Biophysical Society Newsletter - August 2016





Biophysical Journal Know the Editors Kazuhiro Oiwa National Institute of Informa- tion and Communications Technology, Tokyo Editor, Molecular Machines, Motors, and Nanoscale Biophysics Q: What are you currently working on? Our research group has focused on understand- ing the mechanisms of dyneins and eukaryotic flagellar motility. Dyneins are microtubule-based protein motors that drive cilia/flagella, and play important roles in a variety of essential intracel- lular motility. Using in vitro motility assays and single-molecule measurements, we have revealed mechanical properties and regulations of axo- nemal and cytoplasmic dyneins. Recently, we adopted a bottom-up approach for our study on dyneins and axonemes, in which well-character- ized components are combined into a functional assembly in order to reconstitute the original functions in vitro. Advances in nanotechnology, including DNA origami techniques, and in mo- lecular biology make this approach feasible. Q: What are you currently working on that excites you? Collective motion of self-propelled particles is my current interest. We found that microtubules driven by surface-bound dyneins self-organized into large-scale vortices. When I was observing microtubule movement in a small 100 μm × 100 μm area, large streams of microtubules acci- dentally passed through the observation area. That was my first encounter with the phenomenon. Like the Nazca geoglyphs, a wide view enabled us to recognize the large-scale vortex patterns formed in an entire flow cell. We successfully showed this process by a simple mathematical model, based on only the smooth motion of single microtubules and their local interaction (alignment of micro- tubules on collision). Now, it is exciting for us to extend the experiments to various types of dynein Kazuhiro Oiwa

in order to find a universal class of collective motion.

Q: What has been your most exciting discovery as a biophysicist? My most exciting discovery was the large configu- ration change of an axonemal dynein molecule coupled with nucleotide states. This was done in collaboration with a group at the University of Leeds. On electron micrographs, single particle analysis of negatively stained axonemal dynein revealed such large changes. From this work, I learned that raw micrographs of negatively stained molecules contain a wealth of structural informa- tion, and I fully recognized the power of math- ematics. Q: At a cocktail party of non-scientists, how would you explain what you do? Talking about the invisible things that happen inside of our bodies is a good way to capture peo- ple’s interest. First, I would ask the non-scientists when and how symmetric breaks take place in our body during development. Then I would explain that a simple function of a group of tiny organ- elles, called cilia, determines the development of right–left asymmetry. This is a good introduction to present to my audience, to explain to them the importance of studying these organelles. It is also an amazing example of our extraordinary biologi- cal system, in which a small bias can be detected, enhanced, and bring about change in a wide ranges of scales. This is an attractive concept, not only for scientists, but also for non-scientists. My main way of staying up to date with the latest research is to attend the Biophysical Society An- nual Meeting and other international conferences. Conferences are not only showcases of the latest research, but they also provide rich sources for novel ideas. Also, reading peer-reviewed literature is, of course, unavoidable. My preference is the review journals since they are handy for catching up with the progress in the research fields. Q: How do you stay on top of all the latest developments in your field?

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