title: Autophagy-mediated catabolism of visual transduction proteins prevents retinal degeneration.
abstract: Autophagy is a lysosomal degradation pathway critical to preventing the accumulation of cytotoxic proteins. Deletion of the essential autophagy gene Atg5 from the rod photoreceptors of the retina (atg5Δrodmouse) results in the accumulation of the phototransduction protein transducin and the degeneration of these neurons. The purpose of this study is to test the hypothesis that autophagic degradation of visual transduction proteins prevents retinal degeneration. Targeted deletion of both Gnat1 (a gene encoding the α subunit of the heterotrimeric G-protein transducin) and Atg5 in the rod photoreceptors resulted in a significantly decreased rate of rod cell degeneration as compared to the atg5Δrodmouse retina, and considerable preservation of photoreceptors. Supporting this we used a novel technique to immunoprecipitate green fluorescent protein (GFP)-tagged autophagosomes from the retinas of the GFP-LC3 mice and demonstrated that the visual transduction proteins transducin and ARR/arrestin are associated with autophagosome-specific proteins. Altogether, this study shows that degradation of phototransduction proteins by autophagy is necessary to prevent retinal degeneration. In addition, we demonstrate a simple and easily reproducible immunoisolation technique for enrichment of autophagosomes from the GFP-LC3 mouse retina, providing a novel application to the study of autophagosome contents across different organs and specific cell types in vivo.
authors.affiliation: a Department of Ophthalmology and Visual Sciences , University of Michigan , Ann Arbor , MI , USA.
authors.forename: Jingyu
authors.initials: J
authors.lastname: Yao
authors.affiliation: a Department of Ophthalmology and Visual Sciences , University of Michigan , Ann Arbor , MI , USA.
authors.forename: Lin
authors.initials: L
authors.lastname: Jia
authors.affiliation: a Department of Ophthalmology and Visual Sciences , University of Michigan , Ann Arbor , MI , USA.
authors.forename: Kecia
authors.initials: K
authors.lastname: Feathers
authors.affiliation: a Department of Ophthalmology and Visual Sciences , University of Michigan , Ann Arbor , MI , USA.
authors.forename: Chengmao
authors.initials: C
authors.lastname: Lin
authors.affiliation: a Department of Ophthalmology and Visual Sciences , University of Michigan , Ann Arbor , MI , USA.
authors.forename: Naheed W
authors.initials: NW
authors.lastname: Khan
authors.affiliation: b Life Sciences Institute, University of Michigan , Ann Arbor , MI , USA.|c Department of Molecular , Cellular and Developmental Biology, University of Michigan , Ann Arbor , MI , USA.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Klionsky
authors.affiliation: d Department of Ophthalmology and Visual Sciences , Washington University School of Medicine , St. Louis , MO , USA.
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Ferguson
authors.affiliation: a Department of Ophthalmology and Visual Sciences , University of Michigan , Ann Arbor , MI , USA.
authors.forename: David N
authors.initials: DN
authors.lastname: Zacks
mesh_terms: D000818:Animals; D000071182:Autophagosomes / Q000378:metabolism; D001343:Autophagy; D000071187:Autophagy-Related Protein 5 / Q000378:metabolism; D002460:Cell Line; D003433:Crosses, Genetic; D005136:Eye Proteins / Q000378:metabolism*; D005260:Female; D044385:GTP-Binding Protein alpha Subunits / Q000172:deficiency / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000378:metabolism; D055537:Light Signal Transduction; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D059748:Proteolysis; D015203:Reproducibility of Results; D017949:Retinal Cone Photoreceptor Cells / Q000378:metabolism / Q000473:pathology; D012162:Retinal Degeneration / Q000378:metabolism* / Q000473:pathology*; D015293:Transducin / Q000172:deficiency / Q000378:metabolism; D014162:Transfection
chemical_list: C495773:Atg5 protein, mouse; D000071187:Autophagy-Related Protein 5; D005136:Eye Proteins; D044385:GTP-Binding Protein alpha Subunits; C488949:Gnat1 protein, mouse; D049452:Green Fluorescent Proteins; D015293:Transducin
keywords: autophagy; photoreceptor; retina; retinal degeneration; transducin