Tubb is a globular protein that pairs with alpha-tubulin to form a heterodimer. These heterodimers then polymerize to form the hollow, cylindrical microtubules. The structure of tubb includes a GTP-binding domain, which is crucial for its polymerization and stability. The dynamic instability of microtubules, characterized by phases of growth and shrinkage, is regulated by the hydrolysis of GTP bound to tubb.
