MAPT and neurodegenerative disease: Research on the structure and function of tau protein and the mechanism by which it aggregates abnormally is of great significance for the treatment of related diseases; therefore, this review focuses on the roles of tau protein in neurodegenerative diseases, the post-translational modification of tau protein, the factors affecting the aberrant phosphorylation of tau protein, and advances in the research and development of drugs that use tau protein as a target.