Student Hosted Colloquium

Thursday, April 5th
Professor Sarah Keller
"Seeing Spots: Liquid domains in Lipid Membranes"

4:15pm - 5:15pm
Braun Lecture Hall
S.G.Mudd Chemistry Building
Stanford University




This seminar is free and open to the public. All Stanford University Chemistry students are encouraged to attend this special event.

About the Seminar:
We study giant lipid vesicles as a model of cell membranes. Much of our past work has focused on finding the minimum number of lipid types required to create liquid domains in a vesicle. We find that liquid domains appear on the surface of vesicles containing at minimum three membrane components: a high melting temperature lipid, a low melting temperature lipid, and cholesterol. These three components separate into two phases. This presents an interesting question of which components are in which phases, and in what amounts. I will review our work using fluorescence microscopy and NMR to determine the lipid composition of the liquid domains vs. the background, and to map phase diagrams, and to quantify tie-lines. Our work in the past year has focused on two new projects. We study how domains diffuse across the two-dimensional vesicle surface. We also study if domains in one leaflet of the membrane can induce the formation of domains in an opposite, initially uniform leaflet, or if the uniform leaflet suppresses domain formation in the first leaflet.

About Keller:
Professor Sarah Keller is a faculty member of the Chemistry Department at the University of Washington in Seattle. Professor Keller received her phD from Princeton University where she worked with Sol Gruner and studied how the lipid composition of a membrane may altered the activity of an ion channel using voltage-clamping and x-ray scattering techniques. She was a post-doc with Joe Zasadzinski at the University of California at Santa Barbara where she studied various membrane and surfactant systems with electron microscopy. Her interest in membranes and lipids then led her to a second post-doc here at Stanford University working with Harden McConnell. Here, she studied lipids in monolayers; in particular, how the miscibility critical point and the propensity for complex formation depend on lipid composition. Professor Keller became a faculty member at University of Washington in 2000 and is the receiver of many honors and awards including the Margaret Oakley Dayhoff Award from the Biophysical society, the Cottrell Scholar Award, and NSF CAREER Award.

Questions
Please contact Patricia Dwyer at 650-723-4770.