scholarly journals The Effect of Dysfunctional Ubiquitin Enzymes in the Pathogenesis of Most Common Diseases

2020 ◽  
Vol 21 (17) ◽  
pp. 6335 ◽  
Author(s):  
Gizem Celebi ◽  
Hale Kesim ◽  
Ebru Ozer ◽  
Ozlem Kutlu

Ubiquitination is a multi-step enzymatic process that involves the marking of a substrate protein by bonding a ubiquitin and protein for proteolytic degradation mainly via the ubiquitin–proteasome system (UPS). The process is regulated by three main types of enzymes, namely ubiquitin-activating enzymes (E1), ubiquitin-conjugating enzymes (E2), and ubiquitin ligases (E3). Under physiological conditions, ubiquitination is highly reversible reaction, and deubiquitinases or deubiquitinating enzymes (DUBs) can reverse the effect of E3 ligases by the removal of ubiquitin from substrate proteins, thus maintaining the protein quality control and homeostasis in the cell. The dysfunction or dysregulation of these multi-step reactions is closely related to pathogenic conditions; therefore, understanding the role of ubiquitination in diseases is highly valuable for therapeutic approaches. In this review, we first provide an overview of the molecular mechanism of ubiquitination and UPS; then, we attempt to summarize the most common diseases affecting the dysfunction or dysregulation of these mechanisms.

Author(s):  
Xu Zhou ◽  
Xiongjin Chen ◽  
Tingting Hong ◽  
Miaoping Zhang ◽  
Yujie Cai ◽  
...  

AbstractThe tetrapeptide repeat domain 3 (TTC3) gene falls within Down's syndrome (DS) critical region. Cognitive impairment is a common phenotype of DS and Alzheimer’s disease (AD), and overexpression of TTC3 can accelerate cognitive decline, but the specific mechanism is unknown. The TTC3-mediated protein quality control (PQC) mechanism, similar to the PQC system, is divided into three parts: it acts as a cochaperone to assist proteins in folding correctly; it acts as an E3 ubiquitin ligase (E3s) involved in protein degradation processes through the ubiquitin–proteasome system (UPS); and it may also eventually cause autophagy by affecting mitochondrial function. Thus, this article reviews the research progress on the structure, function, and metabolism of TTC3, including the recent research progress on TTC3 in DS and AD; the role of TTC3 in cognitive impairment through PQC in combination with the abovementioned attributes of TTC3; and the potential targets of TTC3 in the treatment of such diseases.


Author(s):  
Yasmeena Akhter ◽  
Jahangir Nabi ◽  
Hinna Hamid ◽  
Nahida Tabassum ◽  
Faheem Hyder Pottoo ◽  
...  

Proteostasis is essential for regulating the integrity of the proteome. Disruption of proteostasis under some rigorous conditions leads to the aggregation and accumulation of misfolded toxic proteins, which plays a central role in the pathogenesis of protein conformational disorders. The protein quality control (PQC) system serves as a multi-level security system to shield cells from abnormal proteins. The intrinsic PQC systems maintaining proteostasis include the ubiquitin-proteasome system (UPS), chaperon-mediated autophagy (CMA), and autophagy-lysosome pathway (ALP) that serve to target misfolded proteins for unfolding, refolding, or degradation. Alterations of PQC systems in neurons have been implicated in the pathogenesis of various neurodegenerative disorders. This chapter provides an overview of PQC pathways to set a framework for discussion of the role of PQC in neurodegenerative disorders. Additionally, various pharmacological approaches targeting PQC are summarized.


