环核苷酸门控离子通道的结构、功能及活性调节

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Ca2+进入细胞内的主要通道之一.CNG离子通道的活性可被Ca2+ /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.

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

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 (A1 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 cells. Ca~ 2 influx through CNGs is important to increase the intracellular concentration of Ca~ 2 . The increased Ca~ 2 can induce a series 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.