This gene encodes a member of a family of transmembrane proteins that are involved in the transport of small molecules. The encoded protein participates in the vesicular uptake, storage, and secretion of adenoside triphosphate (ATP) and other nucleotides. A mutation in this gene was found in individuals with autosomal dominant disseminated superficial actinic porokeratosis-8. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Nov 2014].