scholarly journals Synaptojanin 1 Mutation in Parkinson’s Disease Brings Further Insight into the Neuropathological Mechanisms

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Valérie Drouet ◽  
Suzanne Lesage
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Protein Interactions ◽  
Synaptic Activity ◽  
Atypical Symptoms ◽  
Rich Domain ◽  
New Genes ◽  
Phosphoinositide Phosphatase ◽  
Synaptojanin 1 ◽  
Insight Into

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.

scholarly journals Absence of Sac2/INPP5F enhances the phenotype of a Parkinson’s disease mutation of synaptojanin 1

2020 ◽  
Vol 117 (22) ◽  
pp. 12428-12434 ◽  
Author(s):  
Mian Cao ◽  
Daehun Park ◽  
Yumei Wu ◽  
Pietro De Camilli
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Association Studies ◽  
Genome Wide Association Studies ◽  
Gene Encoding ◽  
Phosphatase Domain ◽  
Inositol Phosphatase ◽  
Phosphoinositide Phosphatase ◽  
Abnormal Accumulation ◽  
Synaptojanin 1

Numerous genes whose mutations cause, or increase the risk of, Parkinson’s disease (PD) have been identified. An inactivating mutation (R258Q) in the Sac inositol phosphatase domain of synaptojanin 1 (SJ1/PARK20), a phosphoinositide phosphatase implicated in synaptic vesicle recycling, results in PD. The gene encoding Sac2/INPP5F, another Sac domain-containing protein, is located within a PD risk locus identified by genome-wide association studies. Knock-In mice carrying the SJ1 patient mutation (SJ1RQKI) exhibit PD features, while Sac2 knockout mice (Sac2KO) do not have obvious neurologic defects. We report a “synthetic” effect of the SJ1 mutation and the KO of Sac2 in mice. Most mice with both mutations died perinatally. The occasional survivors had stunted growth, died within 3 wk, and showed abnormalities of striatal dopaminergic nerve terminals at an earlier stage than SJ1RQKI mice. The abnormal accumulation of endocytic factors observed at synapses of cultured SJ1RQKI neurons was more severe in double-mutant neurons. Our results suggest that SJ1 and Sac2 have partially overlapping functions and are consistent with a potential role of Sac2 as a PD risk gene.

scholarly journals Deciphering the activation of the E3 ubiquitin ligase parkin

2014 ◽  
Vol 70 (a1) ◽  
pp. C836-C836
Author(s):  
Véronique Sauvé ◽  
Kalle Gehring
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Ubiquitin Ligase ◽  
Protein Interactions ◽  
E3 Ubiquitin Ligase ◽  
Intramolecular Interactions ◽  
Protein Protein Interactions ◽  
Post Translational Modification ◽  
Catalytic Cysteine ◽  
Insight Into

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.

scholarly journals Absence of Sac2/INPP5F enhances the phenotype of a Parkinson’s disease mutation of synaptojanin 1

2020 ◽  
Author(s):  
Mian Cao ◽  
Daehun Park ◽  
Yumei Wu ◽  
Pietro De Camilli
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Gene Encoding ◽  
Phosphatase Domain ◽  
Stunted Growth ◽  
Inositol Phosphatase ◽  
Vesicle Recycling ◽  
Phosphoinositide Phosphatase ◽  
Abnormal Accumulation ◽  
Synaptojanin 1

AbstractMany genes whose mutations cause, or increase the risk of, Parkinson’s disease (PD) have been identified. An inactivating mutation (R258Q) in the Sac inositol phosphatase domain of synaptojanin 1 (SJ1/PARK20), a phosphoinositide phosphatase implicated in synaptic vesicle recycling, results in PD. The gene encoding Sac2/INPP5F, another Sac domain containing protein, was identified as a PD risk locus by GWAS. Knock-In mice carrying the SJ1 patient mutation (SJ1RQKI) exhibit PD features, while Sac2 knockout mice (Sac2KO) do not have obvious neurological defects. We report a “synthetic” effect of the SJ1 mutation and the KO of Sac2 in mice. Most mice with both mutations died perinatally. The occasional survivors had stunted growth, died within 3 weeks, and showed abnormalities of striatal dopaminergic nerve terminals at an earlier stage than SJ1RQKI mice. The abnormal accumulation of endocytic factors observed at synapses of cultured SJ1RQKI neurons was more severe in double mutant. Our results suggest that SJ1 and Sac2 have partially overlapping functions and are consistent with a potential role of Sac2 as a PD risk gene.

scholarly journals Interactions of COMT and ALDH2 Genetic Polymorphisms on Symptoms of Parkinson’s Disease

2021 ◽  
Vol 11 (3) ◽  
pp. 361
Author(s):  
Rwei-Ling Yu ◽  
Shao-Ching Tu ◽  
Ruey-Meei Wu ◽  
Pei-An Lu ◽  
Chun-Hsiang Tan
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Detrimental Effect ◽  
Personal Hygiene ◽  
Nucleotide Polymorphisms ◽  
Monoamine Neurotransmitters ◽  
Single Nucleotide ◽  
Detrimental Impact ◽  
Reduced Activity ◽  
Insight Into

