STARD3 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 via interaction with VAPA and VAPB. 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. May also mediate cholesterol transport between other membranes, such as mitochondria membrane or cell membrane. However, such results need additional experimental evidences; probably mainly mediates cholesterol transport from the endoplasmic reticulum to endosomes. Does not activate transcriptional cholesterol sensing. Able to bind other lipids, such as lutein, a xanthophyll carotenoids that form the macular pigment of the retina. Belongs to the STARD3 family. Expressed in retina. 3 alternatively spliced human isoforms have been reported. Note: This description may include information from UniProtKB.
Protein type: Membrane protein, integral; Membrane protein, multi-pass
Chromosomal Location of human Ortholog: 17q12
Cellular Component:  cytoplasm; cytosol; endoplasmic reticulum membrane; endoplasmic reticulum-endosome membrane contact site; endosome; intracellular membrane-bounded organelle; late endosome membrane; mitochondrion; nucleoplasm; organelle membrane contact site
Molecular Function:  cholesterol binding; cholesterol transfer activity; protein binding; protein homodimerization activity
Biological Process:  cholesterol metabolic process; cholesterol transport; intermembrane lipid transfer; lipid metabolic process; mitochondrial transport; progesterone biosynthetic process; steroid metabolic process; vesicle tethering to endoplasmic reticulum
Reference #:  Q14849 (UniProtKB)
Alt. Names/Synonyms: CAB1; es64; FLJ41370; Metastatic lymph node gene 64 protein; metastatic lymph node protein 64; MLN 64; MLN64; Protein CAB1; StAR related lipid transfer domain containing 3; StAR-related lipid transfer (START) domain containing 3; StAR-related lipid transfer protein 3; STAR3; STARD3; START domain-containing protein 3; steroidogenic acute regulatory protein related
Gene Symbols: STARD3
Molecular weight: 50,502 Da
Basal Isoelectric point: 8.53  Predict pI for various phosphorylation states
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Protein Structure Not Found.

Cross-references to other databases:  AlphaFold  |  STRING  |  cBioPortal  |  Wikipedia  |  neXtProt  |  Protein Atlas  |  BioGPS  |  Pfam  |  RCSB PDB  |  Phospho3D  |  Phospho.ELM  |  NetworKIN  |  GeneCards  |  UniProtKB  |  Entrez-Gene  |  GenPept  |  Ensembl Gene  |  Ensembl Protein