Ubiquitin receptors and protein quality control

Wang, Xuejun; Terpstra, Erin J

doi:10.1016/j.yjmcc.2012.09.012

Cited by 62 publications

(73 citation statements)

References 157 publications

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“…Previous studies have confirmed that protein ubiquitination serves multiple roles in different biological processes. It is known that ubiquitination is crucial for protein degradation (31). The E2 ubiquitin-conjugating enzyme RAD6 catalyzes target proteins through ubiquitination (22).…”

Section: Discussionmentioning

confidence: 99%

High expression of ubiquitin-conjugating enzyme E2A predicts poor prognosis in hepatocellular carcinoma

Shen

et al. 2018

Oncol Lett

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Abstract. The present study aimed to illustrate the association of the expression of ubiquitin-conjugating enzyme E2A (UBE2A) with the clinicopathological parameters and prognosis in hepatocellular carcinoma (HCC). The expression levels of UBE2A mRNA and protein in a total of 276 HCC tissues and six liver cell lines was detected by fluorescent quantitative polymerase chain reaction, western blotting and immunohistochemistry. Statistical analysis was also performed to assess the association of the expression of UBE2A with the clinicopathological parameters and prognosis by the GraphPad Prism and SPSS version 21.0 software. UBE2A mRNA and protein were highly expressed in HCC tissues compared with those in the adjacent normal tissue. Immunohistochemical analysis revealed that UBE2A protein was more strongly stained in the 276 paraffin-embedded HCC tissues as compared with the 63 adjacent normal tissue. Statistical analysis also demonstrated that UBE2A expression was significantly associated with histological differentiation, TNM stage and vascular invasion of HCC (P<0.05). Notably, HCC patients with a high expression of UBE2A had a shorter survival time as compared with those with a low expression of UBE2A. There results suggested that UBE2A may be involved in the pathogenesis of HCC and may serve as an important prognostic marker.Further exploration of the involvement of UBE2A in HCC development may provide novel therapeutic targets. IntroductionHepatocellular carcinoma (HCC) is the third leading cause of cancer-associated mortality worldwide and the fifth most common cancer type (1). HCC is a global health burden and its prevalence varies worldwide (2). The incidence rate is reported to be higher in Asia (>20 cases/100,000 individuals) in comparison with that in North America and Europe (<5 cases/100,000 individuals) (3). The prognosis of HCC is poor, as evident by the fact that the number of annual mortality cases (~600,000) is almost equal to the number of new cases diagnosed annually (4). The median rate for 1-year survival is 80% (range, 63-97%), for 3-year survival is 70% (range, 34-78%) and for 5-year survival is 50% (range, 17-69%) (5). Surgery remains the most important treatment strategy for patients with HCC. The 5-year survival rate of patients with early HCC subsequent to resection treatment reaches 50%, although these patients exhibit a high recurrence rate (6,7). Despite advances in the diagnosis (8) and treatment (9) of HCC, the prognosis of this disease remains poor (10). Therefore, further clarification of the mechanisms underlying its development is important (11,12).At present, the prognosis of HCC is predicted based on imaging findings and biomarkers. Various biomarkers, including α-fetoprotein (AFP) (13), des-γ-ca rboxy prothrombin (14) and α-l-fucosidase (15), have been identified over the past three decades. However, accurate indicators for the prognosis of HCC are limited. Consequently, there is an urgency to develop a novel biomarker for the prognosis of HCC.The ubiquitin system serves a ...

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Section: Discussionmentioning

confidence: 99%

High expression of ubiquitin-conjugating enzyme E2A predicts poor prognosis in hepatocellular carcinoma

Shen

et al. 2018

Oncol Lett

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“…If the proteins cannot be maintained in a soluble state and handled by the first lines of chaper one and UPS defence, selective macroautophagy can occur 8,45 . In macroautophagy, a portion of the cytoplasm containing damaged organelles and aberrant proteins are engulfed in a membrane bound compartment for degradation by lysosomes, after which the amino acids and fatty acids are recycled into ATP 46 .…”

