@article {Murakawa2020.04.15.043075, author = {Tadayoshi Murakawa and Amy A. Kiger and Yuriko Sakamaki and Mitsunori Fukuda and Naonobu Fujita}, title = {An Autophagy-Dependent Tubular Lysosomal Network Synchronizes Degradative Activity Required for Muscle Remodeling}, elocation-id = {2020.04.15.043075}, year = {2020}, doi = {10.1101/2020.04.15.043075}, publisher = {Cold Spring Harbor Laboratory}, abstract = {Previously, we reported that autophagy is critical for Drosophila muscle remodeling during metamorphosis (Fujita et al., 2017). However, little is known about how lysosomes meet increased degradative demand upon cellular remodeling. Here, we found an extensive tubular autolysosomal network in remodeling muscle. The tubular network transiently appeared and exhibited the capacity to degrade autophagic cargoes. The tubular autolysosomal network was uniquely marked by the autophagic SNARE protein, Syntaxin 17, and its formation depended on both autophagic flux and degradative function, with the exception of the Atg12 and Atg8 ubiquitin-like conjugation systems. Among ATG-deficient mutants, the efficiency of lysosomal tubulation correlated with the phenotypic severity in muscle remodeling. The lumen of the tubular network was continuous and homogeneous across a broad region of the remodeling muscle. Altogether, we revealed that the dynamic expansion of a tubular autolysosomal network synchronizes the abundant degradative activity required for developmentally regulated muscle remodeling.Impact Statement Analysis of developmentally-regulated Drosophila muscle remodeling revealed autophagy-dependent formation of an extensive, Syntaxin 17-marked, tubular network that synchronizes the abundant degradative activity across a broad region of the remodeling muscleCompeting Interest StatementALRautophagic lysosome reformationAPFafter puparium formationATGautophagy-relatedCp1cysteine protease 1DIOMdorsal internal oblique muscleDQdye quenchedFRAPfluorescence recovery after photobleachingmTORmechanistic target of rapamycinSNAREsoluble NSF attachment protein receptorStx17Syntaxin17tALtubular autolysosomeTEMtransmission electron microscopyV-ATPasevacuolar H+ ATPase3ILthird instar larvae.}, URL = {https://www.biorxiv.org/content/early/2020/04/16/2020.04.15.043075}, eprint = {https://www.biorxiv.org/content/early/2020/04/16/2020.04.15.043075.full.pdf}, journal = {bioRxiv} }