Microtubule dynamics is modulated by many cellular factors including stathmin family proteins. Vertebrate stathmins sequester two ab-tubulin heterodimers into a tight complex that cannot be incorporated in microtubules. Stathmins are regulated at the expression level during development and among tissues; they are also regulated by phosphorylation. Here, we study the dissociation kinetics of tubulin:stathmin assemblies in presence of different tubulin-binding proteins and identify a critical role of the Cterminus of the stathmin partner. Destabilizing this C-terminal region may represent an additional regulatory mechanism of the interaction with tubulin of stathmin proteins.