The animal body is made up of numerous cells. Dr. Takeichi was investigating how animal cells stick together to form tissues and organs, and identified a key protein which he named ‘cadherin’. Cadherin is present on the surface of a cell and binds to the same cadherin protein on the surface of another cell through like-like interaction, thereby binding the cells together. Without cadherin, cell to cell adhesion becomes weakened and leads to the disorganization of tissues. Dr. Takeichi found that there are multiple kinds of cadherin within the body, each of which are made by different cell types, such as epithelial and neuronal cells. Cells with the same cadherins tend to cluster together, explaining the mechanism of how different cells are sorted out and organized to form functional organs.
Further studies by Dr. Takeichi’s group showed that cadherin function is supported by a number of cytoplasmic proteins, including catenins, and their cooperation is essential for shaping of tissues. His studies also revealed that the cadherin-dependent adhesion mechanism is involved in synaptic connections between neurons, which are important for brain wiring.
The discovery of cadherins, which are found in all multicellular animal species, has allowed us to interpret how multicellular systems are generated and regulated. Loss of cadherin function has been implicated as the cause of certain cancers, as well as in invasiveness of many cancers. Mutations in special types of cadherin result in neurological disorders, such as epilepsy and hearing loss. The knowledge of cadherin function is expected to contribute to the development of effective treatments against such diseases.