How membranes help cells do their jobs
In the Middle Ages, cities were protected and defined by their walls. Likewise, in our bodies, cells and many of their sub-compartments are surrounded by membranes. However, instead of being solid and rigid like a stone wall, the membranes of cells are soft and dynamic. The building blocks of the membranes – the lipids and proteins – rapidly exchange places with their neighbors. Moreover, cells are constantly making new or different types of building blocks and inserting them into their membranes.
In her 2023 Sverdrup Visiting Scientist lectures, Dr. Sarah Keller, a professor at the University of Washington-Seattle, will discuss how the dynamicism of membranes can be both a bane and a boon for cells. Very soft and dynamic membranes can rip or disintegrate. This would have been a problem for the most ancient cells on the Earth. On the other hand, movement of lipids within membranes can help cells react to their environment. This is a huge advantage for modern cells every day.
The earliest versions of cells on Earth could have been very simple: a membrane that encloses molecules to encode information, like DNA, and to perform tasks, like proteins. However, the very simplest membranes are typically not stable in salty environments like oceans. How could those early cells have survived?
Bread, Beer, and Hungry Yeast
During the process of making bread and beer, yeast cells eventually run out of sugar to eat. They react by segregating certain lipids and proteins in one of their membranes. Under the microscope, this membrane appears break out in polka-dots.
In her Convocation Lecture on Monday, April 10, titled “Membranes of Hungry Yeast are Tiny, Living Thermostats,” Keller will discuss how yeast membranes acquire the polka-dots, how the transition can be reversed, and how yeast control the transition.
Protocells on Fragile Membranes
The earliest versions of cells on Earth could have been very simple: a membrane that encloses molecules to encode information, like DNA, and to perform tasks, like proteins. However, the very simplest membranes are typically not stable in salty environments like oceans. How could those early cells have survived?
In her Convocation lecture on Tuesday, April 11, titled “Stabilizing fragile membranes on the early Earth”, Keller will explain that small building blocks of DNA and proteins can interact with membranes, stabilizing them. In turn, these interactions have the potential to concentrate the building blocks on the surface of the membrane, helping them link up into larger molecules capable of other important jobs.
Event Schedule
Monday (April 10, 2023) – “Membranes of Hungry Yeast are Tiny, Living Thermostats”
Tuesday (April 11, 2023) – “Stabilizing Fragile Membranes on the Early Earth”
Biography:
Sarah Keller, the Duane and Barbara LaViolette Professor of Chemistry, is a Biophysicist at the University of Washington in Seattle. She investigates self-assembly, complex fluids, and soft matter systems. Her research group’s primary focus concerns how lipid mixtures within bilayer membranes give rise to complex phase behavior. She is an elected member of the Washington State Academy of Sciences and a Fellow of the American Physical Society, a Fellow of the AAAS, and a Fellow of the Biophysical Society.
Additional information on her work:
- Ed Yong – The Atlantic “A New Clue to How Life Originated”, Aug. 12, 2019.
- Physics Today “Why does biophysics attract a disproportionate number of women?”, 2021.
Sponsored by the General Leif J. Sverdrup Visiting Scientist Program at Augsburg University.