Although there have been big advances in molecular biology and structural biology, we still cannot answer the very basic question “What is life?” We are approaching this question by imaging cellular processes at the single molecule level in living cells. For this purpose, we develop new technologies by ourselves ranging from microscope optics to probes. Using these new, original technologies, we are mainly focusing on the movement or the trafficking of proteins and other molecules in living cells, especially neurons. For example, we have been working on the regulation of the axonal transport in neurons. Motor proteins transport a variety of elements inside the cell. In fact, so important is this transport that it is not an exaggeration to describe it as the lifeline of a cell. When a motor malfunctions, the cell’s internal navigation system becomes disabled so that transport is compromised. We are studying the navigation system by directly observing transport using new imaging techniques and the motor protein kinesin KIF5, a key regulator for axonal development, as our model.
Despite neurons extending a large number of projections, only one becomes an axon. Recently, we have discovered that the structures of the microtubules on which kinesins travel in dendrites and the axon are different. KIF5 can recognize the structural difference between these microtubules and therefore be used to determine which neural projections become the axon and which become dendrites.
- Molecular mechanisms of intracellular transport and its regulation
- Development of microscope optics and probes for single molecule imaging and super-resolution imaging
- Visualization of cellular processes by single molecule imaging and super-resolution live cell imaging