Biopolymers and cell. 2008; 24 (6): 470 - 475

Subcellular localization of S6K1 and S6K2 forms of ribosomal protein S6 kinase in rat thyrocytes under conditions of two- and three-dimensional culture

A. I. Khoruzhenko, O. V. Cherednyk, V. V. Filonenko

The aim of this work was to study the link between activation of processes of migration, proliferation, loss of thyrocyte follicle organization at different culture conditions and subcellular localization of S6K1/2. The subcellular redistribution of S6K1/2 takes place in the rat thyrocyte monolayer culture where S6K1/2 was detected not only in the cytoplasm but in the nuclei of cells as well|. In addition, the content of S6K1/2 in proliferating cells was increased. The subcellular| localization of S6K1/2 in thyrocytes cultivated as follicles was similar to that observed in normal thyroid tissue. Subcellular relocalization of S6K1/2 was detected only in certain cellular population, which for some reasons lost follicle organization and, consequently, functional activity. Thus, the changes in subcellular localization of S6K1/2 in cultivated thyrocytes are directly related to the level of differentiation, unlike proliferation and migration of these cells.

Keywords: ribosomal protein S6 kinase, thyrocytes, level of differentiation.