Shimura, H. et al. Familial Parkinson disease gene product, Parkin, is a ubiquitin-protein ligase. Nat. Genet. 25, 302-305

Department of Neurology, Juntendo University School of Medicine, Bunkyo-ku, Tokyo, Japan.
Nature Genetics (Impact Factor: 29.35). 08/2000; 25(3):302-5. DOI: 10.1038/77060
Source: PubMed


Autosomal recessive juvenile parkinsonism (AR-JP), one of the most common familial forms of Parkinson disease, is characterized by selective dopaminergic neural cell death and the absence of the Lewy body, a cytoplasmic inclusion body consisting of aggregates of abnormally accumulated proteins. We previously cloned PARK2, mutations of which cause AR-JP (ref. 2), but the function of the gene product, parkin, remains unknown. We report here that parkin is involved in protein degradation as a ubiquitin-protein ligase collaborating with the ubiquitin-conjugating enzyme UbcH7, and that mutant parkins from AR-JP patients show loss of the ubiquitin-protein ligase activity. Our findings indicate that accumulation of proteins that have yet to be identified causes a selective neural cell death without formation of Lewy bodies. Our findings should enhance the exploration of the molecular mechanisms of neurodegeneration in Parkinson disease as well as in other neurodegenerative diseases that are characterized by involvement of abnormal protein ubiquitination, including Alzheimer disease, other tauopathies, CAG triplet repeat disorders and amyotrophic lateral sclerosis.

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Available from: Shuichi Asakawa, Mar 26, 2015
    • "conformation by the REP, which folds back from a region between IBR and RING2. It has been shown before that p.T240R does not interact with the E2 enzyme UbcH7 [Shimura et al., 2000]. In accordance with this, MDS indicated that it might prevent the release of the REP, a prerequisite for E2 binding [Caulfield et al., 2014], whereas the interaction surface for E2 binding stays largely intact. "
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    ABSTRACT: Mutations in the PARKIN/PARK2 gene that result in loss-of-function of the encoded, neuroprotective E3 ubiquitin ligase Parkin cause recessive, familial early-onset Parkinson disease. As an increasing number of rare Parkin sequence variants with unclear pathogenicity are identified, structure-function analyses will be critical to determine their disease relevance. Depending on the specific amino acids affected, several distinct pathomechanisms can result in loss of Parkin function. These include disruption of overall Parkin folding, decreased solubility, and protein aggregation. However pathogenic effects can also result from misregulation of Parkin autoinhibition and of its enzymatic functions. In addition, interference of binding to coenzymes, substrates, and adaptor proteins can affect its catalytic activity too. Herein, we have performed a comprehensive structural and functional analysis of 21 PARK2 missense mutations distributed across the individual protein domains. Using this combined approach, we were able to pinpoint some of the pathogenic mechanisms of individual sequence variants. Similar analyses will be critical in gaining a complete understanding of the complex regulations and enzymatic functions of Parkin. These studies will not only highlight the important residues, but will also help to develop novel therapeutics aimed at activating and preserving an active, neuroprotective form of Parkin.
    Human Mutation 08/2015; 36(8):774-786. · 5.14 Impact Factor
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    • "Elucidation of the pathogenetic mechanism of familial cases, besides being strategic in designing predictive and therapeutic measures for these cases, can provide clues in identifying susceptible sites and networks, whose acquired alterations might be involved/responsible for development and progress in the life-course of sporadic PD. More than 100 different pathogenetic mutations have so far been identified in the parkin (PARK2) gene, encoding parkin, which belongs to the ring between ring fingers (RBR) class of E3 ubiquitin ligases [4] [5]. It is believed that loss of the ubiquitin ligase activity in the parkin mutants impairs degradation by the ubiquitin–proteasome system of specific substrates with accumulation of non-ubiquitinated toxic products leading to neurodegeneration [6] [7]. "
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    ABSTRACT: Parkinson's disease (PD) is the most common neurodegenerative movement disorder caused primarily by selective degeneration of the dopaminergic neurons in substantia nigra. In this work the proteomes extracted from primary fibroblasts of two unrelated, hereditary cases of PD patients, with different parkin mutations, were compared with the proteomes extracted from commercial adult normal human dermal fibroblasts (NHDF) and primary fibroblasts from the healthy mother of one of the two patients. The results show that the fibroblasts from the two different cases of parkin-mutant patients display analogous alterations in the expression level of proteins involved in different cellular functions, like cytoskeleton structure-dynamics, calcium homeostasis, oxidative stress response, proteins and RNA processing. Copyright © 2015. Published by Elsevier B.V.
    Biochimica et Biophysica Acta 06/2015; 1852(9). DOI:10.1016/j.bbadis.2015.06.015 · 4.66 Impact Factor
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    • "However, Ub conjugates linked via one of the other six lysines or via the N-terminal α-amino group of Ub (head-to-tail linkage) can also regulate the function of the protein in a variety of distinct manners (Newton et al. 2008). Soon after its discovery, PARKIN was demonstrated to function as an E3-Ub ligase, ubiquitinating a variety of substrates, including itself (Shimura et al. 2000; Zhang et al. 2000; Imai et al. 2001, 2002; Fallon et al. 2006; Trempe et al. 2009; Sarraf et al. 2013). However, PARKIN was found to exhibit rather poor E3 ligase activity at baseline in a variety of in vitro and cellular assays. "
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    ABSTRACT: Two Parkinson's disease (PD)-associated proteins, the mitochondrial kinase PINK1 and the E3-ubiquitin (Ub) ligase PARKIN, are central to mitochondrial quality control. In this pathway, PINK1 accumulates on defective mitochondria, eliciting the translocation of PARKIN from the cytosol to mediate the clearance of damaged mitochondria via autophagy (mitophagy). Throughout the different stages of mitophagy, post-translational modifications (PTMs) are critical for the regulation of PINK1 and PARKIN activity and function. Indeed, activation and recruitment of PARKIN onto damaged mitochondria involves PINK1-mediated phosphorylation of both PARKIN and Ub. Through a stepwise cascade, PARKIN is converted from an autoinhibited enzyme into an active phospho-Ub-dependent E3 ligase. Upon activation, PARKIN ubiquitinates itself in concert with many different mitochondrial substrates. The Ub conjugates attached to these substrates can in turn be phosphorylated by PINK1, which triggers further cycles of PARKIN recruitment and activation. This feed-forward amplification loop regulates both PARKIN activity and mitophagy. However, the precise steps and sequence of PTMs in this cascade are only now being uncovered. For instance, the Ub conjugates assembled by PARKIN consist predominantly of noncanonical K6-linked Ub chains. Moreover, these modifications are reversible and can be disassembled by deubiquitinating enzymes (DUBs), including Ub-specific protease 8 (USP8), USP15, and USP30. However, PINK1-mediated phosphorylation of Ub can impede the activity of these DUBs, adding a new layer of complexity to the regulation of PARKIN-mediated mitophagy by PTMs. It is therefore evident that further insight into how PTMs regulate the PINK1-PARKIN pathway will be critical for our understanding of mitochondrial quality control. © 2015 Durcan and Fon; Published by Cold Spring Harbor Laboratory Press.
    Genes & Development 05/2015; 29(10):989. DOI:10.1101/gad.262758.115 · 10.80 Impact Factor
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