Sarcoplasmic reticulum remodeling through autophagosome biogenesis during Drosophila metamorphosis
- 1Institute of Science Tokyo
Abstract
The sarcoplasmic reticulum (SR) is an elaborate membrane network and the primary intracellular Ca2+ store for muscle contraction. SR abundance, morphology, and spatial organization must be remodeled during muscle atrophy and hypertrophy, yet the mechanisms underlying this remodeling remain poorly understood. Autophagy has been implicated in SR homeostasis and may contribute to this process. We previously showed that a subset of Drosophila larval muscles remodels into adult dorsal internal oblique muscles through an autophagy-dependent process accompanied by extensive SR reorganization. Here, we show that autophagy is essential for maintaining SR abundance and architecture during muscle remodeling. Blocking autophagosome formation caused the accumulation of large aggregates of SR membranes, whereas blocking autophagosome-lysosome fusion led to the accumulation of autophagosomes with SR transmembrane proteins localized to their membranes. Moreover, disrupting LC3-interacting region (LIR)-dependent cargo recognition did not impair SR remodeling, arguing against a major contribution from selective autophagic degradation of the SR. Instead, our findings suggest that SR membrane components are incorporated into autophagosomal membranes during muscle remodeling. We propose that this membrane flow couples the removal of excess SR membrane to autophagosome biogenesis during atrophy, thereby facilitating large-scale SR reorganization during muscle remodeling.
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BibTeX
@misc{kasai2026sarcoplasmic,
title = {{Sarcoplasmic reticulum remodeling through autophagosome biogenesis during Drosophila metamorphosis}},
author = {Y. Kasai and S. Borthakur and S. Bennani and Y. Sakamaki and T. Murakawa and N. Fujita},
howpublished = {bioRxiv},
year = {2026},
month = oct,
doi = {10.64898/2026.10.01.755830},
url = {https://www.biorxiv.org/content/10.64898/2026.10.01.755830v1},
note = {CC BY-NC-ND},
}
RIS
TY - UNPB
TI - Sarcoplasmic reticulum remodeling through autophagosome biogenesis during Drosophila metamorphosis
AU - Y. Kasai
AU - S. Borthakur
AU - S. Bennani
AU - Y. Sakamaki
AU - T. Murakawa
AU - N. Fujita
PY - 2026
DA - 2026/10/01
PB - bioRxiv
DO - 10.64898/2026.10.01.755830
UR - https://www.biorxiv.org/content/10.64898/2026.10.01.755830v1
AB - The sarcoplasmic reticulum (SR) is an elaborate membrane network and the primary intracellular Ca2+ store for muscle contraction. SR abundance, morphology, and spatial organization must be remodeled during muscle atrophy and hypertrophy, yet the mechanisms underlying this remodeling remain poorly understood. Autophagy has been implicated in SR homeostasis and may contribute to this process. We previously showed that a subset of Drosophila larval muscles remodels into adult dorsal internal oblique muscles through an autophagy-dependent process accompanied by extensive SR reorganization. Here, we show that autophagy is essential for maintaining SR abundance and architecture during muscle remodeling. Blocking autophagosome formation caused the accumulation of large aggregates of SR membranes, whereas blocking autophagosome-lysosome fusion led to the accumulation of autophagosomes with SR transmembrane proteins localized to their membranes. Moreover, disrupting LC3-interacting region (LIR)-dependent cargo recognition did not impair SR remodeling, arguing against a major contribution from selective autophagic degradation of the SR. Instead, our findings suggest that SR membrane components are incorporated into autophagosomal membranes during muscle remodeling. We propose that this membrane flow couples the removal of excess SR membrane to autophagosome biogenesis during atrophy, thereby facilitating large-scale SR reorganization during muscle remodeling.
ER -