This gene encodes a member of a family of membrane-associated phosphatidylinositol transfer domain-containing proteins. The calcium-binding protein has phosphatidylinositol (PI) transfer activity and interacts with the protein tyrosine kinase PTK2B (also known as PYK2). The protein is homologous to a Drosophila protein that is implicated in the visual transduction pathway in flies. Mutations in this gene result in autosomal dominant cone dystrophy. Multiple transcript variants encoding different isoforms have been found for this gene.[provided by RefSeq, Sep 2009].