Linkage-specific ubiquitylation patterns as highly sensitive markers for neurodegenerative disease - Linkage-specific ubiquitylation patterns as highly sensitive markers for neurodegenerative
disease
Abstract:
Despite an intensive effort by the government, pharmaceutical companies and academic
groups, the diagnosis and treatment of Alzheimer's disease remains elusive. The incidence of
Alzheimer's disease is predicted to increase, reaching more than 10 million cases in USA by
2025. Thus, the development of quantitative, simple and reproducible diagnostic markers is
extremely important. Current methods for diagnosis of Alzheimer's disease are dependent on
clinical and neuropsychological assessment, cerebrospinal fluid (CSF) analysis, and brain-
imaging procedures, all of which have significant cost- and access-to-care barriers. Thus the
need for simple blood-based biomarkers has never been greater. We hypothesize that
dysfunction in the ubiquitin proteasome pathway occurs decades before the clinical
manifestation of Alzheimer's disease symptoms. Neurons generally do not divide, and their
survival depends heavily on the removal of misfolded proteins. The first step in
neurodegenerative disease begins with a diminished response to unfolded protein removal, and
proteasomal dysfunction. Therefore, neuronal diseases are marked by the appearance or
change in pattern of ubiquitylated proteins -- the main hypothesis of this proposal, which
describes a unique combination of affinity purification of ubiquitylated proteins and mass
spectroscopy approaches to detect ubiquitylated proteins and also determine the nature of the
poly-ubiquitin chain linkage. Although the roles of the ubiquitin pathway in cell physiology and
pathology have been recognized for the last three decades, surprisingly there are no reliable
and sensitive methods available to monitor patterns of ubiquitylation. The development of this
technology will enable clinicians to make early diagnoses of Alzheimer's disease, facilitate the
discovery of disease modifying drugs, and open doors for cell biologists to rapidly identify
patterns of poly-ubiquitylated proteins in tissues, cells or body fluids.