In memoriam: George Oster, UC Berkeley, 1940–2018

George Oster, professor of Cell and Developmental Biology at the University of California, Berkeley, died on April 15, 2018. His death is a true loss for the biophysics, mathematical biology, and applied mathematics communities. A pioneer in these fields, George fostered our understanding of biological molecules, cells, and tissues as mechanical machines. After finishing high school on Long Island, NY, in 1957, George attended the U.S. Merchant Marine Academy at Kings Point, NY, and spent a year at sea. In 1961, he continued his studies at Columbia’s graduate school and received a PhD in nuclear engineering. At the end of his PhD, George realized that science attracted him more than engineering and he pursued another degree, in biophysics. Shortly after that, he met Aharon Katchalsky, a pioneering Israeli scientist, who saw George’s talent and persuaded him to work together with him on the thermodynamics of biological networks. With Katchalsky, George did his postdoctoral work at the Weizmann Institute in Israel and also at the University of California, Berkeley. George fell in love with the vibrant political and scientific scene of the Berkeley campus in the late 1960s but also with the natural beauty of the Bay Area. He stayed at Berkeley as a faculty member for the rest of his life, changing departments as his insatiable curiosity drove him from one biological problem to another. George was very fortunate to be a part of a great generation of scientists who had the audacity and freedom to move between disciplines. Early in his career, he worked on pathbreaking mathematical models of population dynamics and developed the first detailed theories of caste evolution among social insects (with Edward Wilson) and theories of bifurcations to a hierarchy of periodic oscillations and chaos in simple ecological models (with Robert May). At some point in life, every great scientist discovers a unique point of view that reveals a hidden natural order that was previously unknown. George made his discovery in the late 1970s–early 1980s, when he realized that biological molecules, cells, and tissues can be seen as peculiar mechanochemical machines, in which mechanical forces, chemical reactions, and stochastic Brownian movements are intimately coupled. For the next 35 years of his remarkable career, George unraveled the laws of this mechanochemical coupling, which led to an understanding of the physics of the cell. With Garrett Odell, James Murray, and others, George pioneered mechanical models of morphogenesis. These models revealed how forces and deformations of the cell cytoskeleton integrate with chemical and genetic signals to shape tissues in the development of organisms. With Alan Perelson, George proposed that the swelling of the cytoskeletal gel can drive protrusions at the cell front, laying the foundation for quantitative studies of cell motility. From populations, to tissues, to individual cells—George did not stop there. Next, he looked at molecular motors–peculiar and fundamentally important proteins moving on polar cytoskeletal fibers and exerting forces on a piconewton scale. George realized that these biological machines operate in a realm that is dominated by thermal fluctuations, and that nature found a way of turning thermal noise into a unidirectional, ratcheted Brownian motion through physical–chemical reactions that generate forces and movements. This discovery led to a dramatic breakthrough in our understanding of how energy transduction occurs in all living organisms. In the 1990s, George together with Charlie Peskin and his students, postdocs, and experimental collaborators, made another breakthrough: he discovered how to go from abstract ratchet models to mechanochemical models by using structural, biochemical, and genetic analyses of molecular motors. During this decade, George established an important shift from conceptual to detailed DOI:10.1091/mbc.E18-04-0235 *Address correspondence to: Alexander Mogilner (mogilner@cims.nyu.edu). © 2018 Mogilner. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0). “ASCB®,” “The American Society for Cell Biology®,” and “Molecular Biology of the Cell®” are registered trademarks of The American Society for Cell Biology. Alexander Mogilner* New York University, New York, NY 10012