The cleft contains gap junctions, tight junctions, desmosomes, and adheren proteins, all of which help to propagate and/or regulate cell communication through signal transduction, surface receptors, or a chemogradient. In order for a molecule to be taken into the cell either by endocytosis, phagocytosis, or receptor-mediated endocytosis, often that molecule must first enter through the cleft. The intercellular cleft itself is a channel, but what flows through the channel, like ions, fluid, and small molecules and what proteins or junctions give order to the channel is critical for the life of the cells that border the intercellular cleft.