Gating in CNGA1 channels
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- Mazzolini, M., Marchesi, A., Giorgetti, A. et al. Pflugers Arch - Eur J Physiol (2010) 459: 547. doi:10.1007/s00424-009-0751-2
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The aminoacid sequences of CNG and K+ channels share a significant sequence identity, and it has been suggested that these channels have a common ancestral 3D architecture. However, K+ and CNG channels have profoundly different physiological properties: indeed, K+ channels have a high ionic selectivity, their gating strongly depends on membrane voltage and when opened by a steady depolarizing voltage several K+ channels inactivate, whereas CNG channels have a low ion selectivity, their gating is poorly voltage dependent, and they do not desensitize in the presence of a steady concentration of cyclic nucleotides that cause their opening. The purpose of the present review is to summarize and recapitulate functional and structural differences between K+ and CNG channels with the aim to understand the gating mechanisms of CNG channels.