Phase separation of +TIP-networks regulates microtubule dynamics and Tubulin engineering allows for precise post-translation modifications

titlePhase separation of +TIP-networks regulates microtubule dynamics and Tubulin engineering allows for precise post-translation modifications
start_date2023/12/07
schedule11h30
onlineno
location_infoAmphithéâtre Serge Kampf
summaryRegulation of microtubule dynamics is essential for diverse cellular functions, and proteins that bind to dynamic microtubule ends can regulate network dynamics. Here we show that two conserved microtubule end-binding proteins, CLIP-170 and EB3, undergo phase separation and form dense liquid-networks. When CLIP-170 and EB3 act together the multivalency of the network increases, which synergistically increases the amount of protein in the dense phase. In vitro and in cells these liquid networks can condense tubulin. In vitro in the presence of microtubules, EB3/CLIP-170 phase separation can co-condense tubulin all along the microtubule. At this condition microtubule growth speed increases up to two-fold and depolymerization events are strongly reduced, compared to conditions with phase separation deficient networks. Our data show that phase separated EB3/CLIP-170 networks impact microtubule growth dynamics beyond direct protein-microtubule interactions. A further mechanism to regulate microtubule dynamics it through of post-translational modifications (PTMs). Microtubules carry patterns of PTMs which are important for the regulation of key cellular processes. We developed a semisynthetic method to produce tubulin carrying defined PTMs. Using these designer tubulins, we find that α-tubulin polyglutamylation promotes its detyrosination by enhancing the activity of the carboxypeptidase vasohibin/SVBP.
responsiblesSadoul