[The comparative structural-functional characteristics of the cytoskeleton of animals and higher plants]

The peculiarities of structure, location and dynamics of microtubules (Mts) and microfilaments (Mfs) in cells of animals and of higher plants (growing by elongation and apical growth) are discussed. It is shown that in animal cells Mt-skeleton located mainly in the depths of the cytoplasm is responsible for directed intracellular movement and characteristic position of cell components. Animal Mf-skeleton forming a dense network is most often aggregated at the cell periphery. Its primary function is the shaping and locomotion of the cell. In contrast, one of the most characteristic features of the cytoskeleton in the elongating plant cells is the presence of only cortical Mts closely linked to the plasmalemma. Higher plant Mt-skeleton is involved primarily in the orientation of newly depositing cellulosic cell wall microfibrils and thus it controls the direction of cell growth which determines the cell shape. It also mediates (by means of preprophase Mt-band) the orientation of cytokinesis. Thus in plants the principal role of the Mt-skeleton is the control of morphogenesis. Far less important is supporting function of plant Mts. The nuclear envelope is main Mt organizing center in plant cells. Unlike Mts, plant Mf-skeleton is concentrated in the cell depths and is the involved in the intracellular transport and characteristic positioning of the cell components. Apically growing cells such as root hairs typically contain deeply distributed Mts in addition to cortical ones. The former may participate in the transfer of nucleus and/or plastids.