Ceramidase expression facilitates membrane turnover and endocytosis of rhodopsin in photoreceptors
Acharya, Usha ; Mowen, Michael Beth ; Nagashima, Kunio ; Acharya, Jairaj K.
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Student Authors
Faculty Advisor
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UMass Chan Affiliations
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Keywords
Animals
Animals, Genetically Modified
Cell Membrane
Ceramidases
Darkness
Drosophila Proteins
Drosophila melanogaster
*Endocytosis
Eye Proteins
Half-Life
Ligands
Light
Mutation
Photoreceptor Cells, Invertebrate
Receptors, G-Protein-Coupled
Retinal Degeneration
Rhodopsin
Genetics and Genomics
Subject Area
Embargo Expiration Date
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Abstract
Transgenic expression of ceramidase suppresses retinal degeneration in Drosophila arrestin and phospholipase C mutants. Here, we show that expression of ceramidase facilitates the dissolution of incompletely formed and inappropriately located elements of rhabdomeric membranes in ninaE(I17) mutants lacking the G protein receptor Rh1 in R1-R6 photoreceptor cells. Ceramidase expression facilitates the endocytic turnover of Rh1. Although ceramidase expression aids the removal of internalized rhodopsin, it does not affect the turnover of Rh1 in photoreceptors maintained in dark, where Rh1 is not activated and thus has a slower turnover and a long half-life. Therefore, the phenotypic consequence of ceramidase expression in photoreceptors is caused by facilitation of endocytosis. This study provides mechanistic insight into the sphingolipid biosynthetic pathway-mediated modulation of endocytosis and suppression of retinal degeneration.
Source
Proc Natl Acad Sci U S A. 2004 Feb 17;101(7):1922-6. Epub 2004 Feb 9. Link to article on publisher's site