The organization of cytokeratin filaments in the intestinal epithelium
Franke, W.W.; Appelhans, B.; Schmid, E.; Freudenstein, C.; Osborn, M.; Weber, K.
European Journal of Cell Biology 19(3): 255-268
1979
ISSN/ISBN: 0171-9335 PMID: 385321 Document Number: 141650
The cytoskeletal elements of the epithelial cells from rat intestinal mucosa were examined by immunofluorescence microscopy using antibodies to prekeratin, vimentin, desmin and actin and by EM. In both absorptive and goblet cells antibodies to prekeratin revealed an impressive and complex skeleton of fibrillar arrays of intermediate-sized filaments. These arays were not stained by antibodies to desmin, which stained intestinal smooth muscle, or by antibodies to vimentin, which reacted with filaments present in mesenchymal cells of the lamina propria. The skeletal arrays decorated by antibodies to prekeratin were resistant to treatment with Triton X-100 and high salt buffer and consisted of tonofilament-like structures, including desmosome-attached tonofibrils. The intermediate-sized filaments were not found in the microvilli, but cytokeratin filaments were especially concentrated in the terminal web and in a special zone subjacent to the terminal web, demarcated by a ring of desmosomes, all strongly decoratable with antibodies to prekeratin (apical skeletal disc). The central cytoplasm was filled by a 3-dimensional meshwork of cytokeratin fibrils, excluding the nucleus and, in the case of the goblet cells, the thecal region containing the secretory granules. This 3-dimensional meshwork of cytokeratin-containing filaments was continuous with.sbd.and inserted at.sbd.the apical skeletal disc, including the desmosomes on the apical side, and another dense aggregate of cytokeratin filaments located at the base of the cells. The overall architecture of cytoskeletal arrays of intermediate-sized filaments is seen in a cell present in a tissue. Normal epithelial cells contain a complex system of cytokeratin filaments which is involved in the establishment and maintenance of the specific polar organization of these cells.