Beta-tubulin (β-tubulin)

Beta-tubulin is one of the two major subunits (alongside alpha-tubulin) forming the heterodimeric building blocks of microtubules, essential cytoskeletal filaments in all eukaryotic cells. Each tubulin monomer (~50 kDa) binds a guanine nucleotide—GTP in β-tubulin is hydrolyzable and crucial for microtubule dynamics. Microtubules assemble from linear protofilaments of α/β-tubulin dimers and play key roles in maintaining cell shape, chromosome segregation during mitosis and meiosis, intracellular transport, and motility of cilia and flagella[1][5][6][8][9]. Several β-tubulin isotypes exist, encoded by different genes (e.g., β1, β2, β3, β4a, β4b, β5, β6), with some tissues expressing specific isotypes (e.g., β3 in neurons)[2][10]. Post-translational modifications and isotype switching can influence microtubule function and confer resistance to anti-microtubule cancer drugs[5][7][10]. β-tubulin is the molecular target for a variety of anticancer drugs, many of which are essential in modern chemotherapy regimens. Drug-induced interference with microtubule dynamics can lead to cell cycle arrest and apoptosis in rapidly dividing cells, but also poses risks for toxicity in non-cancer tissues, especially nerves and bone marrow[5][7]. β-tubulin is overexpressed or mutated in several cancers and is considered a central player in the development of resistance to microtubule-targeting agents[5][7][10].

Other names

Beta tubulinTUBB (gene symbol)Microtubule beta chainTUBB1, TUBB2A, TUBB3, etc. (for specific isotypes)

Stabilization of microtubules (e.g., by paclitaxel); Destabilization/depolymerization of microtubules (e.g., by vincristine, colchicine); Inhibition of microtubule dynamics leading to mitotic arrest and apoptosis