Apg16p is required for the function of the Apg12p-Apg5p conjugate in the yeast autophagy pathway.
Autophagy is an intracellular bulk degradation system that is ubiquitous for eukaryotic cells. In this process, cytoplasmic components are enclosed in autophagosomes and delivered to lysosomes/vacuoles. We recently found that a protein conjugation system, in which Apg12p is covalently attached to Apg5p, is indispensable for autophagy in yeast. Here, we describe a novel coiled-coil protein, Apg16p, essential for autophagy. Apg16p interacts with Apg12p-conjugated Apg5p and less preferentially with unconjugated Apg5p. Moreover, the coiled-coil domain of Apg16p mediates self-multimerization that leads to cross-linking of Apg5p molecules and formation of a stable protein complex. Apg16p is not essential for the Apg12p-Apg5p conjugation reaction. These results suggest that the Apg12p-Apg5p conjugate requires Apg16p to accomplish its role in the autophagy pathway, and Apg16p is a key molecule as a linker to form the Apg12p-Apg5p-Apg16p multimer.
Department of Cell Biology, National Institute for Basic Biology, Okazaki 444-8585, Japan.
N
N
Mizushima
T
T
Noda
Y
Y
Ohsumi
D000595:Amino Acid Sequence; D001343:Autophagy; D000071187:Autophagy-Related Protein 5; D000071193:Autophagy-Related Protein 7; D000071183:Autophagy-Related Proteins; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D003001:Cloning, Molecular; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D020043:Genes, Essential / Q000235:genetics / Q000502:physiology; D005800:Genes, Fungal / Q000235:genetics / Q000502:physiology; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D011233:Precipitin Tests; D011485:Protein Binding; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins; D017384:Sequence Deletion; D014157:Transcription Factors; D044767:Ubiquitin-Protein Ligases
C498649:ATG16 protein, S cerevisiae; C102268:ATG5 protein, S cerevisiae; C114830:ATG7 protein, S cerevisiae; D000071187:Autophagy-Related Protein 5; D000071183:Autophagy-Related Proteins; D002352:Carrier Proteins; D005656:Fungal Proteins; D008565:Membrane Proteins; D011506:Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D044767:Ubiquitin-Protein Ligases; D000071193:Autophagy-Related Protein 7