The function of Ensembl gene identifier ENSG00000138172 (CALHM2, calcium homeostasis modulator family member 2) is as follows. Pore-forming subunit of Ca(2+) homeostasis modulator channels. Mediates ATP release from astrocytes and ATP-induced Ca(2+) influx in microglia thus regulating neuronal ATP and Ca(2+) homeostasis, synaptic transmission and neuroinflammatory response. May form intercellular gap junctions. The gating mechanism remains unknown. {ECO:0000250|UniProtKB:Q8VEC4, ECO:0000269|PubMed:31776515, ECO:0000269|PubMed:32832629}.