Ligand-gated anion channel that allows the movement of anions across cell membranes when activated by calcium (Ca2+) (PubMed:11904445, PubMed:12907679, PubMed:18179881, PubMed:18400985, PubMed:19853238, PubMed:21330666, PubMed:26200502, PubMed:26720466, PubMed:35789156). Allows the movement of chloride and hydrogencarbonate (PubMed:11904445, PubMed:12907679, PubMed:18179881, PubMed:18400985, PubMed:19853238, PubMed:21330666, PubMed:26200502, PubMed:26720466, PubMed:35789156). Found in a partially open conformation leading to significantly smaller chloride movement (PubMed:35789156). Upon F2R/PAR-1 activation, the sequestered calcium is released into the cytosol of astrocytes, leading to the (Ca2+)-dependent release of L- glutamate into the synaptic cleft that targets the neuronal postsynaptic GRIN2A/NMDAR receptor resulting in the synaptic plasticity regulation (By similarity). Upon activation of the norepinephrine- alpha-1 adrenergic receptor signaling pathway, transports as well D- serine than L-glutamate in a (Ca2+)-dependent manner, leading to activation of adjacent NMDAR receptors and therefore regulates the heterosynaptic long-term depression and metaplasticity during initial memory acquisition (By similarity). Releases the 4-aminobutanoate neurotransmitter in a (Ca2+)-dependent manner, and participates in its tonic release from cerebellar glial cells (By similarity). {ECO:0000250|UniProtKB:O88870, ECO:0000269|PubMed:11904445, ECO:0000269|PubMed:12907679, ECO:0000269|PubMed:18179881, ECO:0000269|PubMed:18400985, ECO:0000269|PubMed:19853238, ECO:0000269|PubMed:21330666, ECO:0000269|PubMed:26200502, ECO:0000269|PubMed:26720466, ECO:0000269|PubMed:35789156}. This is the function of Ensembl gene identifier ENSG00000167995 (BEST1, bestrophin 1).