Structural highlights
Function
[ATG4B_HUMAN] Cysteine protease required for autophagy, which cleaves the C-terminal part of MAP1LC3, GABARAPL1, GABARAPL2 and GABARAP, allowing the liberation of form I. A subpopulation of form I is subsequently converted to a smaller form (form II). Form II, with a revealed C-terminal glycine, is considered to be the phosphatidylethanolamine (PE)-conjugated form, and has the capacity for the binding to autophagosomes. Also mediates the lipid deconjugation required for target recycling.[1] [2] [MLP3B_RAT] Probably involved in formation of autophagosomal vacuoles (autophagosomes).
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
Atg8 is conjugated to phosphatidylethanolamine (PE) by ubiquitin-like conjugation reactions. Atg8 has at least two functions in autophagy: membrane biogenesis and target recognition. Regulation of PE conjugation and deconjugation of Atg8 is crucial for these functions in which Atg4 has a critical function by both processing Atg8 precursors and deconjugating Atg8-PE. Here, we report the crystal structures of catalytically inert human Atg4B (HsAtg4B) in complex with processed and unprocessed forms of LC3, a mammalian orthologue of yeast Atg8. On LC3 binding, the regulatory loop and the N-terminal tail of HsAtg4B undergo large conformational changes. The regulatory loop masking the entrance of the active site of free HsAtg4B is lifted by LC3 Phe119, so that a groove is formed along which the LC3 tail enters the active site. At the same time, the N-terminal tail masking the exit of the active site of HsAtg4B in the free form is detached from the enzyme core and a large flat surface is exposed, which might enable the enzyme to access the membrane-bound LC3-PE.
The structure of Atg4B-LC3 complex reveals the mechanism of LC3 processing and delipidation during autophagy.,Satoo K, Noda NN, Kumeta H, Fujioka Y, Mizushima N, Ohsumi Y, Inagaki F EMBO J. 2009 May 6;28(9):1341-50. Epub 2009 Mar 26. PMID:19322194[3]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Kabeya Y, Mizushima N, Yamamoto A, Oshitani-Okamoto S, Ohsumi Y, Yoshimori T. LC3, GABARAP and GATE16 localize to autophagosomal membrane depending on form-II formation. J Cell Sci. 2004 Jun 1;117(Pt 13):2805-12. PMID:15169837 doi:10.1242/jcs.01131
- ↑ Satoo K, Noda NN, Kumeta H, Fujioka Y, Mizushima N, Ohsumi Y, Inagaki F. The structure of Atg4B-LC3 complex reveals the mechanism of LC3 processing and delipidation during autophagy. EMBO J. 2009 May 6;28(9):1341-50. Epub 2009 Mar 26. PMID:19322194 doi:10.1038/emboj.2009.80
- ↑ Satoo K, Noda NN, Kumeta H, Fujioka Y, Mizushima N, Ohsumi Y, Inagaki F. The structure of Atg4B-LC3 complex reveals the mechanism of LC3 processing and delipidation during autophagy. EMBO J. 2009 May 6;28(9):1341-50. Epub 2009 Mar 26. PMID:19322194 doi:10.1038/emboj.2009.80
