UniProt functional annotation for O60260

UniProt code: O60260.

Organism: Homo sapiens (Human).
Taxonomy: Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Mammalia; Eutheria; Euarchontoglires; Primates; Haplorrhini; Catarrhini; Hominidae; Homo.
 
Function: Functions within a multiprotein E3 ubiquitin ligase complex, catalyzing the covalent attachment of ubiquitin moieties onto substrate proteins, such as BCL2, SYT11, CCNE1, GPR37, RHOT1/MIRO1, MFN1, MFN2, STUB1, a 22 kDa O-linked glycosylated isoform of SNCAIP, SEPT5, TOMM20, USP30, ZNF746 and AIMP2. Mediates monoubiquitination as well as 'Lys-48'-linked and 'Lys- 63'-linked polyubiquitination of substrates depending on the context. Participates in the removal and/or detoxification of abnormally folded or damaged protein by mediating 'Lys-63'-linked polyubiquitination of misfolded proteins such as PARK7: 'Lys-63'- linked polyubiquitinated misfolded proteins are then recognized by HDAC6, leading to their recruitment to aggresomes, followed by degradation. Mediates 'Lys-63'-linked polyubiquitination of SNCAIP, possibly playing a role in Lewy-body formation. Mediates monoubiquitination of BCL2, thereby acting as a positive regulator of autophagy. Promotes the autophagic degradation of dysfunctional depolarized mitochondria (mitophagy) by the ubiquitination of mitochondrial proteins such as TOMM20, RHOT1/MIRO1 and USP30 (PubMed:24896179). Mediates 'Lys-48'-linked polyubiquitination of ZNF746, followed by degradation of ZNF746 by the proteasome; possibly playing a role in the regulation of neuron death. Limits the production of reactive oxygen species (ROS). Regulates cyclin- E during neuronal apoptosis. In collaboration with CHPF isoform 2, may enhance cell viability and protect cells from oxidative stress. Independently of its ubiquitin ligase activity, protects from apoptosis by the transcriptional repression of p53/TP53. May protect neurons against alpha synuclein toxicity, proteasomal dysfunction, GPR37 accumulation, and kainate-induced excitotoxicity. May play a role in controlling neurotransmitter trafficking at the presynaptic terminal and in calcium-dependent exocytosis. May represent a tumor suppressor gene.
 
