Эукариоттардағы Статмин ақуызы және цитоскелеттің реттелуі

Protein in Eukaryotes
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. 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).

Stathmin, and the related proteins SCG10 and XB3, contain a N terminal domain (XB3 contains an additional N terminal hydrophobic region), a 78 amino acid coiled coil region, and a short C terminal domain.

The function of Stathmin is to regulate the cytoskeleton of the cell. The cytoskeleton is made up of long hollow cylinders named microtubules. These microtubules are made up of alpha and beta tubulin heterodimers. The changes in cytoskeleton are known as microtubule dynamics; the addition of the tubulin subunits lead to polymerisation and their loss, depolymerisation. Additionally, Stathmin is thought to have a role in cell signaling pathway. Stathmin is a ubiquitous phosphorylated protein which makes it act as an intracellular relay for diverse regulatory pathways, functioning through a variety of second messengers. Its phosphorylation and gene expression are regulated throughout development and in response to extracellular signals regulating cell proliferation, differentiation and function.

Stathmin interacts with two molecules of dimeric α,β tubulin to form a tight ternary complex called the T2S complex.