A single protease, Apg4B, is specific for the autophagy-related ubiquitin-like proteins GATE-16, MAP1-LC3, GABARAP, and Apg8L

J Biol Chem. 2003 Dec 19;278(51):51841-50. doi: 10.1074/jbc.M308762200. Epub 2003 Oct 6.

Abstract

Apg8 is a ubiquitin-like protein involved in autophagy in yeast. Apg8 is covalently but transiently attached to membrane lipids through the actions of activating, conjugating, and processing/deconjugating enzymes. The mammalian Apg8 homologues GATE-16, GARARAP, and MAP1-LC3 have been implicated in intra-Golgi transport, receptor sorting, and autophagy, respectively. All are served by a single set of activating and conjugating enzymes. Here we identify a novel mammalian Apg8 homologue, which we name Apg8L, and describe the synthesis of electrophilic probes based on the GATE-16, GARARAP, MAP1-LC3, and Apg8L proteins. These probes not only form specific adducts in crude cell lysates, but also allow identification of the cellular proteases specific for the C termini of these Apg8 homologues. We find a single protease, Apg4B/autophagin-1, capable of acting on GATE-16, GABARAP, MAP1-LC3, and Apg8L. The Apg4B/autophagin-1 protease thus serves as a processing/deconjugating enzyme for these four highly divergent mammalian Apg8 homologues.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Apoptosis Regulatory Proteins
  • Autophagy
  • Autophagy-Related Protein 8 Family
  • Autophagy-Related Proteins
  • Carrier Proteins / metabolism*
  • Cysteine Endopeptidases
  • Cytoskeletal Proteins*
  • Exopeptidases / metabolism*
  • Intracellular Signaling Peptides and Proteins
  • Membrane Proteins / metabolism
  • Mice
  • Microtubule-Associated Proteins / metabolism
  • Molecular Probes / chemical synthesis
  • Protein Processing, Post-Translational
  • Saccharomyces cerevisiae Proteins*
  • Sequence Alignment
  • Sequence Homology
  • Ubiquitins / metabolism

Substances

  • ATG8 protein, S cerevisiae
  • Apoptosis Regulatory Proteins
  • Autophagy-Related Protein 8 Family
  • Autophagy-Related Proteins
  • Carrier Proteins
  • Cytoskeletal Proteins
  • GABARAP protein, mouse
  • Gabarapl1 protein, mouse
  • Gabarapl2 protein, mouse
  • Intracellular Signaling Peptides and Proteins
  • Map1lc3b protein, mouse
  • Membrane Proteins
  • Microtubule-Associated Proteins
  • Molecular Probes
  • Saccharomyces cerevisiae Proteins
  • Ubiquitins
  • Exopeptidases
  • Atg4b protein, mouse
  • Cysteine Endopeptidases