STARD3

This gene encodes a member of a subfamily of lipid trafficking proteins that are characterized by a C-terminal steroidogenic acute regulatory domain and an N-terminal metastatic lymph node 64 domain. The encoded protein localizes to the membranes of late endosomes and may be involved in exporting cholesterol. Alternate splicing results in multiple transcript variants

StAR-related lipid transfer (START) domain containing 3

Sterol-binding protein that mediates cholesterol transport from the endoplasmic reticulum to endosomes (PubMed:11053434, PubMed:15930133, PubMed:22514632, PubMed:28377464).
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 (PubMed:24105263, PubMed:28377464).
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 (PubMed:28377464).
May also mediate cholesterol transport between other membranes, such as mitochondria membrane or cell membrane (PubMed:12070139, PubMed:19965586).
However, such results need additional experimental evidences; probably mainly mediates cholesterol transport from the endoplasmic reticulum to endosomes (PubMed:28377464).
Does not activate transcriptional cholesterol sensing (PubMed:28377464).
Able to bind other lipids, such as lutein, a xanthophyll carotenoids that form the macular pigment of the retina (PubMed:21322544).

Biological Process cholesterol metabolic processManual Assertion Based On ExperimentTAS:ProtInc
Biological Process cholesterol transportManual Assertion Based On ExperimentIDA:UniProtKB
Biological Process lipid metabolic processManual Assertion Based On ExperimentTAS:ProtInc
Biological Process mitochondrial transportManual Assertion Based On ExperimentTAS:ProtInc
Biological Process progesterone biosynthetic processIEA:Ensembl
Biological Process steroid metabolic processManual Assertion Based On ExperimentTAS:ProtInc
Biological Process vesicle tethering to endoplasmic reticulumManual Assertion Based On ExperimentIDA:UniProtKB

Late endosome membrane
Localizes to contact sites between the endoplasmic reticulum and late endosomes: associates with the endoplasmic reticulum membrane via interaction with VAPA, VAPB or MOSPD2.

Cytoplasmic: 1-51
Helical: 52-72
Extracellular: 73-94
Helical: 95-115
Cytoplasmic: 116-120
Helical: 121-141
Extracellular: 142-148
Helical: 149-169
Cytoplasmic: 170-445