scholarly journals Parkin-mediated ubiquitin signalling in aggresome formation and autophagy

2010 ◽  
Vol 38 (1) ◽  
pp. 144-149 ◽  
Author(s):  
Lih-Shen Chin ◽  
James A. Olzmann ◽  
Lian Li
Keyword(s):  
Protein Misfolding ◽  
Current Knowledge ◽  
Ubiquitin Proteasome System ◽  
Misfolded Proteins ◽  
Proteotoxic Stress ◽  
Ubiquitin Proteasome ◽  
Autophagy Pathway ◽  
Aggresome Formation ◽  
Protein Misfolding And Aggregation ◽  
Cellular Defence

Understanding how cells handle and dispose of misfolded proteins is of paramount importance because protein misfolding and aggregation underlie the pathogenesis of many neurodegenerative disorders, including PD (Parkinson's disease) and Alzheimer's disease. In addition to the ubiquitin–proteasome system, the aggresome–autophagy pathway has emerged as another crucial cellular defence system against toxic build-up of misfolded proteins. In contrast with basal autophagy that mediates non-selective, bulk clearance of misfolded proteins along with normal cellular proteins and organelles, the aggresome–autophagy pathway is increasingly recognized as a specialized type of induced autophagy that mediates selective clearance of misfolded and aggregated proteins under the conditions of proteotoxic stress. Recent evidence implicates PD-linked E3 ligase parkin as a key regulator of the aggresome–autophagy pathway and indicates a signalling role for Lys63-linked polyubiquitination in the regulation of aggresome formation and autophagy. The present review summarizes the current knowledge of the aggresome–autophagy pathway, its regulation by parkin-mediated Lys63-linked polyubiquitination, and its dysfunction in neurodegenerative diseases.

Protein Quality Control Degradation in the Nucleus

2018 ◽  
Vol 87 (1) ◽  
pp. 725-749 ◽  
Author(s):  
Charisma Enam ◽  
Yifat Geffen ◽  
Tommer Ravid ◽  
Richard G. Gardner
Keyword(s):  
Quality Control ◽  
Protein Misfolding ◽  
Protein Quality ◽  
Current Knowledge ◽  
Protein Quality Control ◽  
Ubiquitin Proteasome System ◽  
Misfolded Proteins ◽  
Cellular Processes ◽  
Human Disorders ◽  
Protein Misfolding And Aggregation

Nuclear proteins participate in diverse cellular processes, many of which are essential for cell survival and viability. To maintain optimal nuclear physiology, the cell employs the ubiquitin-proteasome system to eliminate damaged and misfolded proteins in the nucleus that could otherwise harm the cell. In this review, we highlight the current knowledge about the major ubiquitin-protein ligases involved in protein quality control degradation (PQCD) in the nucleus and how they orchestrate their functions to eliminate misfolded proteins in different nuclear subcompartments. Many human disorders are causally linked to protein misfolding in the nucleus, hence we discuss major concepts that still need to be clarified to better understand the basis of the nuclear misfolded proteins’ toxic effects. Additionally, we touch upon potential strategies for manipulating nuclear PQCD pathways to ameliorate diseases associated with protein misfolding and aggregation in the nucleus.

Neurodegenerative Diseases as Protein Misfolding Disorders

2016 ◽  
Author(s):  
Tomohiro Nakamura ◽  
Stuart A. Lipton
Keyword(s):  
Quality Control ◽  
Neurodegenerative Diseases ◽  
Protein Misfolding ◽  
Protein Quality ◽  
Protein S ◽  
Ubiquitin Proteasome System ◽  
Misfolded Proteins ◽  
Redox Stress ◽  
Chemical Mechanisms ◽  
Ubiquitin Proteasome

Neurodegenerative diseases (NDDs) often represent disorders of protein folding. Rather than large aggregates, recent evidence suggests that soluble oligomers of misfolded proteins are the most neurotoxic species. Emerging evidence points to small, soluble oligomers of misfolded proteins as the cause of synaptic dysfunction and loss, the major pathological correlate to disease progression in many NDDs including Alzheimer’s disease. The protein quality control machinery of the cell, which includes molecular chaperones as found in the endoplasmic reticulum (ER), the ubiquitin-proteasome system (UPS), and various forms of autophagy, can counterbalance the accumulation of misfolded proteins to some extent. Their ability to eliminate the neurotoxic effects of misfolded proteins, however, declines with age. A plausible explanation for the age-dependent deterioration of the quality control machinery involves compromise of these systems by excessive generation of reactive oxygen species (ROS), such as superoxide anion (O2-), and reactive nitrogen species (RNS), such as nitric oxide (NO). The resulting redox stress contributes to the accumulation of misfolded proteins. Here, we focus on aberrantly increased generation of NO-related species since this process appears to accelerate the manifestation of key neuropathological features, including protein misfolding. We review the chemical mechanisms of posttranslational modification by RNS such as protein S-nitrosylation of critical cysteine thiol groups and nitration of tyrosine residues, showing how they contribute to the pathogenesis of NDDs.

