scholarly journals Deciphering the activation of the E3 ubiquitin ligase parkin

2014 ◽  
Vol 70 (a1) ◽  
pp. C836-C836
Author(s):  
Véronique Sauvé ◽  
Kalle Gehring

Parkin is an E3 ubiquitin ligase responsible for some autosomal recessive forms of Parkinson's disease. Even though parkin is a RING-type E3 ligase, it uses a hybrid RING/HECT mechanism for its activity. The crystal structures of full-length and the RING0-RING1-In-Between-RING-RING2 module of parkin reveal a conformation of parkin in which its E2 binding site is too far from its catalytic cysteine for the transfer of ubiquitin [1]. Many intramolecular interactions occur between the different RING domains, as well as with a repressor element, which, with RING0, are unique to parkin. Mutations of residues involved in those interactions lead to an increase of parkin activity. This suggests that parkin adopts an auto-inhibited state in basal conditions. Therefore, under stress-response conditions, parkin needs to undergo molecular rearrangements, modulated by post-translational modification and/or interactions with other proteins, to become active. The phosphorylation of serine 65 in the Ubl domain of parkin by Pink1, a kinase also found mutated in some Parkinson's patient, was shown to increase the activity of parkin. Recent publications have demonstrated that ubiquitin is also phosphorylated by Pink1 and, furthermore, that phosphorylated ubiquitin could activate parkin [2,3]. We have used different techniques of structural biology and protein-protein interactions to further characterize the interaction of phosphorylated ubiquitin with parkin. This work provides insight into the mechanism of activation of parkin and that causes Parkinson's disease.

Viruses ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 897
Author(s):  
Ernesto Estrada

Extensive extrapulmonary damages in a dozen of organs/systems, including the central nervous system (CNS), are reported in patients of the coronavirus disease 2019 (COVID-19). Three cases of Parkinson’s disease (PD) have been reported as a direct consequence of COVID-19. In spite of the scarce data for establishing a definitive link between COVID-19 and PD, some hypotheses have been proposed to explain the cases reported. They, however, do not fit well with the clinical findings reported for COVID-19 patients, in general, and for the PD cases reported, in particular. Given the importance of this potential connection, we present here a molecular-level mechanistic hypothesis that explains well these findings and will serve to explore the potential CNS damage in COVID-19 patients. The model explaining the cascade effects from COVID-19 to CNS is developed by using bioinformatic tools. It includes the post-translational modification of host proteins in the lungs by viral proteins, the transport of modified host proteins via exosomes out the lungs, and the disruption of protein-protein interaction in the CNS by these modified host proteins. Our hypothesis is supported by finding 44 proteins significantly expressed in the CNS which are associated with PD and whose interactions can be perturbed by 24 host proteins significantly expressed in the lungs. These 24 perturbators are found to interact with viral proteins and to form part of the cargoes of exosomes in human tissues. The joint set of perturbators and PD-vulnerable proteins form a tightly connected network with significantly more connections than expected by selecting a random cluster of proteins of similar size from the human proteome. The molecular-level mechanistic hypothesis presented here provides several routes for the cascading of effects from the lungs of COVID-19 patients to PD. In particular, the disruption of autophagy/ubiquitination processes appears as an important mechanism that triggers the generation of large amounts of exosomes containing perturbators in their cargo, which would insult several PD-vulnerable proteins, potentially triggering Parkinsonism in COVID-19 patients.


2018 ◽  
Author(s):  
Wei Yi ◽  
Emma J. MacDougall ◽  
Matthew Y. Tang ◽  
Andrea I. Krahn ◽  
Ziv Gan-Or ◽  
...  

AbstractMutations in Parkin (PARK2), which encodes an E3 ubiquitin ligase implicated in mitophagy, are the most common cause of early onset Parkinson’s Disease (PD). Hundreds of naturally occurring Parkin variants have been reported, both in PD patient and population databases. However, the effects of the majority of these variants on the function of Parkin and in PD pathogenesis remains unknown. Here we develop a framework for classification of the pathogenicity of Parkin variants based on the integration of clinical and functional evidence – including measures of mitophagy and protein stability, and predictive structural modeling – and assess 51 naturally occurring Parkin variants accordingly. Surprisingly, only a minority of Parkin variants, even among those previously associated with PD, disrupted Parkin function. Moreover, a few of these naturally occurring Parkin variants actually enhanced mitophagy. Interestingly, impaired mitophagy in several of the most common pathogenic Parkin variants could be rescued both by naturally-occurring (p.V224A) and structure-guided designer (p.W403A; p.F146A) hyperactive Parkin variants. Together, the findings provide a coherent framework to classify Parkin variants based on pathogenicity and suggest that several pathogenic Parkin variants represent promising targets to stratify patients for genotype-specific drug design.


