StAR-related lipid transfer protein 4 (StarD4) contains a steroidogenic acute regulatory-related lipid transfer (START) domain, a lipid binding domain which appears in a wide range of proteins involved in several cellular functions []. StarD4 is an intracellular cholesterol transporter that plays an important role in the maintenance of cellular cholesterol homeostasis. It binds free cholesterol and increases cholesteryl ester formation []. It is also involved in translocation of 7-hydroperoxycholesterol to isolated mitochondria []. The expression of StarD4 can be sterol-repressed through the SREBP-2 pathway [].
