Abstract
The localization of proteasomes (multicatalytic protease complexes) in human intestine was studied immunohistochemically.
Positive staining for proteasomes was seen in absorptive epithelial cells, connective tissue cells in the tunica propria, smooth muscle cells in the lamina muscularis mucosae and the muscle layer, endothelial cells and nerve cells. A positive reaction was seen in the nuclei of the crypt cells, which were growing, and in the cytoplasm of the epithelial cells of the upper half of intestinal villi of the small intestine and the cells facing the intestinal cavity of the large intestine, which were not growing.
These findings show that proteasomes are widely distributed in various types of cells suggesting that these protease complexes have essential roles for cell viability. Their intracellular localization suggests that they may be involved in cell growth and differentiation.
