Lipid-binding START domain of mammalian STARD2 and related proteins
This subgroup includes the steroidogenic acute regulatory protein (StAR)-related lipid transfer (START) domains of STARD2 (also known as phosphatidylcholine transfer protein/PC-TP) and related proteins. It belongs to the START domain family, and in turn to the SRPBCC (START/RHO_alpha_C/PITP/Bet_v1/CoxG/CalC) domain superfamily of proteins that bind hydrophobic ligands. SRPBCC domains have a deep hydrophobic ligand-binding pocket. STARD2 is a cytosolic phosphatidycholine (PtdCho) transfer protein, which traffics PtdCho, the most common class of phospholipids in eukaryotes, between membranes. It represents a minimal START domain structure. STARD2 plays roles in hepatic cholesterol metabolism, in the development of atherosclerosis, and may have a mitochondrial function.