Cancers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1579 ◽  
Author(s):  
Ainsley Mike Antao ◽  
Apoorvi Tyagi ◽  
Kye-Seong Kim ◽  
Suresh Ramakrishna

Since the discovery of the ubiquitin proteasome system (UPS), the roles of ubiquitinating and deubiquitinating enzymes (DUBs) have been widely elucidated. The ubiquitination of proteins regulates many aspects of cellular functions such as protein degradation and localization, and also modifies protein-protein interactions. DUBs cleave the attached ubiquitin moieties from substrates and thereby reverse the process of ubiquitination. The dysregulation of these two paramount pathways has been implicated in numerous diseases, including cancer. Attempts are being made to identify inhibitors of ubiquitin E3 ligases and DUBs that potentially have clinical implications in cancer, making them an important target in the pharmaceutical industry. Therefore, studies in medicine are currently focused on the pharmacological disruption of DUB activity as a rationale to specifically target cancer-causing protein aberrations. Here, we briefly discuss the pathophysiological and physiological roles of DUBs in key cancer-related pathways. We also discuss the clinical applications of promising DUB inhibitors that may contribute to the development of DUBs as key therapeutic targets in the future.


2020 ◽  
Vol 11 (7) ◽  
Author(s):  
Xiaowei Wu ◽  
Qingyu Luo ◽  
Zhihua Liu

Abstract MCL1 is an important antiapoptotic member of the BCL-2 family that is distinguishable from other family members based on its relatively short half-life. Emerging studies have revealed the crucial role of MCL1 in the chemoresistance of cancer cells. The antiapoptotic function of MCL1 makes it a popular therapeutic target, although specific inhibitors have begun to emerge only recently. Notably, emerging studies have reported that several E3 ligases and deubiquitinases modulate MCL1 stability, providing an alternate means of targeting MCL1 activity. In addition, the emergence and development of proteolysis-targeting chimeras, the function of which is based on ubiquitination-mediated degradation, has shown great potential. In this review, we provide an overview of the studies investigating the ubiquitination and deubiquitination of MCL1, summarize the latest evidence regarding the development of therapeutic strategies targeting MCL1 in cancer treatment, and discuss the promising future of targeting MCL1 via the ubiquitin–proteasome system in clinical practice.


2021 ◽  
Author(s):  
Lucie M. Wolf ◽  
Annika M. Lambert ◽  
Julie Haenlin ◽  
Michael Boutros

WNT signalling is important for development in all metazoan animals and is associated with various human diseases. The Ubiquitin-Proteasome System (UPS) and regulatory ER-associated degradation (ERAD) have been implicated in the production of WNT proteins. Here, we investigated how the WNT secretory factor EVI/WLS is ubiquitinated, recognised by ERAD components and subsequently removed from the secretory pathway. We performed a focused, immunoblot-based RNAi screen for factors that influence EVI/WLS protein stability. We identified the VCP-binding proteins FAF2 and UBXN4 as novel interaction partners of EVI/WLS and showed that ERLIN2 links EVI/WLS to the ubiquitination machinery. Interestingly, we found in addition that EVI/WLS is ubiquitinated and degraded in cells irrespective of their level of WNT production. This K11, K48, and K63-linked ubiquitination is mediated by the E2 ubiquitin conjugating enzymes UBE2J2, UBE2K, and UBE2N, but independent of the E3 ligases HRD1/SYVN or GP78/AMFR. Taken together, our study identified factors that link the UPS to the WNT secretory pathway and provides mechanistic details on the fate of an endogenous substrate of regulatory ERAD in mammalian cells.


2020 ◽  
Vol 1 ◽  
Author(s):  
Vanessa Machado ◽  
Rui Carvalho ◽  
José João Mendes ◽  
João Botelho

The turnover of intracellular proteins is a highly selective and regulated process. This process is responsible for avoiding injury and irreparable breakdown of cellular constituents. Its impairment disrupts cellular stability, integrity, and homeostasis. The ubiquitin-proteasome system (UPS) is responsible for this programmed degradation of most intracellular proteins. This process involves a cascade of enzymes that involves the ubiquitin conjugation to a target substrate protein, its recognition and degradation by the proteasome. The turn-over of intracellular proteins is a non-stop ubiquitous process that regulates a series of mechanisms, for instance transcription, translation, endocytosis. In addition, proteasome act by releasing peptides that may serve to other purposes, such as antigen presentation in immune actions and enzymatic flagging toward biosynthesis and gluconeogenesis. The role of the UPS impairment in periodontal diseases is gaining growing. This acquaintance might contribute to the development of novel therapeutic applications. Thus, this review focuses on the latest progresses on the role of the UPS and its signaling pathways in Periodontal Medicine. Furthermore, we discuss the potential of UPS-based drugs development to be used in periodontal disease therapy.


