The function of Ensembl gene identifier ENSG00000185933 (CALHM1, calcium homeostasis modulator 1) is as follows. Pore-forming subunit of gustatory voltage-gated ion channels required for sensory perception of sweet, bitter and umami tastes (By similarity). With CALHM3 forms a fast-activating voltage-gated ATP- release channel in type II taste bud cells, ATP acting as a neurotransmitter to activate afferent neural gustatory pathways (By similarity) (PubMed:23467090). Acts both as a voltage-gated and calcium-activated ion channel: mediates neuronal excitability in response to membrane depolarization and low extracellular Ca(2+) concentration (PubMed:22711817, PubMed:23300080). Has poor ion selectivity and forms a wide pore (around 14 Angstroms) that mediates permeation of small ions including Ca(2+), Na(+), K(+) and Cl(-), as well as larger ions such as ATP(4-) (PubMed:22711817, PubMed:23300080, PubMed:32832629, PubMed:37380652). Mediates Ca(2+) influx and downstream activation of the ERK1 and ERK2 cascade in neurons (PubMed:23345406). Triggers endoplasmic reticulum stress by reducing the Ca(2+) content of the endoplasmic reticulum (PubMed:21574960). May indirectly control amyloid precursor protein (APP) proteolysis and aggregated amyloid-beta (Abeta) peptides levels in a Ca(2+)-dependent manner (PubMed:18585350). {ECO:0000250|UniProtKB:D3Z291, ECO:0000269|PubMed:18585350, ECO:0000269|PubMed:21574960, ECO:0000269|PubMed:22711817, ECO:0000269|PubMed:23300080, ECO:0000269|PubMed:23345406, ECO:0000269|PubMed:23467090, ECO:0000269|PubMed:32832629, ECO:0000269|PubMed:37380652}.