examined the subunit stoichiometry of the chick neuronal alpha 4/n alpha 1 receptor by first using site-directed mutagenesis to create subunits that confer different single channel properties on the receptor. Co-injection with wild-type and mutant subunits led to the appearance of receptors with wild-type, mutant and hybrid conductances. From the number of hybrid conductances, we could deduce the number of each subunit in the functional receptor.
神经元烟碱型乙酰胆碱受体是配体门控递质受体基因家族的成员，该家族包括肌肉型烟碱受体、GABAA受体和甘氨酸受体。多条证据表明，神经元烟碱型受体可能仅由两个亚基组成，一个结合配体的α亚基和一个非α（nα）或β亚基。然而，功能受体中每个亚基的化学计量比一直难以评估。对神经元烟碱型受体大分子分子量的估计表明，这些受体至少包含四个亚基，但可能不超过五个。我们通过首先使用定点诱变来创建赋予受体不同单通道特性的亚基，研究了鸡神经元α4/nα1受体的亚基化学计量比。野生型和突变型亚基的共注射导致出现具有野生型、突变型和混合电导的受体。根据混合电导的数量，我们可以推断出功能受体中每个亚基的数量。
