Synonyms:ORP10, OSBP9 Background:Probable lipid transporter involved in lipid countertransport between the endoplasmic reticulum and the plasma membrane. Its ability to bind phosphatidylserine, suggests that it specifically exchanges phosphatidylserine with phosphatidylinositol 4-phosphate(PI4P), delivering phosphatidylserine to the plasma membrane in exchange for PI4P(PubMed:23934110)(Probable). Plays a role in negative regulation of lipid biosynthesis(PubMed:19554302). Negatively regulates APOB secretion from hepatocytes(PubMed:19554302, PubMed:22906437). Binds cholesterol and acidic phospholipids(PubMed:22906437). Also binds 25-hydroxycholesterol(PubMed:17428193). Binds phosphatidylserine(PubMed:23934110).