scholarly journals Rab GTPases in Parkinson’s disease: a primer

2021 ◽  
Author(s):  
Antonio Jesús Lara Ordóñez ◽  
Rachel Fasiczka ◽  
Yahaira Naaldijk ◽  
Sabine Hilfiker

Abstract Parkinson’s disease is a prominent and debilitating movement disorder characterized by the death of vulnerable neurons which share a set of structural and physiological properties. Over the recent years, increasing evidence indicates that Rab GTPases can directly as well as indirectly contribute to the cellular alterations leading to PD. Rab GTPases are master regulators of intracellular membrane trafficking events, and alterations in certain membrane trafficking steps can be particularly disruptive to vulnerable neurons. Here, we describe current knowledge on the direct links between altered Rab protein function and PD pathomechanisms.

2018 ◽  
Vol 46 (6) ◽  
pp. 1707-1712 ◽  
Author(s):  
Suzanne R. Pfeffer

Leucine-rich repeat kinase 2 (LRRK2) is mutated in familial Parkinson's disease, and pathogenic mutations activate the kinase activity. A tour de force screen by Mann and Alessi and co-workers identified a subset of Rab GTPases as bona fide LRRK2 substrates. Rab GTPases are master regulators of membrane trafficking and this short review will summarize what we know about the connection between LRRK2 and this family of regulatory proteins. While, in most cases, Rab GTPase phosphorylation is predicted to interfere with Rab protein function, the discovery of proteins that show preferential binding to phosphorylated Rabs suggests that more complex interactions may also contribute to mutant LRRK2-mediated pathology.


2000 ◽  
Vol 113 (2) ◽  
pp. 183-192 ◽  
Author(s):  
J. Somsel Rodman ◽  
A. Wandinger-Ness

Endocytosis is characterized by vesicular transport along numerous pathways. Common steps in each pathway include membrane budding to form vesicles, transport to a particular destination, and ultimately docking and fusion with the target membrane. Specificity of vesicle targeting is rendered in part by associated Rab GTPases. This review summarizes current knowledge about Rab GTPase functions in the endocytic pathways and provides insight into the regulation of Rab GTPase activity and mechanisms of Rab protein function. Functional assays have identified some Rab proteins that operate on individual pathways, but Rab proteins in several pathways remain controversial or have not been identified. Control of Rab GTPase activity is exerted through multiple levels of regulation. Significant new information pertaining to Rab protein function in regulating transport has emerged. Remarkably, Rab5 GTPase links budding, cytoskeletal transport and docking/fusion activities. This paradigm will most likely be generally applicable to other Rab GTPase pathways. Together with the cross-talk between different Rab proteins and their effectors, this may provide an integrated system for the general coordination of endocytic pathways to maintain organelle homeostasis.


2020 ◽  
Vol 25 (42) ◽  
pp. 4510-4522 ◽  
Author(s):  
Biancamaria Longoni ◽  
Irene Fasciani ◽  
Shivakumar Kolachalam ◽  
Ilaria Pietrantoni ◽  
Francesco Marampon ◽  
...  

: Exosomes are extracellular vesicles produced by eukaryotic cells that are also found in most biological fluids and tissues. While they were initially thought to act as compartments for removal of cellular debris, they are now recognized as important tools for cell-to-cell communication and for the transfer of pathogens between the cells. They have attracted particular interest in neurodegenerative diseases for their potential role in transferring prion-like proteins between neurons, and in Parkinson’s disease (PD), they have been shown to spread oligomers of α-synuclein in the brain accelerating the progression of this pathology. A potential neuroprotective role of exosomes has also been equally proposed in PD as they could limit the toxicity of α-synuclein by clearing them out of the cells. Exosomes have also attracted considerable attention for use as drug vehicles. Being nonimmunogenic in nature, they provide an unprecedented opportunity to enhance the delivery of incorporated drugs to target cells. In this review, we discuss current knowledge about the potential neurotoxic and neuroprotective role of exosomes and their potential application as drug delivery systems in PD.


