Cyclic nucleotide gated channels.

Recent studies have revealed that cyclic nucleotide gated channels have a variety of forms and functions. These channels are now thought to be heteromultimers of at least two kinds of subunits and to undergo functional modulation. Ion permeation involves at least two ion-binding sites, and recent work on the alpha subunit suggests that many structural regions are involved in the control of channel gating. The continued use of both molecular and physiological approaches promises to further our understanding of how these channels work and how they are involved in cellular function.