7eu4
Crystal structure of plant ATG12 complexed with the AIM12 of ATG3
Structural highlights
FunctionAT12B_ARATH Ubiquitin-like protein involved in cytoplasm to vacuole transport (Cvt) and autophagy vesicles formation. Conjugation with ATG5 through a ubiquitin-like conjugating system involving also ATG7 as an E1-like activating enzyme and ATG10 as an E2-like conjugating enzyme, is essential for its function. ATG12/ATG5 conjugate has an essential role in plant nutrient recycling. Publication Abstract from PubMedAutophagy is an intracellular degradation system regulating cellular homeostasis. The two ubiquitin-like modification systems named the Atg8 system and the Atg12 system are essential for autophagy. Atg8 and Atg12 are ubiquitin-like proteins covalently conjugated with a phosphatidylethanolamine (PE) and Atg5, respectively, via enzymatic reactions. The Atg8-PE conjugate binds to autophagic membranes and recruits various proteins through direct interaction, whereas the Atg12-Atg5 conjugate recognizes Atg3, the E2 enzyme for Atg8, and facilitates Atg8-PE conjugation by functioning as the E3 enzyme. Although structural and biochemical analyses have well established the Atg8-family interacting motif (AIM), studies on the interacting sequence for Atg12 are rare (only one example for human ATG12-ATG3), thereby making it challenging to define a binding motif. Here we determined the crystal structure of the plant ATG12b as a complex with the ATG12b-binding region of ATG3 and revealed that ATG12b recognizes the aspartic acid (Asp)-methionine (Met) motif in ATG3 via a hydrophobic pocket and a basic residue, which we confirmed critical for the complex formation by mutational analysis. This recognition mode is similar to that reported between human ATG12 and ATG3, suggesting that the Asp-Met sequence is a conserved Atg12-interacting motif (AIM12). These data suggest that AIM12 mediates E2-E3 interaction during Atg8 lipidation and provide structural basis for developing chemicals that regulate autophagy by targeting Atg12-family proteins. Atg12-Interacting Motif Is Crucial for E2-E3 Interaction in Plant Atg8 System.,Matoba K, Noda NN Biol Pharm Bull. 2021 Sep 1;44(9):1337-1343. doi: 10.1248/bpb.b21-00439. Epub , 2021 Jul 1. PMID:34193767[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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