The Tubulin Superfamily

Abstract

In addition to the well-known α- and β-tubulin, which constitute the tubulin dimer, there are other related forms of tubulin, including γ, σ, ε, η and others. γ-Tubulin plays a key role in the nucleation of microtubule assembly at the centrosome. The roles of the other members of the tubulin superfamily are still being explored. It is interesting that all of them are found either in the centrosome or the very similar basal body; there is evidence that some of these play significant roles in the assembly of these organelles. The proteins of the tubulin superfamily are also related to the prokaryotic protein FtsZ, which plays a key role in cell division. Comparison of the sequences of all of these proteins allows for speculation about their evolution. These proteins and their evolution will be discussed in this chapter.