This family includes tubulin alpha-, beta-, gamma-, delta-, epsilon, and zeta-tubulins as well as FtsZ and CetZ, all of which are involved in polymer formation. Tubulin is the major component of microtubules, but also exists as a heterodimer and as a curved oligomer. Microtubules exist in all eukaryotic cells and are responsible for many functions, including cellular transport, cell motility, and mitosis. FtsZ forms a ring-shaped septum at the site of bacterial cell division, which is required for constriction of cell membrane and cell envelope to yield two daughter cells. FtsZ can polymerize into tubes, sheets, and rings in vitro and is ubiquitous in eubacteria, archaea, and chloroplasts. A recent study found that CetZ proteins, formerly annotated FtsZ type 2, are not required for cell division, whereas FtsZ proteins play an important role. Instead, CetZ proteins are shown to be involved in controlling archaeal cell shape dynamics. The results from inactivation studies of CetZ proteins in Haloferax volcanii suggest that CetZ1 is essential for normal swimming motility and rod-cell development.
Jiyao W et al.(2023). "The conserved domain database in 2023.",