Kinetics comparisons of mammalian Atg4 homologues indicate selective preferences toward diverse Atg8 substrates

Min Li, Yifeng Hou, Jinsong Wang, Xiaoyun Chen, Zhi Ming Shao, Xiao Ming Yin

Research output: Contribution to journalArticle

121 Scopus citations


The Atg4 cysteine proteases are required for processing Atg8 for the latter to be conjugated to phosphatidylethanolamine on autophagosomal membranes, a key step in autophagosome biogenesis. Notably, whereas there are only one atg4 and one atg8 gene in the yeast, the mammals have four Atg4 homologues and six Atg8 homologues. The Atg8 homologues seem to play different roles in autophagosome biogenesis, and previous studies had indicated that they could be differentially processed by Atg4 homologues. The present study provided the first detailed kinetics analysis of all four Atg4 homologues against four representative Atg8 homologues. The data indicated that Atg4B possessed the broadest spectrum against all substrates, followed by Atg4A, whereas Atg4C and Atg4D had minimal activities as did the catalytic mutant of Atg4B (C74S). On the other hand, GATE-16 seemed to be the overall best substrate for Atg4 proteases. The kinetics parameters of Atg4B were also affected by its structure and that of the substrates, indicating a process of induced fit. The determination of the kinetics parameters of the various Atg4-Atg8 pairs provides a base for the understanding of the potential selective impact of the reaction on autophagosome biogenesis.

Original languageEnglish (US)
Pages (from-to)7327-7338
Number of pages12
JournalJournal of Biological Chemistry
Issue number9
StatePublished - Mar 4 2011

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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