Regulation of neuronal microtubule dynamics by tau: Implications for tauopathies

In specialized cell types such as neurons, microtubules maintain the integrity of axons by forming stable bundles and facilitate the transport of synaptic vesicles. The cells regulate the stability and dynamics of microtubules using a diverse array of mechanisms. One of the mechanisms involves the interaction of microtubules with its associated proteins. Microtubule-associated proteins (MAPs) may have either stabilizing or destabilizing effects on the microtubules. Tau, a neuronal MAP, promotes the assembly and bundling of microtubules and suppresses microtubule dynamics. Abnormal functioning of tau is implicated in several neuronal disorders such as Alzheimer's disease (AD) and Parkinson's disease (PD), wherein tau forms insoluble aggregates and causes neurotoxicity. In this review, we focus on the effects of tau on neuronal microtubule stability and dynamics. We also discuss the factors that lead to tau aggregation and the resulting destabilization of microtubules and the implications of this phenomenon in the AD and other tauopathies.