Translocon component Sec62 acts in endoplasmic reticulum turnover during stress recovery

F Fumagalli, J Noack, TJ Bergmann, E Cebollero… - Nature cell …, 2016 - nature.com
F Fumagalli, J Noack, TJ Bergmann, E Cebollero, GB Pisoni, E Fasana, I Fregno, C Galli…
Nature cell biology, 2016nature.com
The endoplasmic reticulum (ER) is a site of protein biogenesis in eukaryotic cells. Perturbing
ER homeostasis activates stress programs collectively called the unfolded protein response
(UPR). The UPR enhances production of ER-resident chaperones and enzymes to reduce
the burden of misfolded proteins. On resolution of ER stress, ill-defined, selective autophagic
programs remove excess ER components. Here we identify Sec62, a constituent of the
translocon complex regulating protein import in the mammalian ER, as an ER-resident …
Abstract
The endoplasmic reticulum (ER) is a site of protein biogenesis in eukaryotic cells. Perturbing ER homeostasis activates stress programs collectively called the unfolded protein response (UPR). The UPR enhances production of ER-resident chaperones and enzymes to reduce the burden of misfolded proteins. On resolution of ER stress, ill-defined, selective autophagic programs remove excess ER components. Here we identify Sec62, a constituent of the translocon complex regulating protein import in the mammalian ER, as an ER-resident autophagy receptor. Sec62 intervenes during recovery from ER stress to selectively deliver ER components to the autolysosomal system for clearance in a series of events that we name recovER-phagy. Sec62 contains a conserved LC3-interacting region in the C-terminal cytosolic domain that is required for its function in recovER-phagy, but is dispensable for its function in the protein translocation machinery. Our results identify Sec62 as a critical molecular component in maintenance and recovery of ER homeostasis.
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