Tubulin Delta (TUBd)

The deduced 453-amino acid protein has a calculated molecular mass of 51 kD. TUBD1 contains the conserved GTP-binding domain shared with other tubulins, but it lacks the highly acidic C terminus characteristic of alpha-tubulin and beta-tubulin. Relative to other tubulins, TUBD1 also has a 5-amino acid insertion between helices 6 and 7 and a 21-residue insertion at the end of helix 9.

TUBD1 shares 40% amino acid identity with Chlamydomonas delta-tubulin and 85% identity with mouse delta-tubulin. Within dividing osteogenic sarcoma cells, TUBD1 partially colocalized with both centrin and gamma-tubulin, but it was most prominent between the centrioles within a centrosome. Its localization was independent of microtubules.