Lysosomes are compartments for the degradation of both endocytic and autophagic cargoes. The shape of lysosomes changes with cellular degradative demands; however, there is limited knowledge about the mechanisms or significance that underlies distinct lysosomal morphologies. Here, we found an extensive tubular autolysosomal network in Drosophila abdominal muscle remodeling during metamorphosis. 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 Syntaxin17 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.

溶酶体是内吞和自噬货物降解的区室。溶酶体的形状随细胞降解需求而变化；然而，对于不同溶酶体形态背后的机制或意义的了解有限。在这里，我们在果蝇变态过程中腹部肌肉重塑中发现了广泛的管状自溶酶体网络。管状网络短暂出现并表现出降解自噬货物的能力。管状自溶酶体网络由自噬 SNARE 蛋白 Syntaxin17 独特标记，其形成取决于自噬通量和降解功能，但 Atg12 和 Atg8 泛素样缀合系统除外。在ATG缺陷突变体中，溶酶体管化的效率与肌肉重塑的表型严重程度相关。管状网络的内腔在重塑肌的广阔区域内是连续且均匀的。总而言之，我们发现管状自溶酶体网络的动态扩张同步了发育调节的肌肉重塑所需的丰富的降解活动。