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Function of the SNARE Ykt6 on autophagosomes requires the Dsl1 complex and the Atg1 kinase complex
Author(s) -
Gao Jieqiong,
Kurre Rainer,
Rose Jaqueline,
Walter Stefan,
Fröhlich Florian,
Piehler Jacob,
Reggiori Fulvio,
Ungermann Christian
Publication year - 2020
Publication title -
embo reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.584
H-Index - 184
eISSN - 1469-3178
pISSN - 1469-221X
DOI - 10.15252/embr.202050733
Subject(s) - microbiology and biotechnology , vacuole , biology , endoplasmic reticulum , phosphorylation , guanine nucleotide exchange factor , vacuolar protein sorting , autophagy , gtpase , cytoplasm , biochemistry , apoptosis
The mechanism and regulation of fusion between autophagosomes and lysosomes/vacuoles are still only partially understood in both yeast and mammals. In yeast, this fusion step requires SNARE proteins, the homotypic vacuole fusion and protein sorting ( HOPS ) tethering complex, the RAB 7 GTP ase Ypt7, and its guanine nucleotide exchange factor ( GEF ) Mon1‐Ccz1. We and others recently identified Ykt6 as the autophagosomal SNARE protein. However, it has not been resolved when and how lipid‐anchored Ykt6 is recruited onto autophagosomes. Here, we show that Ykt6 is recruited at an early stage of the formation of these carriers through a mechanism that depends on endoplasmic reticulum ( ER )‐resident Dsl1 complex and COPII ‐coated vesicles. Importantly, Ykt6 activity on autophagosomes is regulated by the Atg1 kinase complex, which inhibits Ykt6 through direct phosphorylation. Thus, our findings indicate that the Ykt6 pool on autophagosomal membranes is kept inactive by Atg1 phosphorylation, and once an autophagosome is ready to fuse with vacuole, Ykt6 dephosphorylation allows its engagement in the fusion event.