Protein: Cysteine protease ATG4a (EC 3.4.22.-) (Autophagy-related protein 4 homolog a) (AtAPG4a) (Protein autophagy 4a) (Q8S929)
Organism: Arabidopsis thaliana (Mouse-ear cress)
Function: Cysteine protease that plays a key role in autophagy by mediating both proteolytic activation and delipidation of ATG8 family proteins. The protease activity is required for proteolytic activation of ATG8 family proteins: cleaves the C-terminal amino acid of ATG8 proteins to reveal a C-terminal glycine (By similarity). 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. In addition to the protease activity, also mediates delipidation of PE-conjugated ATG8 proteins (By similarity).
Subcellular location: Cytoplasm {ECO:0000250|UniProtKB:Q8BGE6}.
Sequence: MKALCDRFVPQQCSSSSKSDTHDKSPLVSDSGPSDNKSKFTLWSNVFTSSSSVSQPYRESSTSGHKQVCTTRNGWTAFVKRVSMASGAIRRFQERVLGPNRTGLPSTTSDVWLLGVCYKISADENSGETDTGTVLAALQLDFSSKILMTYRKGFEPFRDTTYTSDVNWGCMIRSSQMLFAQALLFHRLGRAWTKKSELPEQEYLETLEPFGDSEPSAFSIHNLIIAGASYGLAAGSWVGPYAICRAWESLACKKRKQTDSKNQTLPMAVHIVSGSEDGERGGAPILCIEDATKSCLEFSKGQSEWTPIILLVPLVLGLDSVNPRYIPSLVATFTFPQSVGILGGKPGASTYIVGVQEDKGFYLDPHEVQQVVTVNKETPDVDTSSYHCNVLRYVPLESLDPSLALGFYCRDKDDFDDFCLRALKLAEESNGAPLFTVTQTHTAINQSNYGFADDDSEDEREDDWQML
InterPro domains: - IPR005078: Peptidase C54 (family) [74-461]
- IPR038765: Papain-like cysteine peptidase superfamily (homologous_superfamily) [96-439]
- IPR046792: Peptidase C54, catalytic domain (domain) [138-419]
Interaction partners: - Autophagy-related protein 8a
- Autophagy-related protein 8e
- Autophagy-related protein 8f
- Autophagy-related protein 8g
- Autophagy-related protein 8h
- Autophagy-related protein 8i
- Autophagy-related protein 8d
- Autophagy-related protein 8b
- Autophagy-related protein 8c
- Autophagy-related protein 3
Gene Ontology annotations:
Molecular Function (MF): GO:0003674 (molecular function), GO:0003824 (catalytic activity), GO:0016787 (hydrolase activity), GO:0140096 (catalytic activity, acting on a protein), GO:0008233 (peptidase activity), GO:0004175 (endopeptidase activity)
Biological Process (BP): GO:0008150 (biological process), GO:0008152 (metabolic process), GO:0009987 (cellular process), GO:0044238 (primary metabolic process), GO:0044237 (cellular metabolic process), GO:0061919 (process utilizing autophagic mechanism), GO:0071704 (organic substance metabolic process), GO:0009056 (catabolic process), GO:0006807 (nitrogen compound metabolic process), GO:1901564 (organonitrogen compound metabolic process), GO:0043170 (macromolecule metabolic process), GO:0044248 (cellular catabolic process), GO:0019538 (protein metabolic process), GO:0006914 (autophagy), GO:0036211 (protein modification process), GO:0043412 (macromolecule modification), GO:0006508 (proteolysis)
Cellular Component (CC): GO:0005575 (cellular component), GO:0110165 (cellular anatomical entity), GO:0005622 (intracellular anatomical structure), GO:0043226 (organelle), GO:0005737 (cytoplasm), GO:0043229 (intracellular organelle), GO:0005739 (mitochondrion), GO:0043227 (membrane-bounded organelle), GO:0043231 (intracellular membrane-bounded organelle)