Immuno ◽  
2021 ◽  
Vol 1 (2) ◽  
pp. 78-90
Author(s):  
Johannes Burtscher ◽  
Grégoire P. Millet

Like in other neurodegenerative diseases, protein aggregation, mitochondrial dysfunction, oxidative stress and neuroinflammation are hallmarks of Parkinson’s disease (PD). Differentiating characteristics of PD include the central role of α-synuclein in the aggregation pathology, a distinct vulnerability of the striato-nigral system with the related motor symptoms, as well as specific mitochondrial deficits. Which molecular alterations cause neurodegeneration and drive PD pathogenesis is poorly understood. Here, we summarize evidence of the involvement of three interdependent factors in PD and suggest that their interplay is likely a trigger and/or aggravator of PD-related neurodegeneration: hypoxia, acidification and inflammation. We aim to integrate the existing knowledge on the well-established role of inflammation and immunity, the emerging interest in the contribution of hypoxic insults and the rather neglected effects of brain acidification in PD pathogenesis. Their tight association as an important aspect of the disease merits detailed investigation. Consequences of related injuries are discussed in the context of aging and the interaction of different brain cell types, in particular with regard to potential consequences on the vulnerability of dopaminergic neurons in the substantia nigra. A special focus is put on the identification of current knowledge gaps and we emphasize the importance of related insights from other research fields, such as cancer research and immunometabolism, for neurodegeneration research. The highlighted interplay of hypoxia, acidification and inflammation is likely also of relevance for other neurodegenerative diseases, despite disease-specific biochemical and metabolic alterations.


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Hui Yung Chin ◽  
Michael Lardelli ◽  
Lyndsey Collins-Praino ◽  
Karissa Barthelson

AbstractMutation of the gene PARK7 (DJ1) causes monogenic autosomal recessive Parkinson’s disease (PD) in humans. Subsequent alterations of PARK7 protein function lead to mitochondrial dysfunction, a major element in PD pathology. Homozygous mutants for the PARK7-orthologous genes in zebrafish, park7, show changes to gene expression in the oxidative phosphorylation pathway, supporting that disruption of energy production is a key feature of neurodegeneration in PD. Iron is critical for normal mitochondrial function, and we have previously used bioinformatic analysis of IRE-bearing transcripts in brain transcriptomes to find evidence supporting the existence of iron dyshomeostasis in Alzheimer’s disease. Here, we analysed IRE-bearing transcripts in the transcriptome data from homozygous park7−/− mutant zebrafish brains. We found that the set of genes with “high quality” IREs in their 5′ untranslated regions (UTRs, the HQ5′IRE gene set) was significantly altered in these 4-month-old park7−/− brains. However, sets of genes with IREs in their 3′ UTRs appeared unaffected. The effects on HQ5′IRE genes are possibly driven by iron dyshomeostasis and/or oxidative stress, but illuminate the existence of currently unknown mechanisms with differential overall effects on 5′ and 3′ IREs.


Cells ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 283
Author(s):  
Daniel Aghaie Madsen ◽  
Sissel Ida Schmidt ◽  
Morten Blaabjerg ◽  
Morten Meyer

Parkin and α-synuclein are two key proteins involved in the pathophysiology of Parkinson’s disease (PD). Neurotoxic alterations of α-synuclein that lead to the formation of toxic oligomers and fibrils contribute to PD through synaptic dysfunction, mitochondrial impairment, defective endoplasmic reticulum and Golgi function, and nuclear dysfunction. In half of the cases, the recessively inherited early-onset PD is caused by loss of function mutations in the PARK2 gene that encodes the E3-ubiquitin ligase, parkin. Parkin is involved in the clearance of misfolded and aggregated proteins by the ubiquitin-proteasome system and regulates mitophagy and mitochondrial biogenesis. PARK2-related PD is generally thought not to be associated with Lewy body formation although it is a neuropathological hallmark of PD. In this review article, we provide an overview of post-mortem neuropathological examinations of PARK2 patients and present the current knowledge of a functional interaction between parkin and α-synuclein in the regulation of protein aggregates including Lewy bodies. Furthermore, we describe prevailing hypotheses about the formation of intracellular micro-aggregates (synuclein inclusions) that might be more likely than Lewy bodies to occur in PARK2-related PD. This information may inform future studies aiming to unveil primary signaling processes involved in PD and related neurodegenerative disorders.


