Hanada T, et al. (2007) The Atg12-Atg5 Conjugate Has a Novel E3-like Activity for Protein Lipidation in Autophagy. J Biol Chem 282(52):37298-302
Abstract: Autophagy is a bulk degradation process in eukaryotic cells: autophagosomes enclose cytoplasmic components for degradation in the lysosome/vacuole. Autophagosome formation requires two ubiquitin-like conjugation systems, the Atg12 and Atg8 systems, which are tightly associated with expansion of autophagosomal membrane. Previous studies have suggested that there is a hierarchy between these systems: the Atg12 system is located upstream of the Atg8 system in the context of Atg proteins organization; however, the concrete molecular relationship is unclear. Here, we show using an in vitro Atg8 conjugation system that the Atg12-Atg5 conjugate, but not unconjugated Atg12 or Atg5, strongly enhance the formation of the other conjugate, Atg8-PE. The Atg12-Atg5 conjugate promotes the transfer of Atg8 from Atg3 to the substrate, phosphatidylethanolamine (PE) by stimulating the activity of Atg3. We also show that the Atg12-Atg5 conjugate interacts with both Atg3 and PE-containing liposomes. These results indicate that the Atg12-Atg5 conjugate is an E3-like enzyme for Atg8-PE conjugation reaction, distinctively promoting protein-lipid conjugation.
|Status: Published||Type: Journal Article||PubMed ID: 17986448|
Topics addressed in this paper
Number of different genes curated to this paper: 4
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