Molecular mechanisms and roles of organelle interaction :

Various biochemical reactions occur cooperatively within cells. As a result, each cell is autonomously maintained and exhibits specific functions. Many of these intracellular biochemical reactions do not occur just anywhere in the cell, but take place in organelles within the cell, such as mitochondria, endoplasmic reticulum, and lysosomes. Therefore, the transport of substances and signal transmission between organelles are extremely important for these biochemical reactions to work in harmony.

For a long time after organelles were discovered, it was thought that each organelle existed independently within the cell. However, recent research has revealed that organelles actually physically approach each other and exchange substances and signals.

We are researching to elucidate the molecular mechanisms and roles of this newly understood inter-organelle communication, particularly the contact between the endoplasmic reticulum and mitochondria.

Mechanisms underpinning the functioning of neurons :

The function of the brain is exhibited by neurons forming a network and sending signals through neurotransmitters. Within each neuron, the “processing” of signals received from other neurons takes place, fulfilling its role as a neural circuit element. However, much is still unclear about how this complex signal processing is carried out.

We are researching the role of organelles in this signal processing. When observed with electron microscopy, organelles in each neuron have unique shapes and arrangements, and the structure greatly differs depending on the compartment of neurons. By clarifying the meaning of this, we want to understand how our brain has such advanced functions.

Mechanisms involved in the formation and maintenance of neuronal circuits:
Neurons in mammalian brain have cell bodies that are a few tens of micrometers in size (about the thickness of a hair), whereas they extend very thin processes sometimes up to several centimeters away to other neurons to form neural circuits. It is believed that the formation and maintenance of such structures require highly complicated but intricate mechanisms, which remains largely unexplored. We are studying the role of organelles in the mechanisms of neural circuit formation and maintenance. We are studying molecular and biochemical mechanisms underlying the complex but tightly regulated neuronal functions.

Nanoscale ultrastructures of neurons:
Our understanding of nanometer-scale structures that make up cells remains very limited due to the lack of techniques to observe them. We developed a unique technique to label specific structures of cells under the electron microscope. Combined with a deep learning method-based analysis, we will reveal 3D-ultrastructures of cells, including neurons.

Adult neurogenesis :
Adult neurogenesis plays a key role in the formation of memories. However, the mechanism regulating the amount and timing of neurogenesis in the adult brain remains to be elucidated. We will reveal the mechanism regulating the differentiation of adult neural stem cells to neurons.