2009 ◽  
Vol 67 (3b) ◽  
pp. 930-939 ◽  
Author(s):  
Arthur Kummer ◽  
Antonio Lucio Teixeira

Parkinson's disease (PD) is traditionally regarded as a movement disorder. In recent years, however, non-motor symptoms have been considered significant factors of disability at all stages of the illness. Behavioral and psychological symptoms or neuropsychiatric syndromes associated with PD are frequent and may represent a challenge in the management of these patients. They include anxiety, depression, psychosis, sleep, sexual and impulse control disorders, apathy and cognitive dysfunction. Their pathogenesis in PD is complex, involving neurodegenerative, drug-related and psychological mechanisms. We will review the current knowledge of this growing field, also focusing on the management of theses syndromes.


2021 ◽  
Author(s):  
Melissa Scholefield ◽  
Stephanie J. Church ◽  
Jingshu Xu ◽  
Stefano Patassini ◽  
Federico Roncaroli ◽  
...  

Abstract Background: Widespread elevations in brain urea have, in recent years, been reported in certain types of age-related dementia, notably Alzheimer’s disease (AD) and Huntington’s disease (HD). Urea increases in these diseases are substantive, and approximate in magnitude to levels present in uraemic encephalopathy. In AD and HD, elevated urea levels occur across the entire brain, and not only in regions heavily affected by neurodegeneration. However, measurements of brain urea have not hitherto been reported in Parkinson’s disease dementia (PDD), a condition defined by changes in thinking and behaviour in someone with a diagnosis of Parkinson's disease, which shares neuropathological and symptomatic overlap with both AD and HD. This study aims to address this gap in the current knowledge of PDD.Methods: Here we report measurements of tissue urea from nine neuropathologically-confirmed regions of the brain in PDD and post-mortem-delay-matched controls, in regions that included the cerebellum, motor cortex, sensory cortex, hippocampus, substantia nigra, middle temporal gyrus, medulla oblongata, cingulate gyrus, and pons, by applying ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Case-control differences were determined using multiple t-tests followed by correction with 10% false discovery rate.Results: We found urea concentrations to be substantively elevated in all nine regions, the average increase being 3-4-fold. Urea concentrations were remarkably consistent across regions in both cases and controls, with no clear distinction between regions heavily affected by neuronal loss in PDD compared to less severely affected areas. These urea elevations mirror those found in uraemic encephalopathy, where equivalent levels are generally considered to be pathogenic. These urea elevations also reflect those previously reported in AD and HD. Conclusions: Increased urea is a widespread metabolic perturbation in brain metabolism common to PDD, AD, and HD, at levels equal to those seen in uremic encephalopathy. This presents a novel pathogenic mechanism in PDD, which is shared with two other neurodegenerative diseases.


2018 ◽  
Vol 475 (1) ◽  
pp. 185-189 ◽  
Author(s):  
Patrick A. Eyers

The addition of phosphate groups to substrates allows protein kinases to regulate a myriad of biological processes, and contextual analysis of protein-bound phosphate is important for understanding how kinases contribute to physiology and disease. Leucine-rich repeat kinase 2 (LRRK2) is a Ser/Thr kinase linked to familial and sporadic cases of Parkinson's disease (PD). Recent work established that multiple Rab GTPases are physiological substrates of LRRK2, with Rab10 in particular emerging as a human substrate whose site-specific phosphorylation mirrors hyperactive LRRK2 lesions associated with PD. However, current assays to quantify Rab10 phosphorylation are expensive, time-consuming and technically challenging. In back-to-back studies reported in the Biochemical Journal, Alessi and colleagues teamed up with clinical colleagues and collaborators at the Michael J. Fox Foundation (MJFF) for Parkinson's research to develop, and validate, a panel of exquisitely sensitive phospho-specific Rab antibodies. Of particular interest, the monoclonal antibody-designated MJFF-pRAB10 detects phosphorylated Rab 10 on Thr73 in a variety of cells, brain extracts, PD-derived samples and human neutrophils, the latter representing a previously unrecognised biological resource for LRRK2 signalling analysis. In the future, these antibodies could become universal resources in the fight to understand and quantify connections between LRRK2 and Rab proteins, including those associated with clinical PD.


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