Summary
Tubulin in molecular biology can refer either to the tubulin protein superfamily of globular proteins, or one of the member proteins of that superfamily. α- and β-tubulins polymerize into microtubules, a major component of the eukaryotic cytoskeleton. Microtubules function in many essential cellular processes, including mitosis. Tubulin-binding drugs kill cancerous cells by inhibiting microtubule dynamics, which are required for DNA segregation and therefore cell division. In eukaryotes, there are six members of the tubulin superfamily, although not all are present in all species. Both α and β tubulins have a mass of around 50 kDa and are thus in a similar range compared to actin (with a mass of ~42 kDa). In contrast, tubulin polymers (microtubules) tend to be much bigger than actin filaments due to their cylindrical nature. Tubulin was long thought to be specific to eukaryotes. More recently, however, several prokaryotic proteins have been shown to be related to tubulin. Tubulin is characterized by the evolutionarily conserved Tubulin/FtsZ family, GTPase protein domain. This GTPase protein domain is found in all eukaryotic tubulin chains, as well as the bacterial protein TubZ, the archaeal protein CetZ, and the FtsZ protein family widespread in bacteria and archaea. Microtubule α- and β-tubulin polymerize into dynamic microtubules. In eukaryotes, microtubules are one of the major components of the cytoskeleton, and function in many processes, including structural support, intracellular transport, and DNA segregation. Microtubules are assembled from dimers of α- and β-tubulin. These subunits are slightly acidic, with an isoelectric point between 5.2 and 5.8. Each has a molecular weight of approximately 50 kDa. To form microtubules, the dimers of α- and β-tubulin bind to GTP and assemble onto the (+) ends of microtubules while in the GTP-bound state. The β-tubulin subunit is exposed on the plus end of the microtubule, while the α-tubulin subunit is exposed on the minus end.
About this result
This page is automatically generated and may contain information that is not correct, complete, up-to-date, or relevant to your search query. The same applies to every other page on this website. Please make sure to verify the information with EPFL's official sources.