Pex3-anchored Atg36 tags peroxisomes for degradation in Saccharomyces cerevisiae.
Peroxisomes undergo rapid, selective autophagic degradation (pexophagy) when the metabolic pathways they contain are no longer required for cellular metabolism. Pex3 is central to the formation of peroxisomes and their segregation because it recruits factors specific for these functions. Here, we describe a novel Saccharomyces cerevisiae protein that interacts with Pex3 at the peroxisomal membrane. We name this protein Atg36 as its absence blocks pexophagy, and its overexpression induces pexophagy. We have isolated pex3 alleles blocked specifically in pexophagy that cannot recruit Atg36 to peroxisomes. Atg36 is recruited to mitochondria if Pex3 is redirected there, where it restores mitophagy in cells lacking the mitophagy receptor Atg32. Furthermore, Atg36 binds Atg8 and the adaptor Atg11 that links receptors for selective types of autophagy to the core autophagy machinery. Atg36 delivers peroxisomes to the preautophagosomal structure before being internalised into the vacuole with peroxisomes. We conclude that Pex3 recruits the pexophagy receptor Atg36. This reinforces the pivotal role played by Pex3 in coordinating the size of the peroxisome pool, and establishes its role in pexophagy in S. cerevisiae.
Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield, UK. e.hettema@sheffield.ac.uk
Alison M
AM
Motley
James M
JM
Nuttall
Ewald H
EH
Hettema
D001343:Autophagy / Q000502:physiology; D000071190:Autophagy-Related Protein 8 Family; D000071183:Autophagy-Related Proteins; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism; D000074401:Peroxins; D020675:Peroxisomes / Q000378:metabolism*; D011485:Protein Binding; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D014617:Vacuoles / Q000378:metabolism; D033921:Vesicular Transport Proteins / Q000378:metabolism
C523512:ATG36 protein, S cerevisiae; C113757:ATG8 protein, S cerevisiae; C502923:Atg11 protein, S cerevisiae; D000071190:Autophagy-Related Protein 8 Family; D000071183:Autophagy-Related Proteins; D008565:Membrane Proteins; D008869:Microtubule-Associated Proteins; C070895:PEX3 protein, S cerevisiae; D000074401:Peroxins; D029701:Saccharomyces cerevisiae Proteins; D033921:Vesicular Transport Proteins