PLANT TUBULIN PHOSPHORYLATION AND ITS ROLE IN CELL CYCLE PROGRESSION

Review of the literature reveals that plant tubulins call undergo extensive phosphorylation by different types of protein kinases, and that phosphorylation on serine/threonine residues as well as at tyrosine residues call result in the generation of a high level of polymorphism of plant tubulin . Biochemical evidence is presented to demonstrate that phosphorylation of plant tubulin is controlled by different types of protein kinases. Because the phosphorylation sites call be located along the whole length of both the alpha and beta tubulins, it is possible that this type of post-translational modification in plants call participate in modulating the tubulin-tubulin interaction, interactions of tubulins With other proteins (including MAPs and proteins of other cytoskeletal structures), with thee plasma membrane and in regulating the functional stability/instability of microtubular arrays. The possible effects of different types of tubulin phosphorylation on cell cycle progression in higher plants are discussed.