Enzyme regulation: In the autoinhibited state the side chain of Phe-463 inserts into a hydrophobic groove in RING-0, occluding the ubiquitin acceptor site Cys-431, whereas the REP repressor element binds RING-1 and blocks its E2-binding site (PubMed:23727886, PubMed:23770887). Activation of PARK2 requires 2 steps: (1) phosphorylation at Ser-65 by PINK1 and (2) binding to phosphorylated ubiquitin, leading to unlock repression of the catalytic Cys-431 by the RING-0 region via an allosteric mechanism and converting PARK2 to its fully-active form (PubMed:24784582).
Pathway: Protein modification; protein ubiquitination.
Subunit: Forms an E3 ubiquitin ligase complex with UBE2L3 or UBE2L6. Mediates 'Lys-63'-linked polyubiquitination by associating with UBE2V1. Part of a SCF-like complex, consisting of PARK2, CUL1 and FBXW7. Interacts with SNCAIP. Binds to the C2A and C2B domains of SYT11. Interacts and regulates the turnover of SEPT5. Part of a complex, including STUB1, HSP70 and GPR37. The amount of STUB1 in the complex increases during ER stress. STUB1 promotes the dissociation of HSP70 from PARK2 and GPR37, thus facilitating PARK2-mediated GPR37 ubiquitination. HSP70 transiently associates with unfolded GPR37 and inhibits the E3 activity of PARK2, whereas, STUB1 enhances the E3 activity of PARK2 through promotion of dissociation of HSP70 from PARK2-GPR37 complexes. Interacts with PSMD4 and PACRG. Interacts with LRRK2. Interacts with RANBP2. Interacts with SUMO1 but not SUMO2, which promotes nuclear localization and autoubiquitination. Interacts (via first RING- type domain) with AIMP2 (via N-terminus). Interacts with PSMA7 and RNF41. Interacts with PINK1. Interacts with CHPF, the interaction with isoform 2 may facilitate PARK2 transport into the mitochondria. Interacts with MFN2 (phosphorylated), promotes PARK2 localization in dysfunctional depolarized mitochondria. Interacts with FBXO7; this promotes translocation to dysfunctional depolarized mitochondria. Interacts with heat shock protein 70 family members, including HSPA1L, HSPA1A and HSPA8; interaction HSPA1L promotes translocation to damaged mitochondria. Interacts with BAG4 and, to a lesser extent, BAG5; interaction with BAG4 inhibits translocation to damaged mitochondria.
Subcellular location: Cytoplasm, cytosol. Nucleus. Endoplasmic reticulum. Mitochondrion. Note=Mainly localizes in the cytosol. Co-localizes with SYT11 in neutrites. Co-localizes with SNCAIP in brainstem Lewy bodies. Mitochondrial localization gradually increases with cellular growth. Also relocates to dysfunctional mitochondria that have lost the mitochondrial membrane potential; recruitment to mitochondria is PINK1-dependent.
Tissue specificity: Highly expressed in the brain including the substantia nigra. Expressed in heart, testis and skeletal muscle. Expression is down-regulated or absent in tumor biopsies, and absent in the brain of PARK2 patients. Overexpression protects dopamine neurons from kainate-mediated apoptosis. Found in serum (at protein level).
Domain: The ubiquitin-like domain binds the PSMD4 subunit of 26S proteasomes.
Domain: The RING-type 1 zinc finger domain is required to repress p53/TP53 transcription (PubMed:19801972).
Ptm: Auto-ubiquitinates in an E2-dependent manner leading to its own degradation. Also polyubiquitinated by RNF41 for proteasomal degradation.
Ptm: S-nitrosylated. The inhibition of PARK2 ubiquitin E3 ligase activity by S-nitrosylation could contribute to the degenerative process in PD by impairing the ubiquitination of PARK2 substrates.
Ptm: Phosphorylation at Ser-65 by PINK1 contributes to activate PARK2 activity. It is however not sufficient and requires binding to phosphorylated ubiquitin as well.
Disease: Parkinson disease (PARK) [MIM:168600]: A complex neurodegenerative disorder characterized by bradykinesia, resting tremor, muscular rigidity and postural instability. Additional features are characteristic postural abnormalities, dysautonomia, dystonic cramps, and dementia. The pathology of Parkinson disease involves the loss of dopaminergic neurons in the substantia nigra and the presence of Lewy bodies (intraneuronal accumulations of aggregated proteins), in surviving neurons in various areas of the brain. The disease is progressive and usually manifests after the age of 50 years, although early-onset cases (before 50 years) are known. The majority of the cases are sporadic suggesting a multifactorial etiology based on environmental and genetic factors. However, some patients present with a positive family history for the disease. Familial forms of the disease usually begin at earlier ages and are associated with atypical clinical features. Note=Disease susceptibility may be associated with variations affecting the gene represented in this entry. Heterozygous mutations act as susceptibility alleles for late- onset Parkinson disease (PubMed:12730996 and PubMed:12629236).
Disease: Parkinson disease 2 (PARK2) [MIM:600116]: A neurodegenerative disorder characterized by bradykinesia, rigidity, postural instability, tremor, and onset usually before 40. It differs from classic Parkinson disease by early DOPA- induced dyskinesia, diurnal fluctuation of the symptoms, sleep benefit, dystonia and hyper-reflexia. Dementia is absent. Pathologically, patients show loss of dopaminergic neurons in the substantia nigra, similar to that seen in Parkinson disease; however, Lewy bodies (intraneuronal accumulations of aggregated proteins) are absent. Note=The disease is caused by mutations affecting the gene represented in this entry.
Disease: Note=Defects in PARK2 may be involved in the development and/or progression of ovarian cancer.
Miscellaneous: The parkin locus (PRKN), adjacent to the 6q telomere is hyper-recombinable and lies within FRA6E, the third most common fragile site in tumor tissue.
Miscellaneous: Members of the RBR family are atypical E3 ligases. They interact with the E2 conjugating enzyme UBE2L3 and function like HECT-type E3 enzymes: they bind E2s via the first RING domain, but require an obligate trans-thiolation step during the ubiquitin transfer, requiring a conserved cysteine residue in the second RING domain (PubMed:21532592).
Similarity: Belongs to the RBR family. Parkin subfamily.
Similarity: Contains 1 IBR-type zinc finger.
Similarity: Contains 3 RING-type zinc fingers.
Similarity: Contains 1 ubiquitin-like domain.

Annotations taken from UniProtKB at the EBI.