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GRAMD1B
Cholesterol transporter that mediates non-vesicular transport of cholesterol from the plasma membrane (PM) to the endoplasmic reticulum (ER). Contains unique domains for binding cholesterol and the PM, thereby serving as a molecular bridge for the transfer of cholesterol from the PM to the ER. Plays a crucial role in cholesterol homeostasis in the adrenal gland and has the unique ability to localize to the PM based on the level of membrane cholesterol. In lipid-poor conditions localizes to the ER membrane and in response to excess cholesterol in the PM is recruited to the endoplasmic reticulum-plasma membrane contact sites (EPCS) which is mediated by the GRAM domain. At the EPCS, the sterol-binding VASt/ASTER domain binds to the cholesterol in the PM and facilitates its transfer from the PM to ER. 4 alternatively spliced human isoforms have been reported. Note: This description may include information from UniProtKB.
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| Protein type: Membrane protein, integral |
| Chromosomal Location of human Ortholog: 11q24.1 |
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Cellular Component:
endoplasmic reticulum membrane; endoplasmic reticulum-plasma membrane contact site; plasma membrane
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Molecular Function:
cholesterol binding; cholesterol transfer activity; phosphatidic acid binding; phosphatidylserine binding
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Biological Process:
cellular response to cholesterol; cholesterol homeostasis; intermembrane lipid transfer; intracellular sterol transport
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Reference #:
Q3KR37
(UniProtKB)
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Alt. Names/Synonyms: ASTRB; GRAM domain containing 1B; GRAM domain-containing protein 1B; GRAMD1B; GRM1B; KIAA1201; LINC01059; long intergenic non-protein coding RNA 1059; MGC125622; MGC125623; MGC125625; Protein Aster-B
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Gene Symbols: GRAMD1B
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Molecular weight:
85,400 Da
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Basal Isoelectric point:
5.84
Predict pI for various phosphorylation states
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