scholarly journals The Deubiquitylating Enzyme Ubp12 Regulates Rad23-Dependent Substrate Delivery at the Proteasome

2017 ◽  
Author(s):  
Daniela Gödderz ◽  
Nico P. Dantuma
Keyword(s):  
Dna Repair ◽  
Ubiquitin Proteasome System ◽  
Proteasomal Degradation ◽  
Misfolded Proteins ◽  
Proteotoxic Stress ◽  
Lysine Residues ◽  
Regulatory Link ◽  
Ubiquitin Proteasome ◽  
Summary Statement

AbstractThe consecutive actions of the ubiquitin-selective segregase Cdc48 and the ubiquitin shuttle factor Rad23 result in the delivery of ubiquitylated proteins at the proteasome. Here, we show that the deubiquitylating enzyme Ubp12 interacts with Cdc48 and regulates proteasomal degradation of Rad23-dependent substrates. Overexpression of Ubp12 results in stabilization of Rad23-dependent substrates. We show that Ubp12 removes short ubiquitin chains from the N-terminal ubiquitin-like domain (UbL) of Rad23. Preventing ubiquitylation of Rad23 by substitution of lysine residues within the UbL domain, Rad23UbLK0, does not affect the non-proteolytic role of Rad23 in DNA repair but causes an increase in ubiquitylated cargo bound to the UBA2 domains of Rad23 and recapitulates the stabilization of Rad23-dependent substrates observed upon overexpression of Ubp12. Expression of Rad23UbLK0or overexpression of Ubp12 impairs the ability of yeast to cope with proteotoxic stress consistent with inefficient clearance of misfolded proteins by the ubiquitin/proteasome system. Our data suggest that ubiquitylation of Rad23 plays a stimulatory role in facilitating the transfer of ubiquitylated substrates to the proteasome.Summary statementUbiquitylation of a ubiquitin shuttle factor regulates the delivery of substrates at the proteasome, uncovering a novel regulatory link between ubiquitin and proteasomal degradation.

Proteostasis regulation by the ubiquitin system

2016 ◽  
Vol 60 (2) ◽  
pp. 143-151 ◽  
Author(s):  
John S. Bett
Keyword(s):  
Protein Misfolding ◽  
Amyotrophic Lateral Sclerosis Patient ◽  
Ubiquitin Proteasome System ◽  
Cellular Protein ◽  
Ubiquitin System ◽  
Ubiquitin Proteasome ◽  
Ad Alzheimer’S Disease ◽  
Cellular Phenotypes ◽  
Protein Misfolding And Aggregation ◽  
Lateral Sclerosis

Cells have developed an evolutionary obligation to survey and maintain proteome fidelity and avoid the possible toxic consequences of protein misfolding and aggregation. Disturbances to protein homoeostasis (proteostasis) can result in severe cellular phenotypes and are closely linked with the accumulation of microscopically visible deposits of aggregated proteins. These include inclusion bodies found in AD (Alzheimer's disease), HD (Huntington's disease) and ALS (amyotrophic lateral sclerosis) patient neurons. Protein aggregation is intimately linked with the ubiquitin and ubiquitin-like post-translational modifier system, which manages cellular protein folding stress and promotes the restoration of proteostasis. This is achieved in large part through the action of the UPS (ubiquitin–proteasome system), which is responsible for directing the proteasomal destruction of misfolded and damaged proteins tagged with ubiquitin chains. There are other less well understood ways in which ubiquitin family members can help to maintain proteostasis that complement, but are independent of, the UPS. This article discusses our current understanding of how the ubiquitin family regulates the protein misfolding pathways that threaten proteome fidelity, and how this is achieved by the key players in this process.

scholarly journals PDE1 inhibition facilitates proteasomal degradation of misfolded proteins and protects against cardiac proteinopathy

2019 ◽  
Vol 5 (5) ◽  
pp. eaaw5870 ◽  
Author(s):  
Hanming Zhang ◽  
Bo Pan ◽  
Penglong Wu ◽  
Nirmal Parajuli ◽  
Mark D. Rekhter ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Ubiquitin Proteasome System ◽  
Proteasomal Degradation ◽  
Current Treatment ◽  
Misfolded Proteins ◽  
Dependent Protein Kinase ◽  
Selective Degradation ◽  
Proteotoxic Stress ◽  
Ubiquitin Proteasome ◽  
Dependent Protein

