Calcium homeostasis modulator protein 1 (CALHM1)

Specifically within type II taste bud cells, where it plays a central role in sweet, bitter and umami taste perception by inducing ATP release in the cell, ATP acting as a neurotransmitter to activate afferent nerve wracking pathways. Acts both as a voltage-gated and calcium-activated ion channel: mediates neuronal excitability in response to changes in extracellular Ca(2+) concentration.

Has poor ion selectivity and creates a wide pore (around 14 Angstroms) which mediates permeation of Ca(2+), Na(+) and K(+), in addition to permeation of monovalent anions. Acts as an activator of the ERK1 and ERK2 cascade.