Changes in endolysosomal organization define a pre-degenerative state in the crumbs mutant Drosophila retina

• Published in: PloS one 2019-12, Vol.14 (12), p.e0220220-e0220220
• Main Authors: Kraut, Rachel S, Knust, Elisabeth
• Format: Article
• Language: English
• Subjects: ADP-Ribosylation Factors - genetics; ADP-Ribosylation Factors - metabolism; Animals; Autophagy; Biology; Biology and Life Sciences; Biosynthesis; Cell Polarity - genetics; Compartments; Crumbs protein; Degeneration; Disease; Drosophila; Drosophila melanogaster - genetics; Drosophila Proteins - genetics; Drosophila Proteins - metabolism; Endosomes - metabolism; Eye Proteins - genetics; Genetic aspects; Genetics; Homeostasis; Insects; Light; Medicine and Health Sciences; Membrane Proteins - genetics; Membrane Proteins - metabolism; Membranes; Morphology; Mutants; Mutation; Nervous system; Neurodegeneration; Neurophysiology; Neurosciences; Oxidative stress; Photoreceptor Cells, Invertebrate - metabolism; Photoreceptors; Physical Sciences; Polarity; Protein Transport - genetics; rab GTP-Binding Proteins - genetics; rab GTP-Binding Proteins - metabolism; Research and Analysis Methods; Retina; Retina - metabolism; Retinal degeneration; Retinal Degeneration - genetics; Retinal Degeneration - prevention & control; Signal transduction; Social Sciences; Trends
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0220220

Mutations in the epithelial polarity gene crumbs (crb) lead to retinal degeneration in Drosophila and in humans. The overall morphology of the retina and its deterioration in Drosophila crb mutants has been well-characterized, but the cell biological origin of the degeneration is not well understood. Degenerative conditions in the retina and elsewhere in the nervous system often involve defects in degradative intracellular trafficking pathways. So far, however, effects of crb on the endolysosomal system, or on the spatial organization of these compartments in photoreceptor cells have not been described. We therefore asked whether photoreceptors in crb mutants exhibit alterations in endolysosomal compartments under pre-degenerative conditions, where the retina is still morphologically intact. Data presented here show that, already well before the onset of degeneration, Arl8, Rab7, and Atg8-carrying endolysosomal and autophagosomal compartments undergo changes in morphology and positioning with respect to each other in crb mutant retinas. We propose that these changes may be early signs of the degeneration-prone condition in crb retinas.