| IED ID | IndEnz0002014405 |
| Enzyme Type ID | protease014405 |
| Protein Name |
Cysteine protease ATG4B EC 3.4.22.- Autophagy-related protein 4 homolog B |
| Gene Name | Atg4b |
| Organism | Rattus norvegicus (Rat) |
| Taxonomic Lineage | cellular organisms Eukaryota Opisthokonta Metazoa Eumetazoa Bilateria Deuterostomia Chordata Craniata Vertebrata Gnathostomata (jawed vertebrates) Teleostomi Euteleostomi Sarcopterygii Dipnotetrapodomorpha Tetrapoda Amniota Mammalia Theria Eutheria Boreoeutheria Euarchontoglires Glires (Rodents and rabbits) Rodentia Myomorpha (mice and others) Muroidea Muridae Murinae Rattus Rattus norvegicus (Rat) |
| Enzyme Sequence | MDAATLTYDTLRFAEFEDFPETSEPVWILGRKYSIFTEKDEILSDVASRLWFTYRRNFPAIGGTGPTSDTGWGCMLRCGQMIFAQALVCRHLGRDWRWTQRKRQPDSYFSVLNAFLDRKDSYYSIHQIAQMGVGEGKSIGQWYGPNTVAQVLKKLAVFDTWSSLAVHIAMDNTVVMEEIRRLCRASLPCAGAAALSMESERHCNGLPAGAEVTNRPLAWRPLVLLIPLRLGLTDINEAYVETLKHCFMMPQSLGVIGGKPNSAHYFIGYVGEELIYLDPHTTQPAVELTDSCFIPDESFHCQHPPCRMGIGELDPSIAVGFFCKTEEDFNDWCQQVKKLSQLGGALPMFELVEQQPSHLACQDVLNLSLDSSDVERLERFFDSEDEDFEILSL |
| Enzyme Length | 393 |
| Uniprot Accession Number | A0A0G2QC33 |
| Absorption | |
| Active Site | ACT_SITE 74; /note=Nucleophile; /evidence=ECO:0000250|UniProtKB:Q9Y4P1; ACT_SITE 278; /evidence=ECO:0000250|UniProtKB:Q9Y4P1; ACT_SITE 280; /evidence=ECO:0000250|UniProtKB:Q9Y4P1 |
| Activity Regulation | ACTIVITY REGULATION: Inhibited by N-ethylmaleimide. Redox-regulated during autophagy since reducing conditions activate ATG4A whereas an oxidizing environment such as the presence of H(2)O(2) inhibits its activity. The cysteine protease activity compounds is inhibited by styrylquinoline compounds 4-28 and LV-320. {ECO:0000250|UniProtKB:Q9Y4P1}. |
| Binding Site | |
| Calcium Binding | |
| catalytic Activity | CATALYTIC ACTIVITY: Reaction=[protein]-C-terminal L-amino acid-glycyl-phosphatidylethanolamide + H2O = [protein]-C-terminal L-amino acid-glycine + a 1,2-diacyl-sn-glycero-3-phosphoethanolamine; Xref=Rhea:RHEA:67548, Rhea:RHEA-COMP:17323, Rhea:RHEA-COMP:17324, ChEBI:CHEBI:15377, ChEBI:CHEBI:64612, ChEBI:CHEBI:172940, ChEBI:CHEBI:172941; Evidence={ECO:0000250|UniProtKB:Q9Y4P1};PhysiologicalDirection=left-to-right; Xref=Rhea:RHEA:67549; Evidence={ECO:0000250|UniProtKB:Q9Y4P1}; CATALYTIC ACTIVITY: Reaction=[protein]-C-terminal L-amino acid-glycyl-phosphatidylserine + H2O = [protein]-C-terminal L-amino acid-glycine + a 1,2-diacyl-sn-glycero-3-phospho-L-serine; Xref=Rhea:RHEA:67576, Rhea:RHEA-COMP:17324, Rhea:RHEA-COMP:17326, ChEBI:CHEBI:15377, ChEBI:CHEBI:57262, ChEBI:CHEBI:172940, ChEBI:CHEBI:172942; Evidence={ECO:0000250|UniProtKB:Q9Y4P1};PhysiologicalDirection=left-to-right; Xref=Rhea:RHEA:67577; Evidence={ECO:0000250|UniProtKB:Q9Y4P1}; |
| DNA Binding | |
| EC Number | 3.4.22.- |
| Enzyme Function | FUNCTION: Cysteine protease that plays a key role in autophagy by mediating both proteolytic activation and delipidation of ATG8 family proteins. Required for canonical autophagy (macroautophagy), non-canonical autophagy as well as for mitophagy. The protease activity is required for proteolytic activation of ATG8 family proteins: cleaves the C-terminal amino acid of ATG8 proteins MAP1LC3A, MAP1LC3B, MAP1LC3C, GABARAPL1, GABARAPL2 and GABARAP, to reveal a C-terminal glycine. Exposure of the glycine at the C-terminus is essential for ATG8 proteins conjugation to phosphatidylethanolamine (PE) and insertion to membranes, which is necessary for autophagy. Protease activity is also required to counteract formation of high-molecular weight conjugates of ATG8 proteins (ATG8ylation): acts as a deubiquitinating-like enzyme that removes ATG8 conjugated to other proteins, such as ATG3. In addition to the protease activity, also mediates delipidation of ATG8 family proteins. Catalyzes delipidation of PE-conjugated forms of ATG8 proteins during macroautophagy. Also involved in non-canonical autophagy, a parallel pathway involving conjugation of ATG8 proteins to single membranes at endolysosomal compartments, by catalyzing delipidation of ATG8 proteins conjugated to phosphatidylserine (PS). Compared to other members of the family (ATG4A, ATG4C or ATG4C), constitutes the major protein for proteolytic activation of ATG8 proteins, while it displays weaker delipidation activity than other ATG4 paralogs. Involved in phagophore growth during mitophagy independently of its protease activity and of ATG8 proteins: acts by regulating ATG9A trafficking to mitochondria and promoting phagophore-endoplasmic reticulum contacts during the lipid transfer phase of mitophagy. {ECO:0000250|UniProtKB:Q9Y4P1}. |
