Alpha-tubulin ubiquitous (tubulin-alpha) is the major constituent of microtubules. Tubulin-alpha binds two moles of GTP, one at an e, Xenopus/Amphibian,changeable site on the beta chain and one at a non-e, Xenopus/Amphibian,changeable site on the alpha-chain. Acetylation of tubulin-alpha at Lys-40 stabilizes microtubules and affects affinity and processivity of microtubule motors. This modification has a role in multiple cellular functions, ranging from cell motility, cell cycle progression or cell differentiation to intracellular trafficking and signaling.