TUBULIN POSTTRANSLATIONAL MODIFICATIONS IN THE PRIMITIVE PROTIST TRICHOMONAS-VAGINALIS

Using several specific monoclonal antibodies, we investigated the occu rrence and distribution of different post-translationally modified tub ulin during interphase and division of the primitive flagellated proti st Trichomonas vaginalis. Immuno-blotting and immunofluorescence exper iments revealed that interphasic microtubular structures of T. vaginal is contained acetylated and glutamylated but non-tyrosinated and non-g lycylated [Brugerolle and Adoutte, 1988: Bio Systems 21: 255-268] tubu lin. Immunofluorescence studies performed on dividing cells showed tha t the extranuclear mitotic spindle (or paradesmosis) was acetylated an d glutamylated, which contrast with the ephemeral nature of this struc ture. Newly formed short axostyles also contained acetylated and gluta mylated tubulin suggesting that both post-translational modifications might take place very early after assembly of microtubular structures. Our results indicate that acetylation and glutamylation of tubulin ap peared early in the history of eukaryotes and could reflect the occurr ence of post-translational modifications of tubulin in the primitive e ukaryotic cells. These cells probably had a highly ordered cross-linke d microtubular cytoskeleton in which microtubules showed a low level o f subunit exchange dynamics. (C) 1996 Wiley-Liss, Inc.