Overview:

Stathmin is a ubiquitous, highly conserved protein present in the cytoplasm in a variety of unphosphorylated and phosphorylated forms. Stathmin functions as an intracellular relay integrating regulatory signals of the cellular environment (1). Stathmin is involved in the regulation of the microtubule filament system. Stathmin binds tubulin in a ternary complex, with 2 tubulins for every stathmin and this complex interferes with microtubule dynamics in vitro and in vivo. Overexpression of several stathmin mutants suggest that stathmin induces depolymerization of interphase and mitotic microtubules in its unphosphorylated state, but is inactivated by phosphorylation in mitosis (2).

References:

1. Sobel, A. Stathmin: a relay phosphoprotein for multiple signal transduction? Trends Biochem. Sci. 16: 301-305, 1991.2. Gavet, O. et al: The stathmin phosphoprotein family: intracellular localization and effects on the microtubule network. J. Cell Sci. 111: 3333-3346, 199.