SUMOylation of α-tubulin is a novel modification regulating microtubule dynamics. (4th January 2021) - Feng, Wenfeng
Abstract: Microtubules (MTs) are regulated by a number of known posttranslational modifications (PTMs) on α/β -tubulin to fulfill diverse cellular functions. Here, we showed that SUMOylation is a novel PTM on α -tubulin in vivo and in vitro . The SUMOylation on α -tubulin mainly occurred at Lys 96 (K96), K166, and K304 of soluble α -tubulin and could be removed by small ubiquitin-related modifier (SUMO)-specific peptidase 1. In vitro experiments showed that tubulin SUMOylation could reduce interprotofilament interaction, promote MT catastrophe, and impede MT polymerization. In cells, mutation of the SUMOylation sites on α -tubulin reduced catastrophe frequency and increased the proportion of polymerized α -tubulin, while upregulation of SUMOylation with fusion of SUMO1 reduced α -tubulin assembly into MTs. Additionally, overexpression of SUMOylation-deficient α -tubulin attenuated the neurite extension in Neuro-2a cells. Thus, SUMOylation on α -tubulin represents a new player in the regulation of MT properties.