Open AccessSnf1 AMPK positively regulates ER-phagy via expression control of Atg39 autophagy receptor in yeast ER stress response
Author(s) -
Tomoaki Mizuno,
Kei Muroi,
Kenji Irie
Publication year - 2020
Publication title -
plos genetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.587
H-Index - 233
eISSN - 1553-7404
pISSN - 1553-7390
DOI - 10.1371/journal.pgen.1009053
Subject(s) - autophagy , endoplasmic reticulum , microbiology and biotechnology , downregulation and upregulation , unfolded protein response , ampk , biology , protein kinase a , phosphorylation , kinase , nuclear export signal , biochemistry , gene , cytoplasm , cell nucleus , apoptosis
Autophagy is a fundamental process responsible for degradation and recycling of intracellular contents. In the budding yeast, non-selective macroautophagy and microautophagy of the endoplasmic reticulum (ER) are caused by ER stress, the circumstance where aberrant proteins accumulate in the ER. The more recent study showed that protein aggregation in the ER initiates ER-selective macroautophagy, referred to as ER-phagy; however, the mechanisms by which ER stress induces ER-phagy have not been fully elucidated. Here, we show that the expression levels of ATG39 , encoding an autophagy receptor specific for ER-phagy, are significantly increased under ER-stressed conditions. ATG39 upregulation in ER stress response is mediated by activation of its promoter, which is positively regulated by Snf1 AMP-activated protein kinase (AMPK) and negatively by Mig1 and Mig2 transcriptional repressors. In response to ER stress, Snf1 promotes nuclear export of Mig1 and Mig2. Our results suggest that during ER stress response, Snf1 mediates activation of the ATG39 promoter and consequently facilitates ER-phagy by negatively regulating Mig1 and Mig2.