Module 3: Figure cyclic nucleotide-gated channels
The cyclic nucleotide-gated channel (CNGC) family.
There are six members of the cyclic nucleotide-gated channel (CNGC) family: four α subunits, which form the pores, and two β subunits that have more of a modulatory role. They all have six transmembrane (TM) domains with both the N- and C-termini facing the cytoplasm. A pore region lies between TM5 and TM6. The examples shown at the bottom illustrate how the functional channels found in different sensory cells are heterotetramers made up of different subunit combinations. The C-terminal domain contains the cyclic nucleotide-binding domain (CNBD), whereas the N-terminal region of the CNGB1 subunit contains a binding site for calmodulin (CaM).