Structural basis of properties, mechanisms, and channelopathy of cyclic nucleotide-gated channels

ABSTRACT

Recent years have seen an outpouring of atomic or near atomic resolution structures of cyclic nucleotide-gated (CNG) channels, captured in closed, transition, pre-open, partially open, and fully open states. These structures provide unprecedented molecular insights into the activation, assembly, architecture, regulation, and channelopathy of CNG channels, as well as mechanistic explanations for CNG channel biophysical and pharmacological properties. This article summarizes recent advances in CNG channel structural biology, describes key structural features and elements, and illuminates a detailed conformational landscape of activation by cyclic nucleotides. The review also correlates structures with findings and properties delineated in functional studies, including nonselective monovalent cation selectivity, Ca²⁺ permeation and block, block by L-cis-diltiazem, location of the activation gate, lack of voltage-dependent gating, and modulation by lipids and calmodulin. A perspective on future research is also offered.

KEYWORDS:

• CNG channel
• cryo-EM structure
• allosteric gating
• cGMP
• conformation landscape

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

Data sharing is not applicable to this article as no new data were created or analyzed in this study.

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/19336950.2023.2273165

Additional information

Funding

This work was supported by the National Institutes of Health [R01EY032880].