Role of the Cytoskeleton in Intestinal Absorptive Function and Receptor Expression in the Cells

摘要

The objective of this series of investigations was to explore and define the roles of the cytoskeleton apparatus in the function and tranport of solutes across the intestinal epithelium. Most epithelial cells, including the intestinal enterocyte and the mucin-secreting goblet cell are now known to possess a highly ordered cytoskeletal matrix comprised of microfilaments, intermediate filaments and microtubules. Macromolecular aggregates such as actin and a variety of related proteins are present in the amplification structures, i.e. microvilli of the mucosal surface. This component of the system was perturbed by the application of Cytochalasin B (CB), a macrolide antibiotic which interacts with mechanochemical proteins of microfilaments. Studies from a number of laboratories suggest that these cytokinins inhibit the rate of actin filament polymerisation and disrupt actin-based networks in a very dynamic manner. Work performed on this contract provides evidence that microfilaments and/or microtubules may be critical physicochemical transducers in the sequence of events leading to 1) transmural absorption of salts, organic solutes and osmotically-linked fluid flow; 2) mucin secretions by the goblet cells, which constitute approximately 20-30% of the surface cell population; 3) the expression of Beta receptors HeLa cells by butyrate treatment is preceded by a dramatic reorganization of the intracellular cytoskeleton.