Microtubule-associated protein tau is predominantly expressed in neurons in the form of multiple isoforms generated by alternative splicing. These isoforms differ in the presence of either three or four microtubule-binding repeats. These binding regions not only regulate tau's interaction with microtubules but are also critically involved in its pathological self-aggregation. Such aggregates are a defining feature of a group of neurodegenerative disorders collectively referred to as tauopathies. In this work, we examine the mechanisms underlying tau self-aggregation, the molecular and cellular factors that drive this process, and the structural features of tau aggregates. Aggregates composed of isoforms with three versus four microtubule-binding repeats display distinct morphologies, which serve as pathological hallmarks for different tauopathies. Finally, we discuss potential therapeutic strategies aimed at preventing or promoting the clearance of tau aggregates.
©The Author(s) 2025. Open Access. This article is licensed under a Creative Commons CC-BY International License.