| Structural highlights
Function
OSBL1_HUMAN Binds phospholipids; exhibits strong binding to phosphatidic acid and weak binding to phosphatidylinositol 3-phosphate (By similarity). Stabilizes GTP-bound RAB7A on late endosomes/lysosomes and alters functional properties of late endocytic compartments via its interaction with RAB7A (PubMed:16176980). Binds 25-hydroxycholesterol and cholesterol (PubMed:17428193).[1] [2]
Publication Abstract from PubMed
Phosphatidylinositol phosphates (PIPs) and cholesterol are known to regulate the function of late endosomes and lysosomes (LELs), and ORP1L specifically localizes to LELs. Here, we show in vitro that ORP1 is a PI(4,5)P2- or PI(3,4)P2-dependent cholesterol transporter, but cannot transport any PIPs. In cells, both ORP1L and PI(3,4)P2 are required for the efficient removal of cholesterol from LELs. Structures of the lipid-binding domain of ORP1 (ORP1-ORD) in complex with cholesterol or PI(4,5)P2 display open conformations essential for ORP function. PI(4,5)P2/PI(3,4)P2 can facilitate ORP1-mediated cholesterol transport by promoting membrane targeting and cholesterol extraction. Thus, our work unveils a distinct mechanism by which PIPs may allosterically enhance OSBP/ORPs-mediated transport of major lipid species such as cholesterol.
Allosteric enhancement of ORP1-mediated cholesterol transport by PI(4,5)P2/PI(3,4)P2.,Dong J, Du X, Wang H, Wang J, Lu C, Chen X, Zhu Z, Luo Z, Yu L, Brown AJ, Yang H, Wu JW Nat Commun. 2019 Feb 19;10(1):829. doi: 10.1038/s41467-019-08791-0. PMID:30783101[3]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Johansson M, Lehto M, Tanhuanpaa K, Cover TL, Olkkonen VM. The oxysterol-binding protein homologue ORP1L interacts with Rab7 and alters functional properties of late endocytic compartments. Mol Biol Cell. 2005 Dec;16(12):5480-92. doi: 10.1091/mbc.e05-03-0189. Epub 2005, Sep 21. PMID:16176980 doi:http://dx.doi.org/10.1091/mbc.e05-03-0189
- ↑ Suchanek M, Hynynen R, Wohlfahrt G, Lehto M, Johansson M, Saarinen H, Radzikowska A, Thiele C, Olkkonen VM. The mammalian oxysterol-binding protein-related proteins (ORPs) bind 25-hydroxycholesterol in an evolutionarily conserved pocket. Biochem J. 2007 Aug 1;405(3):473-80. PMID:17428193 doi:http://dx.doi.org/10.1042/BJ20070176
- ↑ Dong J, Du X, Wang H, Wang J, Lu C, Chen X, Zhu Z, Luo Z, Yu L, Brown AJ, Yang H, Wu JW. Allosteric enhancement of ORP1-mediated cholesterol transport by PI(4,5)P2/PI(3,4)P2. Nat Commun. 2019 Feb 19;10(1):829. doi: 10.1038/s41467-019-08791-0. PMID:30783101 doi:http://dx.doi.org/10.1038/s41467-019-08791-0
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