Stathmin

Stathmin, also known as metablastin and oncoprotein 18, is a protein that in humans is encoded by the STMN1 gene. Stathmin is a highly conserved 17 kDa protein that is crucial for the regulation of the cell cytoskeleton. Changes in the cytoskeleton are important because the cytoskeleton is a scaffold required for many cellular processes, such as cytoplasmic organization, cell division and cell motility. More specifically, stathmin is crucial in regulating the cell cycle. It is found solely in eukaryotes. Its function as an important regulatory protein of microtubule dynamics has been well-characterized. Eukaryotic microtubules are one of three major components of the cell's cytoskeleton. They are highly dynamic structures that continuously alternate between assembly and disassembly. Stathmin performs an important function in regulating rapid microtubule remodeling of the cytoskeleton in response to the cell's needs. Microtubules are cylindrical polymers of α,β-tubulin. Their assembly is in part determined by the concentration of free tubulin in the cytoplasm. At low concentrations of free tubulin, the growth rate at the microtubule ends is slowed and results in an increased rate of depolymerization (disassembly).