Transmembrane protein mainly expressed in brain astrocytes that may play a role in transport across the blood-brain and brain- cerebrospinal fluid barriers (PubMed:22328087). Regulates the response of astrocytes to hypo-osmosis by promoting calcium influx (PubMed:22328087). May function as regulatory protein of membrane protein complexes such as ion channels (Probable). . This is the function of MLC1 (modulator of VRAC current 1, ENSG00000100427).