Identification of two new members of the tubulin family.
Analysis of the delta- and epsilon-tubulin sequences indicates that they both consist of two structural domains of which the N-terminal domain can bind to alpha/beta heterodimers while the C-terminal domain probably binds to a non-tubulin protein. Both additional tubulins probably bind GTP but lack GTPase activity, while their synthesis requires the TCP1 chaperonine but is not autoregulated. Although these properties resemble those of gamma-tubulin, the low sequence identity (Table I) demonstrates that the gamma-, delta-, and epsilon-proteins should be classed as different members of the tubulin family. The identification of these additional members is unexpected. Examination of the cellular expression and distribution of the delta- and epsilon-tubulins, and whether other organisms contain homologous genes, may reveal further features of the eukaryotic cytoskeleton.
Burns
R G
RG
Biophysics Section, Blackett Laboratory, Imperial College of Science, Technology and Medicine, London, United Kingdom.
D000595:Amino Acid Sequence; D000818:Animals; D002107:Caenorhabditis; D006160:Guanosine Triphosphate / Q000378:metabolism; D006801:Humans; D008969:Molecular Sequence Data; D012441:Saccharomyces cerevisiae; D014404:Tubulin / Q000737:chemistry* / Q000378:metabolism
D014404:Tubulin; D006160:Guanosine Triphosphate