XVI International Botanical Congess

Although multiple tubulin (Tub) genes have been described in higher plants, our knowledge about post-translational modifications of plant Tub remains limited. This has prompted us to investigate further the mechanisms and functional role of such modifications of plant Tub. It was shown that both a- and ß-Tub were intensively phosphorylated during activation of cAMP-, Ca2+-, Ca2+-calmodulin-dependent PKs and PK C. Polyglutamylated, tyrosinated, nontyrosinated, acetylated and ?2-Tub variants were detected on a-Tub, polyglutamylation was also found on ß-Tub. Additionally, the possibility of phosphorylation on tyrosine residues of a- and ß-Tub was established. The distribution of modified Tub in MT arrays throughout the mitotic cycle implied that each of the established modifications (phosphorylation not studied) participated in the formation of all MT figures, but sometime in specific manner. The differences were observed in the staining of interphase and mitotic MTs, too. These modifications can participate in the generation of high polymorphism of Tub.