Professor Ko Jae-won’s research team (Department of Biochemistry, College of Life Science and Biotechnology) discovered that the MDGA protein, one of the proteins which control the neuron’s movement during the initial stages of the brain, regulates the structure and function of synapse during the adult stage of the brain. The team’s study demonstrated that the MDGA protein interacts directly with a synapse adhesion protein called neuroligin-2. Their study was published in the online version of the Proceedings of National Academy of Sciences of the United States of America (IF 9.681) on December 18th. The synapse, the most basic unit that operates the brain’s functions, is also where two different nerve cells meet and the neurotransmitter occurs. While the synapse consists of two types—excitatory and inhibitory, the two seek effective neurotransmission by pursuing balance. When such balances break, various brain diseases are known to occur. The neuroligin-2 protein is known as a characteristic of the postsynaptic membrane, and to play a primary role in maintaining the function of inhibitory synapse, generating cell adhesion with the neurexin in presynaptic membrane. In the study led by Professor Ko, the MDGA protein has been found to directly interact with neuroligin-2 in postsynaptic membrane and to selectively impede the synapse adhesion with neurexin. According to the findings, the MDGA protein specifically combines with neuroligin-2; and when the neural cultured cell excessively manifests MDGA protein, the number and function of inhibitory synapse reduces. Also, when the MDGA protein decreases, the number and function of inhibitory synapse selectively increases; and such changes in the structure and function of inhibitory synapse are selectively controlled according to the neuroligin-2’s express level. Unlike most proteins that promote the creation of synapse, the MDGA protein appears to selectively impede the function of inhibitory synapse adhesion protein and covertly control the structure and function of inhibitory synapse. Interestingly, recent studies on genetics have suggested that the MDGA protein is related to mental illnesses such as autism and schizophrenia. Professor Ko highlights that “The study underlines both the need for a new direction in the molecular neurobiology field which has focused on excitatory synapse and the possibility for a new perspective on the underlying pathogenesis in mental illnesses.” He adds that “Following studies will investigate the pathogenesis of related mental diseases and provide more basic knowledge for their treatment.”