Genome ◽  
2017 ◽  
Vol 60 (1) ◽  
pp. 46-54 ◽  
Author(s):  
Eric M. Merzetti ◽  
Lindsay A. Dolomount ◽  
Brian E. Staveley

Parkinsonian-pyramidal syndrome (PPS) is an early onset form of Parkinson’s disease (PD) that shows degeneration of the extrapyramidal region of the brain to result in a severe form of PD. The toxic protein build-up has been implicated in the onset of PPS. Protein removal is mediated by an intracellular proteasome complex: an E3 ubiquitin ligase, the targeting component, is essential for function. FBXO7 encodes the F-box component of the SCF E3 ubiquitin ligase linked to familial forms of PPS. The Drosophila melanogaster homologue nutcracker (ntc) and a binding partner, PI31, have been shown to be active in proteasome function. We show that altered expression of either ntc or PI31 in dopaminergic neurons leads to a decrease in longevity and locomotor ability, phenotypes both associated with models of PD. Furthermore, expression of ntc-RNAi in an established α-synuclein-dependent model of PD rescues the phenotypes of diminished longevity and locomotor control.


2021 ◽  
Author(s):  
Ernesto Estrada

Abstract Background : Extensive extrapulmonary damages in a dozen of organs/systems, including the central nervous system (CNS), are reported in patients of the coronavirus disease 2019 (COVID-19). Three cases of Parkinson's disease (PD) have been reported as a direct consequence of COVID-19. In spite of the scarce data for establishing a definitive link between COVID-19 and PD some hypothesis have been proposed to explain the cases reported. They, however, do not fit well with the clinical findings reported for COVID-19 patients in general and for the PD cases reported in particular. Given the importance of this potential connection we present here a molecular-level mechanism that explain well these findings and will serve to explore the potential CNS damage in COVID-19 patients. Methods : A model explaining the cascade effects from COVID-19 to CNS is developed by using bioinformatic tools. It includes the post-translational modification of host proteins in the lungs by viral proteins, the transport of modified host proteins via exosomes out the lungs, and the disruption of protein-protein interaction in the CNS by these modified host proteins. Results : We found 44 proteins significantly expressed in the CNS which are associated with PD and whose interactions can be perturbed by 24 host proteins significantly expressed in the lungs. These 24 perturbators are found to interact with viral proteins and to form part of the cargoes of exosomes in human tissues. The joint set of perturbators and PD-vulnerable proteins form a tightly connected network with significantly more connections than expected by selecting a random cluster of proteins of similar size from the human proteome. Conclusions : The molecular-level mechanism presented here provides several routes for the cascading of effects from the lungs of COVID-19 patients to PD. In particular, the disruption of autophagy/ubiquitination processes appears as an important mechanism that triggers the generation of large amounts of exosomes containing perturbators in their cargo, which would insult several PD-vulnerable proteins, potentially triggering Parkinsonism in COVID-19 patients.


Author(s):  
Nitu Dogra ◽  
Ruchi Jakhmola Mani ◽  
Deepshikha Pande Katare

Background: Tremor is one of the most noticeable features, which occurs during the early stages of Parkinson’s disease (PD). It is one of the major pathological hallmarks and does not have any interpreted mechanism. In this study we have framed a hypothesis and deciphered protein-protein interactions between the proteins involved in impairment in sodium and calcium ion channels and thus cause synaptic plasticity leading to a tremor. Methods: Literature mining for retrieval of proteins was done using Science Direct, PubMed Central, SciELO and JSTOR databases. A well thought approach was used and a list of differentially expressed proteins in PD was collected from different sources. A total of 71 proteins were retrieved and a protein interaction network was constructed between them by using Cytoscape.v.3.7. The network was further analysed using BiNGO plugin for retrieval of overrepresented biological processes in Tremor-PD datasets. Hub nodes were also generated in the network. Results: The Tremor-PD pathway was deciphered which demonstrates the cascade of protein interactions that might lead to tremors in PD. Major proteins involved were LRRK2, TUBA1A, TRAF6, HSPA5, ADORA2A, DRD1, DRD2, SNCA, ADCY5, TH etc. Conclusion: In the current study it is predicted that ADORA2A and DRD1/DRD2 are equally contributing to the progression of disease by inhibiting the activity of adenylyl cyclase and thereby increases the permeability of the blood brain barrier causing an influx of neurotransmitters and together they alter the level of dopamine in the brain which eventually leads to tremor.


2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Valérie Drouet ◽  
Suzanne Lesage

Synaptojanin 1 (SYNJ1) is a phosphoinositide phosphatase highly expressed in nerve terminals. Its two phosphatase domains dephosphorylate phosphoinositides present in membranes, while its proline-rich domain directs protein-protein interactions with synaptic components, leading to efficient recycling of synaptic vesicles in neurons. Triplication of SYNJ1 in Down’s syndrome is responsible for higher level of phosphoinositides, enlarged endosomes, and learning deficits. SYNJ1 downregulation in Alzheimer’s disease models is protective towards amyloid-beta peptide (Aβ) toxicity. One missense mutation in one of SYNJ1 functional domains was recently incriminated in an autosomal recessive form of early-onset Parkinson’s disease (PD). In the third decade of life, these patients develop progressive Parkinsonism with bradykinesia, dystonia, and variable atypical symptoms such as cognitive decline, seizures, and eyelid apraxia. The identification of this new gene, together with the fact that most of the known PD proteins play a role in synaptic vesicle recycling and lipid metabolism, points out that synaptic maintenance is a key player in PD pathological mechanisms. Studying PD genes as a network regulating synaptic activity could bring insight into understanding the neuropathological processes of PD and help identify new genes at fault in this devastating disorder.


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