UniProt ID: Q9DFS4 |
FUNCTION: Sterol-binding protein that mediates cholesterol transport from the endoplasmic reticulum to endosomes. Creates contact site between the endoplasmic reticulum and late endosomes: localizes to late endosome membranes and contacts the endoplasmic reticulum. Acts as a lipid transfer protein that redirects sterol to the endosome at the expense of the cell membrane and favors membrane formation inside endosomes. {ECO:0000250|UniProtKB:Q14849}. SUBUNIT: Homodimer. {ECO:0000250|UniProtKB:Q14849}. SUBCELLULAR LOCATION: Late endosome membrane {ECO:0000250|UniProtKB:Q14849}; Multi-pass membrane protein {ECO:0000255}. Note=Localizes to contact sites between the endoplasmic reticulum and late endosomes: associates with the endoplasmic reticulum membrane via interaction with VAPA and VAPB. {ECO:0000250|UniProtKB:Q14849}. DOMAIN: The START domain mediates lipid-transfer between membranes. It contains a hydrophobic cavity able to accommodate one lipid molecule, thereby serving as a 'hydrophobic bridge' across the aqueous gap between donor and acceptor organelle membranes. {ECO:0000250|UniProtKB:Q14849}. DOMAIN: The MENTAL domain anchors the protein in endosome membranes and exposes the START domain in the cytosol. {ECO:0000250|UniProtKB:Q14849}. SIMILARITY: Belongs to the STARD3 family. {ECO:0000305}. |
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