The intestine is the location of diseases of enormous social and economic impact, like the inflammatory bowel disease (affecting about 1 person in every 500 in the UK) and the colon carcinoma (the second most frequent malignancy in developed countries). In addition numerous infectious agents use the intestinal tract to gain access into the body. The intestine therefore fulfils an important mechanical and immunological barrier function. Alterations of this barrier count among the diverse factors that predispose to the development of conditions that affect the intestine. Understanding how the intestinal barrier develops and maintains its integrity is key to prevent those diseases. An important component of the intestinal barrier are the epithelial cells, which constitute the largest cell population of the intestine and bear a so called brush border. The brush border is a complex anatomical structure whose assembly is still not well understood. We will use a cell line with characteristics of intestinal epithelial cells to investigate the consequences of altering the components of the brush border. By doing so we will learn about the assembly of the intestinal barrier and the consequences of its disruption for the development of inflammatory bowel disease and other conditions.