A reversible temperature block captures pre-lysosomal intermediates of starvation-induced ERphagy
- 1Institute for Research in Biomedicine
Abstract
The selective lysosomal turnover of endoplasmic reticulum (ER) portions, termed ERphagy, removes aged, excess or damaged ER domains. The intermediates forming between receptor activation and lysosomal delivery are short-lived and remain poorly resolved. Here we identify a reversible temperature block at 25{degree sign}C that arrests ERphagy before lysosomal delivery. At this temperature, nutrient restriction still drives focal accumulation of the endogenously Halo-tagged ERphagy receptor TEX264 (puncta formation), segregation of ER cargo, remodelling of the ER membrane, whereas delivery of this material to degradative endolysosomes is strongly reduced. Rewarming above 27{degrees} restores lysosomal delivery, showing that the accumulated eTEX264-Halo puncta correspond to pre-lysosomal intermediates of the ERphagy program. Their formation requires ULK1/2 activity, the ATG7-dependent conjugation machinery, ATG9A, ATG13 and FIP200, coupling receptor clustering to autophagosome biogenesis. Consistently, expansion microscopy and electron tomography reveal curved, cradle-like TEX264-positive ER domains containing ER cargo, co-localizing with autophagy markers and lying adjacent to p62-cargo condensates.
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BibTeX
@misc{molinari2026reversible,
title = {{A reversible temperature block captures pre-lysosomal intermediates of starvation-induced ERphagy}},
author = {M. Molinari and M. Fabbro and T. Solda and D. Morone and C. Galli and A. Raimondi},
howpublished = {bioRxiv},
year = {2026},
month = oct,
doi = {10.64898/2026.10.06.756943},
url = {https://www.biorxiv.org/content/10.64898/2026.10.06.756943v1},
note = {CC BY-NC-ND},
}
RIS
TY - UNPB
TI - A reversible temperature block captures pre-lysosomal intermediates of starvation-induced ERphagy
AU - M. Molinari
AU - M. Fabbro
AU - T. Solda
AU - D. Morone
AU - C. Galli
AU - A. Raimondi
PY - 2026
DA - 2026/10/06
PB - bioRxiv
DO - 10.64898/2026.10.06.756943
UR - https://www.biorxiv.org/content/10.64898/2026.10.06.756943v1
AB - The selective lysosomal turnover of endoplasmic reticulum (ER) portions, termed ERphagy, removes aged, excess or damaged ER domains. The intermediates forming between receptor activation and lysosomal delivery are short-lived and remain poorly resolved. Here we identify a reversible temperature block at 25{degree sign}C that arrests ERphagy before lysosomal delivery. At this temperature, nutrient restriction still drives focal accumulation of the endogenously Halo-tagged ERphagy receptor TEX264 (puncta formation), segregation of ER cargo, remodelling of the ER membrane, whereas delivery of this material to degradative endolysosomes is strongly reduced. Rewarming above 27{degrees} restores lysosomal delivery, showing that the accumulated eTEX264-Halo puncta correspond to pre-lysosomal intermediates of the ERphagy program. Their formation requires ULK1/2 activity, the ATG7-dependent conjugation machinery, ATG9A, ATG13 and FIP200, coupling receptor clustering to autophagosome biogenesis. Consistently, expansion microscopy and electron tomography reveal curved, cradle-like TEX264-positive ER domains containing ER cargo, co-localizing with autophagy markers and lying adjacent to p62-cargo condensates.
ER -