(1) Background: Monoamine neurotransmitters play essential roles in the normal functioning of our nervous system. However, the metabolism of monoamine neurotransmitters is accompanied by the production of neurotoxic metabolites, and inefficient removal of the metabolites has been suggested to cause neurodegeneration. (2) Methods: To examine the effect of reduced activity of catechol-O-methyltransferase (COMT) and aldehyde dehydrogenase 2 (ALDH2) conferred by single nucleotide polymorphisms COMT rs4680(A) and ALDH2 rs671(A) on the symptoms of patients with Parkinson’s disease (PD), a total of 114 PD patients were recruited cross-sectionally and received genotyping for rs4680 and rs671 along with MDS-UPDRS evaluation. (3) Results: We found that patients carrying rs4680(A) had more severe bradykinesia in the upper extremity and rest tremor. Besides, patients carrying rs671(A) had more difficulty maintaining personal hygiene, while patients with genotype rs671(GG) had higher scores in the item “depressed mood.” More importantly, we found the effect of rs4680 to be moderated by rs671 SNP for the symptom of “hand movements.” The detrimental impact of rs4680(A) is more pronounced in the presence of genotype rs671(GG). (4) Conclusions: This study facilitates a deeper understanding of the detrimental effect of reduced activity of COMT and ALDH2 conferred by genetic variation and provides novel insight into the interactions between enzymes metabolizing monoamine neurotransmitters in the pathogenesis of PD.

scholarly journals Cascading from SARS-CoV-2 to Parkinson’s Disease through Protein-Protein Interactions

Viruses ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 897
Author(s):  
Ernesto Estrada
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Protein Interactions ◽  
Molecular Level ◽  
Direct Consequence ◽  
Viral Proteins ◽  
Clinical Findings ◽  
Post Translational Modification ◽  
Host Proteins ◽  
Bioinformatic Tools

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.

scholarly journals A selective effect of dopamine on information-seeking

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Valentina Vellani ◽  
Lianne P de Vries ◽  
Anne Gaule ◽  
Tali Sharot
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Information Seeking ◽  
Selective Effect ◽  
Reward Seeking ◽  
The Impact ◽  
The Brain ◽  
Insight Into ◽  
Primary Reward

Humans are motivated to seek information from their environment. How the brain motivates this behavior is unknown. One speculation is that the brain employs neuromodulatory systems implicated in primary reward-seeking, in particular dopamine, to instruct information-seeking. However, there has been no causal test for the role of dopamine in information-seeking. Here, we show that administration of a drug that enhances dopamine function (dihydroxy-L-phenylalanine; L-DOPA) reduces the impact of valence on information-seeking. Specifically, while participants under Placebo sought more information about potential gains than losses, under L-DOPA this difference was not observed. The results provide new insight into the neurobiology of information-seeking and generates the prediction that abnormal dopaminergic function (such as in Parkinson’s disease) will result in valence-dependent changes to information-seeking.

scholarly journals Pilot Study of Mindfulness Training on the Self-Awareness of Motor Symptoms in Parkinson’s Disease – A Randomized Controlled Trial

2021 ◽  
Vol 12 ◽  
Author(s):  
Timo Marcel Buchwitz ◽  
Franziska Maier ◽  
Andrea Greuel ◽  
Franziska Thieken ◽  
Kenan Steidel ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Control Group ◽  
Motor Symptoms ◽  
Self Awareness ◽  
Disease Symptoms ◽  
Waitlist Control ◽  
Sleeping Problems ◽  
Waitlist Control Group ◽  
Insight Into

Objective: This study aims to evaluate feasibility and effects of a newly developed mindfulness intervention tailored to specific needs of patients with Parkinson’s disease (PD).Background: The phenomenon of impaired self-awareness of motor symptoms (ISAm) in PD might be reduced by increasing patients’ mindfulness. A PD-specific mindfulness intervention has been developed and evaluated as a potential treatment option: IPSUM (“Insight into Parkinson’s Disease Symptoms by using Mindfulness”).Methods: IPSUM’s effectiveness is evaluated by comparing an intervention with a waitlist-control group. Applying a pre-post design, patients were assessed before, directly after and 8weeks after treatment. The primary outcome was the change in a quantitative ISAm score from baseline to post-assessment. Secondary outcome measures were PD-related affective changes and neuropsychological test performance. Feasibility was evaluated via feedback forms.Results: In total, 30 non-depressed and non-demented PD patients were included (intervention: n=14, waitlist-control: n=16). ISAm score did not change significantly, but the training group showed greater performance in sustained attention and language tasks over time. Additional changes included greater mindfulness as well as less sleeping problems and anxiety. Cognitive disturbances, apathy, and sleeping problems worsened only in the waitlist-control group. Patients’ feedback regarding the training concept and material was excellent.Conclusion: Insight into Parkinson’s Disease Symptoms by using Mindfulness has not been capable of reducing ISAm in PD patients but appears to be a feasible and effective concept to, among others, support mental health in the mid-term. It has to be noted though that the study was stopped beforehand because of the SARS CoV-2 pandemic. The lack of findings might therefore be caused by a lack of statistical power. The need for further research to better understand the mechanisms of ISAm and its connection to mindfulness in PD is highlighted.

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