No current treatment targets cardiac proteotoxicity or can reduce mortality of heart failure (HF) with preserved ejection fraction (HFpEF). Selective degradation of misfolded proteins by the ubiquitin-proteasome system (UPS) is vital to the cell. Proteasome impairment contributes to HF. Activation of cAMP-dependent protein kinase (PKA) or cGMP-dependent protein kinase (PKG) facilitates proteasome functioning. Phosphodiesterase 1 (PDE1) hydrolyzes both cyclic nucleotides and accounts for most PDE activities in human myocardium. We report that PDE1 inhibition (IC86430) increases myocardial 26S proteasome activities and UPS proteolytic function in mice. Mice with CryABR120G-based proteinopathy develop HFpEF and show increased myocardial PDE1A expression. PDE1 inhibition markedly attenuates HFpEF, improves mouse survival, increases PKA-mediated proteasome phosphorylation, and reduces myocardial misfolded CryAB. Therefore, PDE1 inhibition induces PKA- and PKG-mediated promotion of proteasomal degradation of misfolded proteins and treats HFpEF caused by CryABR120G, representing a potentially new therapeutic strategy for HFpEF and heart disease with increased proteotoxic stress.

scholarly journals The CP110-CEP97-CEP290 module orchestrates a centriolar satellite dependent response to proteotoxic stress

2020 ◽  
Author(s):  
Suzanna L. Prosser ◽  
Johnny Tkach ◽  
Ladan Gheiratmand ◽  
Ciaran G. Morrison ◽  
Laurence Pelletier
Keyword(s):  
Quantitative Analysis ◽  
Ubiquitin Proteasome System ◽  
Mutant Huntingtin ◽  
Cellular Processes ◽  
Proteotoxic Stress ◽  
Human Disorders ◽  
Ubiquitin Proteasome ◽  
Microscopy Analysis ◽  
Aggresome Formation ◽  
Centrosomal Proteins

ABSTRACTProtein degradation at the centrosome, the primary microtubule organizing centre of the cell, is critical to a myriad of cellular processes. Perturbation of the ubiquitin proteasome system causes the formation of an inclusion, or aggresome, at the centrosome. By systematic microscopy analysis, we have placed a subset of centrosomal proteins within the aggresome. Centriolar satellites, proteinaceous granules found in the vicinity of centrosomes, also became incorporated into this structure. Through high-resolution quantitative analysis, we have defined aggresome assembly at the centrosome, demonstrating a requirement for satellites in this process. Furthermore, a module consisting of CP110-CEP97-CEP290 was required to recruit aggresome components early in the pathway and senescent cells were defective in aggresome formation due to limiting amounts of CP110. Finally, satellites and the CP110-CEP97-CEP290 module were required for the aggregation of mutant huntingtin. The accumulation of protein aggregates is central to the pathology of a range of human disorders. These data thereby reveal new roles for CP110, its interactors, and centriolar satellites in controlling cellular proteostasis and the aggregation of disease relevant proteins.

Protein misfolding and aggregation in neurodegenerative diseases: a review of pathogeneses, novel detection strategies, and potential therapeutics

2019 ◽  
Vol 30 (4) ◽  
pp. 339-358 ◽  
Author(s):  
Jason Gandhi ◽  
Anthony C. Antonelli ◽  
Adil Afridi ◽  
Sohrab Vatsia ◽  
Gunjan Joshi ◽  
...  
Keyword(s):  
Protein Folding ◽  
Neurodegenerative Diseases ◽  
Protein Misfolding ◽  
Ubiquitin Proteasome System ◽  
Transmissible Spongiform Encephalopathies ◽  
Stable Conformation ◽  
Spongiform Encephalopathies ◽  
Folding Process ◽  
Ubiquitin Proteasome ◽  
Protein Misfolding And Aggregation

Abstract Protein folding is a complex, multisystem process characterized by heavy molecular and cellular footprints. Chaperone machinery enables proper protein folding and stable conformation. Other pathways concomitant with the protein folding process include transcription, translation, post-translational modifications, degradation through the ubiquitin-proteasome system, and autophagy. As such, the folding process can go awry in several different ways. The pathogenic basis behind most neurodegenerative diseases is that the disruption of protein homeostasis (i.e. proteostasis) at any level will eventually lead to protein misfolding. Misfolded proteins often aggregate and accumulate to trigger neurotoxicity through cellular stress pathways and consequently cause neurodegenerative diseases. The manifestation of a disease is usually dependent on the specific brain region that the neurotoxicity affects. Neurodegenerative diseases are age-associated, and their incidence is expected to rise as humans continue to live longer and pursue a greater life expectancy. We presently review the sequelae of protein misfolding and aggregation, as well as the role of these phenomena in several neurodegenerative diseases including Alzheimer’s disease, Huntington’s disease, amyotrophic lateral sclerosis, Parkinson’s disease, transmissible spongiform encephalopathies, and spinocerebellar ataxia. Strategies for treatment and therapy are also conferred with respect to impairing, inhibiting, or reversing protein misfolding.

