Tubulin, C-terminal
IPR023123
Definition
Microtubules are polymers of tubulin, a dimer of two 55kDa subunits, designated alpha and beta [[cite:PMID:3896122], [cite:PMID:2194680]]. Within the microtubule lattice, α-β heterodimers associate in a head-to-tail fashion, giving rise to microtubule polarity. Fluorescent labelling studies have suggested that tubulin is oriented in microtubules with beta-tubulin toward the plus end PMID:8102497. For maximal rate and extent of polymerisation into microtubules, tubulin requires GTP. Two molecules of GTP are bound at different sites, termed N and E. At the E (Exchangeable) site, GTP is hydrolysed during incorporation into the microtubule. Close to the E site is an invariant region rich in glycine residues, which is found in both chains and is thought to control access of the nucleotide to its binding site PMID:3680207. Most species, excepting simple eukaryotes, express a variety of closely-related alpha- and beta-isotypes. A third family member, gamma tubulin, has also been identified in a number of species. Gamma tubulin is found at microtubule-organising centres, such as the spindle poles or the centrosome, suggesting that it is involved in minus-end nucleation of microtubule assembly PMID:8274140. Further eukaryotic tubulins (gamma, epsilon, zeta) that are restricted to certain lineages or species have been reported [[cite:PMID:25169981], [cite:PMID:26234217]]. Bacterial and archaeal homologues of tubulin have been discovered. BtubA and BtubB, two bacterial homologues in the genus Prosthecobacter, have probably been derived by horizontal gene transfer [[cite:PMID:12486237], [cite:PMID:15967998]]. This entry represents the extreme C-terminal structural domain of both alpha and beta tubulin. It forms a helix hairpin PMID:11030624.
23 human proteins with this domain
Each is a reviewed human protein in the Seroatlas serome and a potential autoantibody target; this domain groups them into one antibody-relevant category. Every entry links to its own record.
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