A Palmitoylation Switch Mechanism in the Regulation of the Visual Cycle
| Autor: | Linlong Xue, Wan Jin Jahng, Robert R. Rando, Pranab Maiti, Deviprasad R. Gollapalli |
|---|---|
| Rok vydání: | 2004 |
| Předmět: |
Rhodopsin
Tretinoin Plasma protein binding Biology Ligands General Biochemistry Genetics and Molecular Biology Cell Line Fatty Acids Monounsaturated Phosphatidylcholine-Sterol O-Acyltransferase Palmitoylation Animals Protein Isoforms Transferase Photoreceptor Cells Eye Proteins Vitamin A Vision Ocular Biochemistry Genetics and Molecular Biology(all) technology industry and agriculture Proteins Acyl carrier protein RPE65 Biochemistry Chaperone (protein) Retinaldehyde biology.protein Cattle lipids (amino acids peptides and proteins) Molecular Chaperones Protein Binding |
| Zdroj: | Cell. 117(6):761-771 |
| ISSN: | 0092-8674 |
| DOI: | 10.1016/j.cell.2004.05.016 |
| Popis: | RPE65 is essential for the biosynthesis of 11-cis-retinal, the chromophore of rhodopsin. Here, we show that the membrane-associated form (mRPE65) is triply palmitoylated and is a chaperone for all-trans-retinyl esters, allowing their entry into the visual cycle for processing into 11-cis-retinal. The soluble form of RPE65 (sRPE65) is not palmitoylated and is a chaperone for vitamin A, rather than all-trans-retinyl esters. Thus, the palmitoylation of RPE65 controls its ligand binding selectivity. The two chaperones are interconverted by lecithin retinol acyl transferase (LRAT) acting as a molecular switch. Here mRPE65 is a palmitoyl donor, revealing a new acyl carrier protein role for palmitoylated proteins. When chromophore synthesis is not required, mRPE65 is converted into sRPE65 by LRAT, and further chromophore synthesis is blocked. The studies reveal new roles for palmitoylated proteins as molecular switches and LRAT as a palmitoyl transferase whose role is to catalyze the mRPE65 to sRPE65 conversion. |
| Databáze: | OpenAIRE |
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