Hideki Nakamura


Cells are the smallest unit of life that make up our body. However, a single cell is not just a single compartment; it is further divided into even smaller subcompartments, each of which is specialized in a certain biological function that enables the cell to maintain life. Among these various subcompartments, dropletlike organelles (also referred to as biomolecular condensates in recent reports) have been drawing more and more attention. They are rather newly discovered, the most dynamic class of subcellular compartments, whose behavior resembles that of liquid droplets or hydrogels. Without the surrounding lipid bilayer membrane, they can be assembled and disassembled within a relatively short period of time. These dynamic features are thought to be critical for the organelles for proper spatiotemporal regulation in a wide variety of biological contexts, including gene expression and stress response in many pathophysiologies. However, the mechanism of assembly and disassembly of the dropletlike organelles is unknown, in part due to the lack of techniques that can perturb the processes. Therefore, I developed a technique, iPOLYMER, that can manipulate the assembly of dropletlike organelles in living cells by chemicals or light irradiation. For this purpose, I used techniques in the synthetic biology field to induce sol-gel phase transition, one of the physicochemical mechanisms that have been related to the assembly of dropletlike organelles. Using iPOLYMER, I succeeded in synthetically mimicking stress granules, a well-known example of a dropletlike organelle, in living cells. These results suggested that sol-gel phase transition can be the underlying mechanism that regulates the assembly of the organelles. Furthermore, the results clearly demonstrated that iPOLYMER is a promising tool to elucidate the regulation of the dropletlike organelle assembly. Development of iPOLYMER can thus open up a new era in the research on dropletlike organelles, providing profound insights into both physiological and pathophysiological processes.

The research was done in the Takanari Inoue lab (Department of Cell Biology, Center for Cell Dynamics).

Questions & Answers

Why did you choose Johns Hopkins for your work? In my previous lab, I was a collaborator with my current lab (Takanari Inoue). As a collaborator, I could feel the energy and open-mindedness of the labs at Johns Hopkins, which attracted me most when I was planning the next step in my career. What does receiving this award mean to you personally and professionally? Do you have any connection with the particular award you received? The award means a lot to me both personally and professionally. Personally, being awarded, I finally feel as if I’m becoming more well-adjusted to the research culture in the U.S., away from my homeland, Japan. The transition has been largely painless due to the people around me, especially my family, my principal investigator (Takanari Inoue) and all the lab members. Despite this, the decision to move abroad to pursue a postdoc is one of the more significant decisions I have personally had to make. Although the award, in name, is for research, it also marks an important milestone for me in my own personal journey. On the professional front, the award is an enthusiastic support for my own approach to biology. I have been in the field of synthetic biology, which aims to synthetically manipulate various biological processes by developing various rationally designed tools. Although not widely accepted at the moment, the award is an important symbol of encouragement that synthetic biology, although relatively young, is a promising field. What contributed to your project's success (special skills, interests, opportunities, guidance, etc.)? First of all, excellent work by Albert A. Lee, a visiting student who performed many of the experiments that established the story of the current research, laid the foundation for success. Without his enthusiasm and hard work, on top of all the support from other lab members, it would have been almost impossible for me to get this research done. From my side, my academic background probably helped me a lot. I majored in nonlinear physics as a student, and then moved to biological research after getting my Ph.D. Since then, I belonged to several labs with different disciplines, such as molecular biology, biochemistry, fluorescence imaging, electrophysiology and synthetic biology. The experiences in those various research fields helped me get through all the difficulties, directly and indirectly. Last, but not least, patient and insightful mentoring by my principal investigator, Takanari Inoue, guided me through this academic journey. I have been impressed by his vision and logical way of thinking all through the research, and I think I learned so much through my discussions with him. What thoughts do you have about Young Investigators’ Day itself, as a celebration of the roles student and fellows play in research at Johns Hopkins? I think Young Investigators’ Day provides many students and fellows with a good motivation, and I am no exception. Also, it gave me an opportunity to reconsider the broader appeal of my research, which is a point of view often overlooked. What has been your best/most memorable experience while at Johns Hopkins? I have been enjoying the time I spend in the lab, doing experiments, having discussions and chatting with my lab mates. Although we have had many fun activities outside the lab, that would be the best experience for me. What are your plans over the next year or so?  I am now trying to get another project to be published. In parallel, I have started searching for faculty positions. Tell us something interesting about yourself that makes you unique. Do you have any special hobbies, interests or life experiences? I like reading books and watching sports. I also enjoy scuba diving, but I haven’t had many chances to dive recently. I often dream to do some research on muscle physiology during the exercise or on physiology during diving someday so that my hobbies can be beneficial for my professional career.