环核苷酸门控离子通道的结构、功能及活性调节

Molecular Structures,Physiological Roles and Regulatory Mechanisms of Cyclic Nucleotide-gated Ion Channels

环核苷酸门控离子通道（cyclic nucleotide-gated ion channels,CNG）是非选择性的阳离子通道,直接被环核苷酸活化.6个不同基因编码CNG离子通道蛋白,4个A亚单元（A1～A4）和2个B亚单元（B1,B3）.CNG离子通道是由2个或3个不同的亚单元组成的异四聚体复合物,是Ca^2＋进入细胞内的主要通道之一.CNG离子通道的活性可被Ca^2＋/CaM及磷酸化/去磷酸化作用所调节,从而改变细胞内钙离子浓度,触发一系列生理效应.近年来CNG离子通道的研究进展神速,成为生命科学的一个热点领域.本文对CNG离子通道的结构、功能及活性调节机制进行了综述.

Cyclic nucleotide-gated ion channels （CNGs） are nonselective cation channels and opened by the direct binding of cyclic nucleotides, cyclic GMP and cyclic AMP. Six different genes encode CNG proteins, four A subunits （AI to A4） and two B subunits. CNGs are heterotetrameric complexes consisting of two or three different types of subunits. CNGs are one of main entrances of Ca^2＋ influxion into ceils. Ca^2＋ influx through a series CNGs is important to increase the intracellular concentration of Ca^2＋ . The increased Ca^2＋ can induce of physiological processes. The activity of CNGs can be regulated by Ca^2＋/Ca^2＋ -binding proteins （CaM） and phosphorylation/dephosphorylation. Recently, a huge amount of researches on CNGs appeared in the literature, this article reviewed the molecular structures, physiological roles and regulatory mechanisms of CNGs.