P150Glued Regulates Microtubule Dynamics in Neurons through Tandem Tubulin-Binding Domains

Abstract

Regulation of microtubule dynamics is critical, particularly in neurons, where defects may contribute to neurodegeneration. Here, we demonstrate in vitro using TIRF microscopy and in primary neurons using live-cell imaging that the p150Glued subunit of dynactin regulates microtubule dynamics. To modify dynamics, p150Glued must be dimerized, and it must bind soluble tubulin, an interaction that we find requires tandem CAP-Gly and basic domains. p150Glued is alternatively spliced in vivo, with the full length isoform including both these domains expressed primarily in neurons. Accordingly, depletion of p150Glued in a non-polarized cell line does not alter microtubule dynamics, while p150Glued RNAi in neurons leads to a dramatic increase in microtubule catastrophe. Strikingly, a Parkinson syndrome-associated mutation blocks this microtubule-stabilizing activity both in vitro and in neurons. Together, our data reveal that p150Glued plays a crucial role in promoting microtubule stability in neurons, and that defects in this function may lead to neurodegeneration.