The Ubiquitin System in Alzheimer’s Disease

Lee D. Harris, Sarah Jasem, Julien D. F. Licchesi

Research output: Chapter or section in a book/report/conference proceedingChapter or section

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Alzheimer’s disease (AD) is the most common form of dementia, most prevalent in the elderly population and has a significant impact on individuals and their family as well as the health care system and the economy. While the number of patients affected by various forms of dementia including AD is on the increase, there is currently no cure. Although genome-wide association studies have identified genetic markers for familial AD, the molecular mechanisms underlying the initiation and development of both familial and sporadic AD remain poorly understood. Most neurodegenerative diseases and in particular those associated with dementia have been defined as proteinopathies due to the presence of intra- and/or extracellular protein aggregates in the brain of affected individuals. Although loss of proteostasis in AD has been known for decades, it is only in recent years that we have come to appreciate the role of ubiquitin-dependent mechanisms in brain homeostasis and in brain diseases. Ubiquitin is a highly versatile post-translational modification which regulates many aspects of protein fate and function, including protein degradation by the Ubiquitin–Proteasome System (UPS), autophagy-mediated removal of damaged organelles and proteins, lysosomal turnover of membrane proteins and of extracellular molecules brought inside the cell through endocytosis. Amyloid-β (Aβ) fragments as well as hyperphosphorylation of Tau are hallmarks of AD, and these are found in extracellular plaques and intracellular fibrils in the brain of individuals with AD, respectively. Yet, whether it is the oligomeric or the soluble species of Aβ and Tau that mediate toxicity is still unclear. These proteins impact on mitochondrial energy metabolism, inflammation, as well as a number of housekeeping processes including protein degradation through the UPS and autophagy. In this chapter, we will discuss the role of ubiquitin in neuronal homeostasis as well as in AD; summarise crosstalks between the enzymes that regulate protein ubiquitination and the toxic proteins Tau and Aβ; highlight emerging molecular mechanisms in AD as well as future strategies which aim to exploit the ubiquitin system as a source for next-generation therapeutics.

Original languageEnglish
Title of host publicationProteostasis and Disease
Subtitle of host publicationFrom Basic Mechanisms to Clinics
EditorsR. Barrio, J. D. Sutherland, M. S. Rodriguez
Place of PublicationSwitzerland
Number of pages27
Publication statusPublished - 2020

Publication series

NameAdvances in Experimental Medicine and Biology
ISSN (Print)0065-2598
ISSN (Electronic)2214-8019

Bibliographical note

Funding Information:
We thank Dr. Robert Williams for feedback on the chapter. The authors acknowledge funding from Alzheimer?s Research UK (pilot grant ARUK-PPG2015A-16) as well as Bath/Bristol ARUK network pilot grants. Lee Harris is funded by an ARUK PhD studentship (ARUK-PhD2017-28), Sarah Jasem was funded through a Kuwait Science PhD Scholarship. We also thank COST ACTION BM1307 ? COST Proteostasis ? as well as the Bath/Bristol ARUK Network for conference travel awards.


  • Alzheimer’s disease
  • Amyloid beta
  • Deubiquitinases
  • E3 ubiquitin ligases
  • Tau
  • Ubiquitin-proteasome system

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)


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