ANO2 Gene: Anoctamin 2 - Function, Mutations, and Disease Associations

ANO2 encodes anoctamin 2, a member of the anoctamin family of calcium-activated chloride channels (CaCCs). The protein functions as a homodimer and is activated by intracellular calcium, mediating chloride ion transport across the plasma membrane. ANO2 is highly expressed in olfactory sensory neurons, photoreceptors, and various epithelial tissues, where it plays critical roles in olfactory transduction, phototransduction, and fluid secretion. Mutations and altered expression of ANO2 have been implicated in neurological disorders and certain cancers.

Tissue Expression

Cell Line Expression

Hotspot Mutations

Mutation functional classification

• Calcium signaling pathway (KEGG: hsa04020)

• Olfactory transduction (KEGG: hsa04740)

• Phototransduction (KEGG: hsa04744)

Anoctamin 2 (ANO2) is a 1,003-amino acid transmembrane protein with eight transmembrane domains, forming a calcium-activated chloride channel. It functions as a homodimer, with each subunit contributing to the pore. The channel is activated by submicromolar intracellular calcium and mediates chloride efflux, regulating membrane excitability and fluid secretion. ANO2 is essential for olfactory signal amplification and photoreceptor synaptic transmission. Structural studies reveal a calcium-binding site in the N-terminal domain that triggers conformational changes leading to pore opening.