Section: The Proteostasis Network Componentsmentioning

confidence: 99%

Proteostasis in cardiac health and disease

Henning

Brundel²

2017

Nat Rev Cardiol

141

126

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The worldwide increase in life expectancy gives rise to an increasing prevalence of cardiac diseases, which remain the leading cause of disability and death in the developed world [1][2][3] . Currently, the mechanisms under lying how ageing contributes to the initiation or acceler ation of cardiac diseases are essentially unresolved. Prevailing theories of ageing centre on gradual derail ment of cellular protein homeostasis -proteostasis -either by design (genetically) or by 'wear and tear' (environmentally) 3 . Central to the role of proteostasis derailment as a major factor in ageing is the observation that protein function declines over time.Proteins are the most versatile and complex macro molecules and are involved in the proper functioning of every biological process 4 . After synthesis as a poly peptide chain from the genetic code, proper function of a protein relies heavily on its correct folding into a 3D native state and on various post translational modifi cations, mostly involving the addition of chem ical groups (including phosphate, acetate, and carbo hydrate). Protein maturation, transport, and ultimately breakdown is monitored and supported by various classes of proteins, collectively called 'protein quality control' (PQC) [3][4][5] . Balanced proteostasis, therefore, depends on proper PQC and is crucial for cellular and organismal health 6 . The intricate network making up the PQC involves numerous proteins, of which the main players are the chaperones and their regula tors 4,7-9 (assisting in folding and refolding of proteins) and the pathways that clear irreversibly misfolded and aggregation prone proteins (the ubiquitin-proteasome system [UPS] and autophagy systems) 9-11 . With ageing, the gradual accumulation of misfolded or damaged pro teins, together with concomitant failure of PQC, results in proteotoxic stress and compromised defence against reactive oxygen species (ROS) 10 , a process that is likely to be accelerated in various age related diseases includ ing neurodegenerative diseases 12,13 , type 2 diabetes mel litus 14 , cancer 15 , and cardiac diseases [16][17][18][19][20] . In addition to the accumulation of misfolded proteins, ageing is accompanied by an imbalance in the proteome, as indi cated by lowered expression of chaperone, proteaso mal, ribosomal, and mitochondrial proteins, whereas proteins related to oxidative stress are upregulated 21,22 . Although mild impairment of proteostasis extends lifespan in Caenorhabditis elegans, referred to as hormesis, sustained impairment is accompanied by loss of PQC to neutralize this effect 3,5 . Importantly, evidence indicates that the amount of soluble, aggregate prone protein oligomers, rather than the abundance of pro tein aggregates, correlates with disease severity 23,24 . Therefore, protein aggregates, which contain both misfolded proteins and elevated levels of chaper ones, constitute an adequate PQC response, aimed at sequestering potentially harmful protein oligomers, rather than embodying the ultimate cellular threat 25 . This ...

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“…The immunoproteasome in non-immune cells can be induced by viral infection and γ-interferon and is presumably more suitable for generation of peptide fragments for antigen presentation [21]. In UPS-mediated protein degradation, ubiquitination and proteasomal degradation of a substrate is coupled via intra- and extra- proteasomal Ub receptors (Figure 2) [22]. …”

Section: Ups Dysfunction In Cardiac Proteotoxicitymentioning

confidence: 99%

The interplay between autophagy and the ubiquitin–proteasome system in cardiac proteotoxicity

Wang

2015

Biochimica et Biophysica Acta (BBA) - Molecular Basis of Diseas

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Proteotoxicity refers to the detrimental effects of damaged/misfolded proteins on the cell. Cardiac muscle is particularly susceptible to proteotoxicity because sustained and severe proteotoxic stress leads to cell death and cardiac muscle has very limited self-renewal capacity. The ubiquitin-proteasome system (UPS) and the autophagic-lysosomal pathway (ALP) are two major pathways responsible for degradation of most cellular proteins. Alterations of UPS and ALP functions are associated with the accumulation of proteotoxic species in the heart, a key pathological feature of common forms of heart disease including idiopathic, ischemic, and pressure-overloaded cardiomyopathies and a large subset of congestive heart failure. Emerging evidence suggests proteasome inhibition or impairment activates autophagy and conversely, acute ALP inhibition may sometimes increase intrinsic proteasome peptidase activities but chronic ALP inhibition hinders UPS performance in ubiquitinated protein degradation. The exact molecular basis on which the two degradative pathways interact remains largely undefined. Here we review current understanding of the roles of the UPS and autophagy in the control of cardiac proteotoxicity, with a specific focus on the crosstalk between the two pathways.

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Ubiquitin receptors and protein quality control

Cited by 62 publications

References 157 publications

High expression of ubiquitin-conjugating enzyme E2A predicts poor prognosis in hepatocellular carcinoma

High expression of ubiquitin-conjugating enzyme E2A predicts poor prognosis in hepatocellular carcinoma

Proteostasis in cardiac health and disease

The interplay between autophagy and the ubiquitin–proteasome system in cardiac proteotoxicity

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