Intermediate filament proteins in nonfilamentous structures: Transient disintegration and inclusion of subunit proteins in granular aggregates |
| |
Authors: | Werner W Franke Erika Schmid Christine Grund Benjamin Geiger |
| |
Institution: | 1. Division of Membrane Biology and Biochemistry Institute of Cell and Tumor Biology German Cancer Research Center Heidelberg D-6900, Federal Republic of Germany;2. Department of Chemical Immunology The Weizmann Institute of Science Rehovot 76100, Israel |
| |
Abstract: | The intermediate filament cytoskeleton of cultured bovine kidney epithelial cells and human HeLa cells changes dramatically during mitosis. The bundles of cytokeratin and vimentin filaments progressively unravel into protofilament-like threads of 2–4 nm diameter, and intermediate filament protein is included in numerous, variously sized (2–15 μm) spheroidal aggregates containing densely stained granular particles of 5–16 nm diameter. We describe these mitotic bodies in intact cells and in isolated cytoskeletons. In metaphase to anaphase of normal mitosis and after colcemid arrest of mitotic stages, many cells contain all their detectable cytokeratin and vimentin material in the form of such spheroidal aggregate bodies, whereas in other mitotic cells such bodies occur simultaneously with bundles of residual intermediate filaments. In telophase, the extended normal arrays of intermediate filament bundles are gradually reestablished. We find that vimentin and cytokeratins can be organized in structures other than intermediate filaments. Thus, at least during mitosis of some cell types, factors occur that promote unraveling of intermediate filaments into protofilament-like threads and organization of intermediate filament proteins into distinct granules that form large aggregate bodies. Some cells, at least certain epithelial and carcinoma cells, may contain factors effective in structural modulation and reorganization of intermediate filaments. |
| |
Keywords: | |
本文献已被 ScienceDirect 等数据库收录! |
|