Pathology of different tau protein species in neurodegenerative diseases: Alzheimer’s disease, corticobasal degeneration, and progressive supranuclear palsy

Abstract

Background and Aim: Tau protein is a microtubule-associated protein that plays a critical role in microtubule dynamics and maintaining the structure of neurons. Tau isoforms with three or four repeated domains at the c-terminal are known as 3R or 4R isoforms, respectively. Hyperphosphorylation of tau impairs its original structure and function and causes accumulation of tau as tangled filaments known as neurofibrillary tangles. The aim of this study was to review the structure and physiological function of tau and also the role of accumulation and deposition of tau in induction of neurodegenerative diseases. Materials and Methods: Relevant reports about the deposition of tau protein in neurodegenerative diseases were summarized from scientific articles. Results: Deposition of the filamentous tau in neurons and glial cells causes cell damage and induces neurodegenerative diseases such as Alzheimer’s disease (AD), cortico-basal degeneration (CBD), and progressive supranuclear palsy (PSP). The type of tau isoform and its site of deposition in neurons, astrocytes, and oligodendrocytes are different in these diseases, which can be a useful clue for precise diagnosis of the above mentioned diseases. In AD both 3R and 4R isoforms are deposited only in neurons, but in PSP and CBD only 4R isoform is deposited in neurons and glial cells. Conclusion: Knowledge of the physiological functions and pathogenesis of tau and decreasing the hyperphosphorylated form of tau by inhibition of protein kinases, can lead to development of a diagnostic and therapeutic strategy for neurodegenerative diseases induced by tau protein. Tau protein, Protein kinases, Neurofibrillary tangles, Tauopathies

Keywords

• tau protein
• protein kinases
• neurofibrillary tangles
• tauopathies