Odorant signal transduction is probably mediated by a G-protein coupled cascade using cAMP as second messenger. The olfactory channel can be shown to be activated by cyclic nucleotides which leads to a depolarization of olfactory sensory neurons. Heterotetramer composed of two subunits of CNGA2, one of CNGA4 and one of CNGB1b. The complex forms the cyclic nucleotide-gated (CNG) channel of olfactory sensory neurons (By similarity). The C-terminal coiled-coil domain mediates trimerization of CNGA subunits. Belongs to the cyclic nucleotide-gated cation channel (TC 1.A.1.5) family. CNGA2 subfamily. It is uncertain whether Met-1 or Met-2 is the initiator.