Control of intermediate filament protein synthesis by cell-cell interaction and cell configuration.

The expression of cytokeratins and vimentin was investigated in epithelial cells under conditions of varied cell spreading and cell-cell contact. When extensive cell-cell contact was achieved in dense monolayer cultures, or in suspension in multicellular aggregates, the cells synthesized high levels of cytokeratins and low levels of vimentin. In contrast, sparse monolayer and suspension cultures, with minimal cell-cell contact, synthesized low levels of cytokeratins and high levels of vimentin. The ratio of cytokeratin to vimentin synthesis was independent of the cell cycle and was also reflected at the level of mRNA translational activity in vitro. Thus control of cytokeratin synthesis involves cell-cell contact, while vimentin synthesis responds to cell shape changes.