Distinct mechanisms for processing autophagy protein LC3-PE by RavZ and ATG4B.

Distinct mechanisms for processing autophagy protein LC3-PE by RavZ and ATG4B. Chembiochem. 2020 Jul 20;: Authors: Yang A, Pantoom S, Wu Y Abstract Autophagy is a conserved catabolic process involved in the elimination of proteins, organelles and pathogens. Lipidated LC3 proteins that are conjugated to phosphatidylethanolamine (PE) play a key role in autophagosome biogenesis. Endogenous ATG4-mediated deconjugation of LC3-PE is required for LC3 recycling. However, the Legionella effector RavZ irreversibly deconjugates LC3-PE to inhibit autophagy. It is not clear how ATG4 and RavZ process LC3-PE with distinct modes. Herein, a series of semi-synthetic LC3-PE proteins containing C-terminal mutations or insertions were used to investigate the relationship of the C-terminal structure of LC3-PE with ATG4/RavZ-mediated deconjugation. Using a combination of molecular docking and biochemical assays, we found that Gln 116 , Phe 119 and Gly 120 of LC3-PE are required for the cleavage by both RavZ and ATG4B, while Glu 117 (LC3) is specific for the cleavage by RavZ. The molecular ruler mechanism exists in the active site of ATG4B but not in RavZ. Met 63 and Gln 64 at the active site of RavZ are involved in accommodating LC3 C-terminal motif. Our findings show that the distinct binding modes of LC3 C-terminal motif (116-120) with ATG4 and RavZ may determine the specificity of cleavage site. PMID: 32686895 [PubMed - as supplied by publisher]
Source: Chembiochem - Category: Biochemistry Authors: Tags: Chembiochem Source Type: research