The C Terminus of Tubulin, a Versatile Partner for Cationic Molecules

• DOI: 10.1074/jbc.m110.144089
• Publication Date: 2010-11-10T01:13:26Z
• Authors: Julien Lefèvre; Konstantin G. Che...; Vandana Joshi; Stéphanie Delga; Flavio Toma; David Pastré; Patrick A. Curmi; Philippe Savarin
• Keywords: Isothermal Titration Calorimetry

The C-terminal region of tubulin is involved in multiple aspects the regulation microtubule assembly. To elucidate molecular mechanisms this regulation, we study here, using different approaches, interaction Tau, spermine, and calcium, three representative partners region, with a peptide composed last 42 residues α1a-tubulin. results show that their binding involves overlapping amino acid stretches region: 421-441 for 430-432 444-451 421-443 calcium. Isothermal titration calorimetry, NMR, cosedimentation experiments Tau spermine have similar micromolar affinities, whereas stoichiometry differs (C-terminal peptide/spermine 1:2, peptide/Tau 8:1). Interestingly, known as negative regulator assembly, can compete domain positive effect these two on assembly vitro. This observation opens up possibility calcium may participate vivo through direct (still unknown) or indirect mechanism (displacement partners). functional importance part was also underlined by an α-tubulin mutant deleted from 23 does not incorporate properly into network HeLa cells. Together, provide structural basis better understanding complex interactions putative competition cationic tubulin.