scholarly journals Co-Chaperones in Targeting and Delivery of Misfolded Proteins to the 26S Proteasome

Biomolecules ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1141 ◽  
Author(s):  
Amanda B. Abildgaard ◽  
Sarah K. Gersing ◽  
Sven Larsen-Ledet ◽  
Sofie V. Nielsen ◽  
Amelie Stein ◽  
...  
Keyword(s):  
Protein Quality ◽  
Current Knowledge ◽  
Ubiquitin Proteasome System ◽  
26S Proteasome ◽  
Misfolded Proteins ◽  
Nucleotide Exchange ◽  
Nucleotide Exchange Factors ◽  
Ubiquitin Proteasome ◽  
Underlying Mechanisms ◽  
The Individual

Protein homeostasis (proteostasis) is essential for the cell and is maintained by a highly conserved protein quality control (PQC) system, which triages newly synthesized, mislocalized and misfolded proteins. The ubiquitin-proteasome system (UPS), molecular chaperones, and co-chaperones are vital PQC elements that work together to facilitate degradation of misfolded and toxic protein species through the 26S proteasome. However, the underlying mechanisms are complex and remain partly unclear. Here, we provide an overview of the current knowledge on the co-chaperones that directly take part in targeting and delivery of PQC substrates for degradation. While J-domain proteins (JDPs) target substrates for the heat shock protein 70 (HSP70) chaperones, nucleotide-exchange factors (NEFs) deliver HSP70-bound substrates to the proteasome. So far, three NEFs have been established in proteasomal delivery: HSP110 and the ubiquitin-like (UBL) domain proteins BAG-1 and BAG-6, the latter acting as a chaperone itself and carrying its substrates directly to the proteasome. A better understanding of the individual delivery pathways will improve our ability to regulate the triage, and thus regulate the fate of aberrant proteins involved in cell stress and disease, examples of which are given throughout the review.

scholarly journals Nuclear Ubiquitin-Proteasome Pathways in Proteostasis Maintenance

Biomolecules ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 54
Author(s):  
Dina Franić ◽  
Klara Zubčić ◽  
Mirta Boban
Keyword(s):  
Quality Control ◽  
Protein Misfolding ◽  
Protein Quality ◽  
Protein Quality Control ◽  
Ubiquitin Proteasome System ◽  
Cytoplasmic Proteins ◽  
Ubiquitin Proteasome ◽  
A Cell ◽  
Protein Misfolding And Aggregation ◽  
Order Complexes

Protein homeostasis, or proteostasis, is crucial for the functioning of a cell, as proteins that are mislocalized, present in excessive amounts, or aberrant due to misfolding or other type of damage can be harmful. Proteostasis includes attaining the correct protein structure, localization, and the formation of higher order complexes, and well as the appropriate protein concentrations. Consequences of proteostasis imbalance are evident in a range of neurodegenerative diseases characterized by protein misfolding and aggregation, such as Alzheimer’s, Parkinson’s, and amyotrophic lateral sclerosis. To protect the cell from the accumulation of aberrant proteins, a network of protein quality control (PQC) pathways identifies the substrates and direct them towards refolding or elimination via regulated protein degradation. The main pathway for degradation of misfolded proteins is the ubiquitin-proteasome system. PQC pathways have been first described in the cytoplasm and the endoplasmic reticulum, however, accumulating evidence indicates that the nucleus is an important PQC compartment for ubiquitination and proteasomal degradation of not only nuclear, but also cytoplasmic proteins. In this review, we summarize the nuclear ubiquitin-proteasome pathways involved in proteostasis maintenance in yeast, focusing on inner nuclear membrane-associated degradation (INMAD) and San1-mediated protein quality control.

scholarly journals Interaction between Parkin and α-Synuclein in PARK2-Mediated Parkinson’s Disease

Cells ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 283
Author(s):  
Daniel Aghaie Madsen ◽  
Sissel Ida Schmidt ◽  
Morten Blaabjerg ◽  
Morten Meyer
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Ubiquitin Ligase ◽  
Current Knowledge ◽  
Lewy Bodies ◽  
Ubiquitin Proteasome System ◽  
Loss Of Function ◽  
Functional Interaction ◽  
Future Studies ◽  
Ubiquitin Proteasome

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.

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