2016 ◽  
Vol 473 (22) ◽  
pp. 4083-4101 ◽  
Author(s):  
Mary Iconomou ◽  
Darren N. Saunders

Protein ubiquitylation is a widespread post-translational modification, regulating cellular signalling with many outcomes, such as protein degradation, endocytosis, cell cycle progression, DNA repair and transcription. E3 ligases are a critical component of the ubiquitin proteasome system (UPS), determining the substrate specificity of the cascade by the covalent attachment of ubiquitin to substrate proteins. Currently, there are over 600 putative E3 ligases, but many are poorly characterized, particularly with respect to individual protein substrates. Here, we highlight systematic approaches to identify and validate UPS targets and discuss how they are underpinning rapid advances in our understanding of the biochemistry and biology of the UPS. The integration of novel tools, model systems and methods for target identification is driving significant interest in drug development, targeting various aspects of UPS function and advancing the understanding of a diverse range of disease processes.


2022 ◽  
Vol 2 (1) ◽  
pp. 1-6
Author(s):  
EFTHIMIOS KYRODIMOS ◽  
ARISTEIDIS CHRYSOVERGIS ◽  
NICHOLAS MASTRONIKOLIS ◽  
EVANGELOS TSIAMBAS ◽  
LOUKAS MANAIOS ◽  
...  

Among intra-cellular homeostasis mechanisms, ubiquitination plays a critical role in protein metabolism regulation by degrading proteins via activating a broad spectrum of ubiquitin chains. In fact, ubiquitination and sumoylation signaling pathways are characterized by increased complexity regarding the molecules and their interactions. The Ubiquitin-Proteasome System (Ub-PS) recognizes and targets a broad spectrum of protein substrates. Ubiquitin conjugation modifies each substrate protein determining its biochemical fate (degradation). A major functional activity of Ub-PS is autophagy mechanism regulation. Interestingly, Ub-PS promotesall stages of bulk autophagy (initiation, execution, and termination). Autophagy is a crucial catabolic process that provides protein degradation and for this reason the interaction with Ub-PS is crucial. Furthermore, ubiquitination controls and regulates specific types of protein targets. Ub-PS is also involved in oxidative cellular stress and DNA damage response. Additionally, the functional role of Ub-PS in ribosome machinery regulation seems to be crucial. Concerning carcinogenesis, Ub-PS is involved in malignant disease development and progression by negatively affecting the corresponding TGF-B-, MEEK/MAPK/ERK-JNK- dependent signaling pathways. In the current review article, we describe the role of Ub-PSbiochemicalmodifications and alterations in oral squamous cell carcinoma (OSCC).


2018 ◽  
Vol 217 (6) ◽  
pp. 2019-2032 ◽  
Author(s):  
Rupali Prasad ◽  
Chengchao Xu ◽  
Davis T.W. Ng

Misfolded cytosolic proteins are degraded by the ubiquitin proteasome system through quality control (QC) pathways defined by E3 ubiquitin ligases and associated chaperones. Although they work together as a comprehensive system to monitor cytosolic protein folding, their respective contributions remain unclear. To bridge existing gaps, the pathways mediated by the San1 and Ubr1 E3 ligases were studied coordinately. We show that pathways share the same complement of chaperones needed for substrate trafficking, ubiquitination, and degradation. The significance became clear when Ubr1, like San1, was localized primarily to the nucleus. Appending nuclear localization signals to cytosolic substrates revealed that Ydj1 and Sse1 are needed for substrate nuclear import, whereas Ssa1/Ssa2 is needed both outside and inside the nucleus. Sis1 is required to process all substrates inside the nucleus, but its role in trafficking is substrate specific. Together, these data show that using chaperones to traffic misfolded cytosolic proteins into the nucleus extends the nuclear protein QC pathway to include cytosolic clients.


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