7t3x
From Proteopedia
Structure of unphosphorylated Pediculus humanus (Ph) PINK1 D334A mutant
Structural highlights
FunctionPINK1_PEDHC Acts as a serine/threonine-protein kinase (PubMed:22645651, PubMed:26161729, PubMed:29160309). Exhibits a substrate preference for proline at position P+1 and a general preference at several residues for basic residues such as arginine (By similarity). Also exhibits moderate preferences for a phosphotyrosine at position P-3 and a tryptophan at P-5 (By similarity). Critical to mitochondrial homeostasis it mediates several pathways that maintain mitochondrial health and function (By similarity) Protects against mitochondrial dysfunction during cellular stress by phosphorylating mitochondrial proteins such as park and likely Drp1, to coordinate mitochondrial quality control mechanisms that remove and replace dysfunctional mitochondrial components (PubMed:26161729). Depending on the severity of mitochondrial damage and/or dysfunction, activity ranges from preventing apoptosis and stimulating mitochondrial biogenesis to regulating mitochondrial dynamics and eliminating severely damaged mitochondria via mitophagy (By similarity). Appears to be particularly important in maintaining the physiology and function of cells with high energy demands that are undergoing stress or altered metabolic environment, including spermatids, muscle cells and neurons such as the dopaminergic (DA) neurons (By similarity). Mediates the translocation and activation of park at the outer membrane (OMM) of dysfunctional/depolarized mitochondria (PubMed:26161729). At the OMM of damaged mitochondria, phosphorylates pre-existing polyubiquitin chains, the Pink1-phosphorylated polyubiquitin then recruits park from the cytosol to the OMM where park is fully activated by phosphorylation at 'Ser-94' by Pink1 (By similarity). When cellular stress results in irreversible mitochondrial damage, functions with park to promote the clearance of dysfunctional and/or depolarized mitochondria by selective autophagy (mitophagy) (By similarity). The Pink1-park pathway also promotes fission and/or inhibits fusion of damaged mitochondria, by phosphorylating and thus promoting the park-dependent degradation of proteins involved in mitochondrial fusion/fission such as Marf, Opa1 and fzo (By similarity). This prevents the refusion of unhealthy mitochondria with the mitochondrial network or initiates mitochondrial fragmentation facilitating their later engulfment by autophagosomes (By similarity). Also likely to promote mitochondrial fission independently of park and Atg7-mediated mitophagy, via the phosphorylation and activation of Drp1 (By similarity). Regulates motility of damaged mitochondria by phosphorylating Miro which likely promotes its park-dependent degradation by the proteasome; in motor neurons, this inhibits mitochondrial intracellular anterograde transport along the axons which probably increases the chance of the mitochondria being eliminated in the soma (By similarity). The Pink1-park pathway is also involved in mitochondrial regeneration processes such as promoting mitochondrial biogenesis, activating localized mitochondrial repair, promoting selective turnover of mitochondrial proteins and initiating the mitochondrial import of endogenous proteins (By similarity). Involved in mitochondrial biogenesis by promoting the park-dependent ubiquitination of transcriptional repressor Paris which leads to its subsequent proteasomal degradation and allows activation of the transcription factor srl (By similarity). Functions with park to promote localized mitochondrial repair by activating the translation of specific nuclear-encoded mitochondrial RNAs (nc-mtRNAs) on the mitochondrial surface, including several key electron transport chain component nc-mtRNAs (By similarity). During oogenesis, phosphorylates and inactivates larp on the membrane of defective mitochondria, thus impairing local translation and mtDNA replication and consequently, reducing transmission of deleterious mtDNA mutations to the mature oocyte (By similarity). Phosphorylates the mitochondrial acyl-CoA dehydrogenase Mcad, and appears to be important for maintaining fatty acid and amino acid metabolism via a mechanism that is independent of it's role in maintaining production of ATP (By similarity).[UniProtKB:D6WMX4][UniProtKB:Q0KHV6][1] [2] [3] Publication Abstract from PubMedMutations in the protein kinase PINK1 lead to defects in mitophagy and cause autosomal recessive early onset Parkinson's Disease (EOPD)(1,2). PINK1 has many unique features that enable it to phosphorylate ubiquitin and the ubiquitin-like domain of Parkin(3-9). Structural analysis of PINK1 from diverse insect species(10-12) with and without ubiquitin provided snapshots of distinct structural states yet did not explain how PINK1 is activated. We here elucidate the activation mechanism of PINK1 by crystallography and cryo-EM. A crystal structure of unphosphorylated Pediculus humanus corporis (Ph) PINK1 resolves a previously omitted N-terminal helix revealing how unphosphorylated yet active PINK1 is oriented on mitochondria. We further reveal a 2.35 A cryo-EM structure of a symmetric PhPINK1 dimer trapped during the process of trans-autophosphorylation, and a 3.1 A cryo-EM structure of phosphorylated PhPINK1 in the process of undergoing a conformational change to become an active ubiquitin kinase. Structures and phosphorylation studies further identify a role for regulatory PINK1 oxidation. Together, our work delineates the complete activation mechanism of PINK1, illuminates how PINK1 interacts with the mitochondrial outer membrane, and reveals how PINK1 activity may be modulated by mitochondrial reactive oxygen species. Activation mechanism of PINK1.,Gan ZY, Callegari S, Cobbold SA, Cotton TR, Mlodzianoski MJ, Schubert AF, Geoghegan ND, Rogers KL, Leis A, Dewson G, Glukhova A, Komander D Nature. 2021 Dec 21. pii: 10.1038/s41586-021-04340-2. doi:, 10.1038/s41586-021-04340-2. PMID:34933320[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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