In animal multicellular organisms, epithelial cells are dynamic structures involves in a complex, exquisite and regulated series of physiological process, mainly those related to the absorption, catabolism and recycling of nutrients. These organisms are continually challenged by a variety of environmental hazards, and the fi rst line of defence, protection and exchange interface, is provided by epithelial cells. This review aims to describe the current information about the epithelial machinery of absorption and transport that makes possible the right response to environmental challenges that is the MegaCUBAM complex.