[No. 21] Ryohei Yasuda

Spring in Long Island, New York, is beautiful. When the long, dark winter ends, the daylight hours suddenly lengthen, and flowers begin to bloom all at once. Just as you notice the pale green leaves emerging, they quickly transform into a lush, dense forest. In this spring, when all the plants begin to grow in unison, everything seems vibrant and alive. People, too, seem to be in high spirits, enjoying the season by cycling and walking around. Before I knew it, this is the fifth spring my family and I have experienced since coming to Cold Spring Harbor Laboratory here on Long Island. This will also be our last spring in Cold Spring Harbor, as we are scheduled to move to Duke University Medical Center in North Carolina this July. While I am tired of the long winters and happy to be moving to the warmth of North Carolina, I also feel a little sad to think that this is the last time I will see this beautiful spring.

At Cold Spring Harbor Laboratory, I work as a postdoctoral researcher, peering into the synapses of nerve cells with a microscope to study the molecular mechanisms of memory. Some people might wonder why someone like me, who graduated from the Department of Physics, is doing research on nerves. However, biology today actually requires the concepts of physics, and the so-called "biophysics" is a hot field. My encounter with biophysics was the result of a single lottery draw when I was still a student at Keio University. At Keio's Department of Physics, they use a lottery to assign students to laboratories for their graduation research when there are too many applicants for a particular lab. Having the fixed idea that physics meant particle physics, I initially applied for theoretical physics but lost in the lottery. I continued to lose in subsequent lotteries and ended up in my 10th choice out of 10 labs: the biophysics Kinoshita Lab. Of course, the reason I am still in biophysics is that I was deeply moved by the "movement of biological molecules" I witnessed in Kazuhiko Kinoshita's lab (Professor Kinoshita is now a professor at the Faculty of Science and Technology, Waseda University). For me, the phrase "fortunate bad luck" perfectly describes this lottery in the Department of Physics, which I hear is still being conducted today.

Now, biomolecules are what lie at the very boundary between life and matter. If you break down living organisms into smaller and smaller parts, you eventually get to atoms. Atoms are not alive... I think. So what about molecules, the next level up? Living organisms have macromolecules, and some of them can move on their own. In fact, watching a string of actin, a muscle molecule, wriggle around on another muscle molecule called myosin spread on a glass surface looks exactly like an earthworm crawling. How does it move? The study of these so-called "molecular machines" fascinated me. Then, in graduate school at Keio, I proved that a single molecule called ATP synthase is a rotary motor. This series of works became world-famous, and in the year we made this discovery, the proponents of this rotation theory received the Nobel Prize. So, when I boast about this work, I say, "It was Nobel Prize-level work." It's undeniable that it contributed significantly to their Nobel Prize, so it's not really a lie.

After finishing graduate school, I decided to change fields again and study the behavior of molecules inside the brain's nerve cells. Each individual molecule can do surprisingly complex things, but it is ultimately just a single component. I wanted to see how these components assemble to create the activities of life. Since nerves are responsible for our "mind," I vaguely thought it would be wonderful if I could connect the "mind" and "molecules." Changing fields comes with some risks. You have to build up your credentials in that field from scratch, and your knowledge in that area is limited. However, there is also the possibility of bringing a new perspective to the field. So, I ended up in the lab of Karel Svoboda at Cold Spring Harbor Laboratory, who has a similar background to mine—from the Department of Physics to molecular motors to neuroscience—to investigate how molecules in synapses interact.

Around the time I completed a phase of my research on calcium channels at Cold Spring Harbor, I decided to look for an assistant professor position in the United States. At American research institutions, when you move from a postdoc to an assistant professor, you immediately get your own independent laboratory and can conduct independent research. Also, having changed fields shortly after coming to America, I calculated that it would be easier to find a position in the US. In the end, this job search was successful (for details on this process, please see my homepage), and starting this July, I will be leading a lab at Duke University Medical Center. One of my goals is to quantitatively elucidate the behavior of molecules in neural synapses.