Opsin Is a Phospholipid Flippase
| Autor: | Indu Menon, Thomas Huber, Sumana Sanyal, Sourabh Banerjee, Sam Canis, John Hwa, Thomas P. Sakmar, Patrick Barré, J. David Warren, Anant K. Menon |
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| Rok vydání: | 2011 |
| Předmět: |
Opsin
Phospholipid Biology Article General Biochemistry Genetics and Molecular Biology chemistry.chemical_compound Adenosine Triphosphate Lipid translocation Animals Humans Phospholipids Opsins Agricultural and Biological Sciences(all) Biochemistry Genetics and Molecular Biology(all) Endoplasmic reticulum Vesicle Membrane Proteins Biological membrane Flippase Cell biology HEK293 Cells Gene Expression Regulation chemistry Membrane protein Cattle lipids (amino acids peptides and proteins) General Agricultural and Biological Sciences Photoreceptor Cells Vertebrate |
| Zdroj: | Current Biology. 21(2):149-153 |
| ISSN: | 0960-9822 |
| DOI: | 10.1016/j.cub.2010.12.031 |
| Popis: | SummaryPolar lipids must flip-flop rapidly across biological membranes to sustain cellular life [1, 2], but flipping is energetically costly [3] and its intrinsic rate is low. To overcome this problem, cells have membrane proteins that function as lipid transporters (flippases) to accelerate flipping to a physiologically relevant rate. Flippases that operate at the plasma membrane of eukaryotes, coupling ATP hydrolysis to unidirectional lipid flipping, have been defined at a molecular level [2]. On the other hand, ATP-independent bidirectional flippases that translocate lipids in biogenic compartments, e.g., the endoplasmic reticulum, and specialized membranes, e.g., photoreceptor discs [4, 5], have not been identified even though their activity has been recognized for more than 30 years [1]. Here, we demonstrate that opsin is the ATP-independent phospholipid flippase of photoreceptor discs. We show that reconstitution of opsin into large unilamellar vesicles promotes rapid (τ < 10 s) flipping of phospholipid probes across the vesicle membrane. This is the first molecular identification of an ATP-independent phospholipid flippase in any system. It reveals an unexpected activity for opsin and, in conjunction with recently available structural information on this G protein-coupled receptor [6, 7], significantly advances our understanding of the mechanism of ATP-independent lipid flip-flop. |
| Databáze: | OpenAIRE |
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