Brush-border and cell-adhesion of insect enterocytes have basic similarities with those of vertebrates

The molecular architecture of the brush border (BB) cytoskeleton of the vertebrate intestinal cells results to be well defined in its components. From the comparison of the protein profiles of chicken and larval BB extracts of Manduca sexta (Insecta, Lepidoptera) it emerges that cytoskeletal major components are the same and they have a similar localization in immunolabeled tissues. The smooth septate junctions (SSJs) of the midgut cells are localized in the most apical regions, where vertebrate intestinal cells exhibit the zonula occludens. We demonstrate that alpha-actinin, vinculin and myosin II are involved in the actin filaments-SSJ interaction. The insertion of microfilament bundles into submembranous F-actin/alpha-actin/vinculin complexes, discovered and described almost exclusively in vertebrate junctions of adherens type, results to be a more general system including the insect SSJs, that we have analyzed