Our cover image for the March 21 issue of Biophysical Journal shows phase-separated membranes of an organelle (the vacuole, or lysosome) inside of living yeast cells. In our paper, we tell the scientific story behind the image. Here, I’d like to share the story of the people behind the image.
Several years ago, my lab teamed up with our wonderful University of Washington (UW) colleague Alex Merz to study Saccharomyces cerevisiae, the yeast used to make bread and brew beer. When the yeast deplete their environment of certain nutrients, they shift from exponential growth to a quiescent state called “the stationary stage.” When this shift occurs, the membrane of the vacuole phase separates, and this transition is reversible! The phase-separated membranes are visually stunning. Sometimes the membrane contains only one large, circular domain of each phase, sometimes a few domains, and a lattice of smaller domains. We could image the larger domains on fluorescence microscopes in Alex’s lab, but to see the smallest domains shown on our cover image, we benefitted from the generosity of our UW colleagues Linda Wordeman and Josh Vaughan, who gave us access to microscopes capable of highly inclined and laminated optical sheet illumination, deconvolution microscopy, and structured illumination microscopy. The images on the cover were taken by Alex and then assembled by a graduate student, Glennis Rayermann, into a collage.
The next step in the story is that two graduate students in the lab, Caitlin Cornell and Chantelle Leveille, discovered that yeast regulate this transition in accordance with their growth temperature. But how? What change occurs in a vacuole that allows its membrane to phase separate? We thought the answer must lie in the lipidome of the membrane, but we were hesitant to jump into experiments. We had read that it was difficult to separate vacuoles from other organelles, especially lipid droplets.
While we were pondering how to solve that problem, Chantelle and Caitlin presented their preliminary results about yeast growth temperatures in posters at a Biophysical Society Annual Meeting. I remember Ilya and Kandice Levental stopping by the poster once, and then circling back again, and then again. Finally, one of them said, “Do you know Robert Ernst? He is at this meeting!” No, I hadn’t ever met Robert—he lives nine time zones away from my home in Seattle. We needed an international conference like the Biophysical Society Annual Meeting to bring us together. The Leventals knew that Robert was developing immunoisolation methods for extracting high-purity membranes from organelles of yeast. To make a long story short, Caitlin and Chantelle traveled to Germany to work alongside John Reinhard, an outstanding graduate student in Robert’s lab. We gave our subsequent lipidomics paper co-first authors and co-corresponding authors because we valued the different skills that everyone brought to the collaboration.
I feel as though the title of this blog post could have equally been “Why I love the biophysics community,” or “Why it is worth presenting unpublished preliminary results at conferences,” or “Why poster sessions at Biophysical Society meetings are so great.”
So, why do I love the biophysics community? Because overall, biophysicists are supportive of each other, like when our colleagues gave us access to their beautiful microscopes or when the Leventals went out of their way to connect my lab to the Ernst lab. Moreover, the Biophysical Society has a commitment to improving the culture of science through initiatives like an anti-harassment policy in their code of conduct, the JUST-B poster session, and the Inclusion and Diversity and Professional Opportunities for Women committees.
Why is it worth presenting unpublished results at conferences? When deciding whether to present preliminary results, many scientists focus on the risk of being scooped, which, to be fair, is not zero, in my experience. But there’s also a risk associated with not presenting our early results—we might miss out on connections and feedback that could propel our research in new directions.
Why are poster sessions at Biophysical Society Annual Meetings so great? Because you can stand next to your poster for the entire day having deep, lengthy conversations with other researchers, which can lead to meeting scientists from around the world. See you at next year’s posters!
—John Reinhard, Chantelle L. Leveille, Caitlin E. Cornell, Alexey J. Merz, Christian Klose, Robert Ernst, and Sarah L. Keller