title: Formation of the approximately 350-kDa Apg12-Apg5.Apg16 multimeric complex, mediated by Apg16 oligomerization, is essential for autophagy in yeast.
abstract: Autophagy, responsible for the delivery of cytoplasmic components to the lysosome/vacuole for degradation, is the major degradative pathway in eukaryotic cells. This process requires a ubiquitin-like protein conjugation system, in which Apg12 is covalently bound to Apg5. In the yeast Saccharomyces cerevisiae, the Apg12-Apg5 conjugate further interacts with a small coiled-coil protein, Apg16. The Apg12-Apg5 and Apg16 are localized in the cytosol and pre-autophagosomal structures and play an essential role in autophagosome formation. Here we show that the Apg12-Apg5 conjugate and Apg16 form a approximately 350-kDa complex in the cytosol. Because Apg16 was suggested to form a homo-oligomer, we generated an in vivo system that allowed us to control the oligomerization state of Apg16. With this system, we demonstrated that formation of the approximately 350-kDa complex and autophagic activity depended on the oligomerization state of Apg16. These results suggest that the Apg12-Apg5 conjugate and Apg16 form a multimeric complex mediated by the Apg16 homo-oligomer, and formation of the approximately 350-kDa complex is required for autophagy in yeast.
authors.affiliation: Department of Cell Biology, National Institute for Basic Biology, 38 Nishigonaka, Myodaiji, Okazaki 444-8585, Japan.
authors.forename: Akiko
authors.initials: A
authors.lastname: Kuma
authors.forename: Noboru
authors.initials: N
authors.lastname: Mizushima
authors.forename: Naotada
authors.initials: N
authors.lastname: Ishihara
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Ohsumi
mesh_terms: D001343:Autophagy; D000071192:Autophagy-Related Protein 12; D000071187:Autophagy-Related Protein 5; D000071183:Autophagy-Related Proteins; D001483:Base Sequence; D002352:Carrier Proteins / Q000378:metabolism*; D002850:Chromatography, Gel; D003600:Cytosol / Q000378:metabolism; D017931:DNA Primers; D008565:Membrane Proteins / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*; D014157:Transcription Factors; D044767:Ubiquitin-Protein Ligases
chemical_list: C491969:ATG12 protein, S cerevisiae; C498649:ATG16 protein, S cerevisiae; C102268:ATG5 protein, S cerevisiae; D000071192:Autophagy-Related Protein 12; D000071187:Autophagy-Related Protein 5; D000071183:Autophagy-Related Proteins; D002352:Carrier Proteins; D017931:DNA Primers; D008565:Membrane Proteins; D011506:Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D044767:Ubiquitin-Protein Ligases