[이뉴스투데이 전한울 기자] DGIST announced on the 21st that a joint research team led by Professor Jae-Won Ko of the Department of Brain and Cognitive Science and Professor Won-Chan Oh of the University of Colorado, USA discovered a key signaling mechanism that orchestrates specific inhibitory synaptic activity in the brain neural circuit. It is expected to suggest a new research direction that can improve specific cognitive abilities.
Synapses control all brain functions by acting as a special window that transmits neural information quickly and accurately. Synapses are divided into excitatory synapses and inhibitory synapses.
Synapses work together to keep the neural network in balance so that brain functions can function normally. Numerous synapses in our brain are known to have various characteristics for each brain region and neural circuit. However, the molecular mechanisms that determine the unique properties of different neural circuits that perform similar functions within the same brain region remain largely unknown.
In this study, MDGA1 protein was overexpressed or deleted in CA1, a subregion of the hippocampus of adult mice, and reconfirmed that MDGA1 protein actually plays a negative role in inhibitory synapses.
In particular, it was found that the MDGA1 protein, which cannot bind to Neuroligin 2, still inhibits the development of inhibitory synapses, and that a specific site (MAM domain) whose function was not well known before is involved. This suggests the possibility that the MDGA1 protein operates in a way other than the previously proposed molecular mechanism.
Excitatory neurons in the CA1 region of the hippocampus receive different inhibitory signals from the cell body and dendrites, respectively. APP protein, expressed in inhibitory neurons, is a factor necessary for the normal operation of excitatory neurons by transmitting these two inhibitory signals. At this time, it was found that MDGA1 specifically orchestrates APP function only at the inhibitory synapses formed in dendrites.
They also found that when the balance of the MDGA1-APP complex is disrupted, inhibitory synaptic neurotransmission is abnormally altered, and the ability to recognize novel object memories in mice is also inhibited.
Meanwhile, for this research result, Jinhoo Kim and Seungjun Kim participated as co-first authors as co-first authors. The research results were published online on the 19th in the ‘Proceedings of the National Academy of Sciences of the United States’, an international academic journal.
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