| Temperature Dependency | |
| PH Dependency | |
| Pathway | |
| nucleotide Binding | |
| Features | Active site (3); Alternative sequence (1); Chain (1); Disulfide bond (3); Modified residue (8); Motif (1) |
| Keywords | Acetylation;Alternative splicing;Autophagy;Cytoplasm;Cytoplasmic vesicle;Disulfide bond;Endoplasmic reticulum;Glycoprotein;Hydrolase;Isopeptide bond;Mitochondrion;Phosphoprotein;Protease;Protein transport;Reference proteome;S-nitrosylation;Thiol protease;Transport;Ubl conjugation;Ubl conjugation pathway |
| Interact With | |
| Induction | |
| Subcellular Location | SUBCELLULAR LOCATION: Cytoplasm {ECO:0000250|UniProtKB:Q9Y4P1}. Cytoplasm, cytosol {ECO:0000250|UniProtKB:Q9Y4P1}. Cytoplasmic vesicle, autophagosome {ECO:0000250|UniProtKB:Q9Y4P1}. Endoplasmic reticulum {ECO:0000250|UniProtKB:Q9Y4P1}. Mitochondrion {ECO:0000250|UniProtKB:Q9Y4P1}. Note=Mainly localizes to the cytoplasm, including cytosol. A samll potion localizes to mitochondria; phosphorylation at Ser-34 promotes localization to mitochondria. {ECO:0000250|UniProtKB:Q9Y4P1}. |
| Modified Residue | MOD_RES 1; /note=N-acetylmethionine; /evidence=ECO:0000250|UniProtKB:Q9Y4P1; MOD_RES 34; /note=Phosphoserine; /evidence=ECO:0000250|UniProtKB:Q9Y4P1; MOD_RES 189; /note=S-nitrosocysteine; /evidence=ECO:0000250|UniProtKB:Q9Y4P1; MOD_RES 292; /note=S-nitrosocysteine; /evidence=ECO:0000250|UniProtKB:Q9Y4P1; MOD_RES 301; /note=S-nitrosocysteine; /evidence=ECO:0000250|UniProtKB:Q9Y4P1; MOD_RES 316; /note=Phosphoserine; /evidence=ECO:0000250|UniProtKB:Q9Y4P1; MOD_RES 383; /note=Phosphoserine; /evidence=ECO:0000250|UniProtKB:Q9Y4P1; MOD_RES 392; /note=Phosphoserine; /evidence=ECO:0000250|UniProtKB:Q9Y4P1 |
| Post Translational Modification | PTM: Phosphorylation at Ser-383 and Ser-392 promotes autophagy by increasing protein delipidation activity without affecting proteolytic activation of ATG8 proteins. Phosphorylation at Ser-316 by ULK1 inhibits autophagy by decreasing both proteolytic activation and delipidation activities. Phosphorylation at Ser-316 is dephosphorylated by protein phosphatase 2A (PP2A). Phosphorylation at Ser-34 by AKT2 promotes its hydrolase activity, leading to increased proteolytic activation and delipidation of ATG8 family proteins. Phosphorylation at Ser-34 by AKT1 promotes mitochondrial localization and inhibition of the F1F0-ATP synthase activity, leading to elevation of mitochondrial reactive oxygen species (ROS). {ECO:0000250|UniProtKB:Q9Y4P1}.; PTM: Ubiquitinated by RNF5, leading to its degradation by the proteasome. {ECO:0000250|UniProtKB:Q9Y4P1}.; PTM: S-nitrosylation in response to high glucose decreases both proteolytic activation and delipidation activities. {ECO:0000269|PubMed:28633005}.; PTM: O-glycosylated by OGT, leading to increase protease activity, thereby promoting the proteolytic activation of ATG8 family proteins. {ECO:0000250|UniProtKB:Q9Y4P1}.; PTM: Forms reversible intrachain disulfide bonds in response to oxidative stress. Forms interchain disulfide bonds, leading to formation of homooligomers in response to oxidation. {ECO:0000250|UniProtKB:Q9Y4P1}. |
| Signal Peptide | |
| Structure 3D | |
| Cross Reference PDB | - |
| Mapped Pubmed ID | 16874114; |
| Motif | MOTIF 388..391; /note=LIR; /evidence=ECO:0000250|UniProtKB:Q9Y4P1 |
| Gene Encoded By | |
| Mass | 44,364 |
| Kinetics | |
| Metal Binding | |
| Rhea ID | RHEA:67548; RHEA:67549; RHEA:67576; RHEA:67577 |
| Cross Reference Brenda |