Stathmins

Stathmins are a family of phosphoproteins that play a crucial role in regulating microtubule dynamics within eukaryotic cells. These proteins are known for their ability to bind to tubulin dimers, the building blocks of microtubules, and prevent their polymerization. This inhibition leads to microtubule depolymerization, effectively shortening existing microtubules and reducing the overall number of microtubules in the cell. Stathmins are also referred to as Op18, a name derived from their discovery in mouse brain extracts.

The activity of stathmins is tightly controlled by post-translational modifications, particularly phosphorylation. Specific kinases, such as the Aurora kinases and the cell cycle-dependent kinase (CDK), can phosphorylate stathmins at various sites. Phosphorylation generally reduces stathmin's ability to bind tubulin, thereby promoting microtubule polymerization. This dynamic regulation allows cells to rapidly alter their microtubule network in response to various stimuli and during different cellular processes.

Stathmins are involved in a wide range of cellular functions. They are particularly important during cell division, where they contribute to the formation and dynamics of the mitotic spindle, a structure essential for chromosome segregation. Beyond mitosis, stathmins also influence cell migration, cell shape, and intracellular transport. Dysregulation of stathmin expression or activity has been implicated in various diseases, including cancer, where altered microtubule dynamics can promote tumor growth and metastasis. Consequently, stathmins are considered potential therapeutic targets for cancer treatment.