"Nanoscopic Lipid Organization in Model and Bacterial Membranes"
Dr. John Katsaras (ORNL)

Biomembranes are the active boundary between cells and their surroundings. They are sophisticated and dynamic machines that perform a diverse array of functions, including selective transport, localization, communication and recognition, to name a few. It is also widely accepted that the plasma membrane is laterally heterogeneous containing nanoscopic regions enriched in certain types of lipids, which have different physical properties from the surrounding lipids [1]. These functional domains, commonly referred to as rafts, have been implicated in a wide range of cellular functions, including signal transduction, drug uptake, and interactions with pathogens. In recent years, we have used small angle neutron scattering to study nanoscopic lipid domains in model membrane systems [2-4], and more recently in the Gram-positive bacterium Bacillus subtilis. Data from these studies will be presented, including evidence for the existence of lipid nanodomains in a living prokaryote system, implying that lipid organization is a feature that has likely evolved over time, eventually becoming an integral property of biological membranes.

1.     Simons, K. et al. Nature 387, 569 (1997).
2.     Heberle, F. A. et al. J. Am. Chem. Soc. 135, 6853 (2013).
3.     Heberle, F. A. et al. J. Am. Chem. Soc. 135, 14932 (2013).
4.     Nickels, J. D. et al. J. Am. Chem. Soc. 137, 15772 (2015).

John Katsaras received his undergraduate degrees (BA, BSc) from Concordia University (Montreal, QC) and graduate degrees (MSc, PhD) from the University of Guelph. Currently he is senior scientist and Distinguished R&D Staff at Oak Ridge National Laboratory (ORNL). Prior to joining ORNL, John was Principal Research Officer at the National Research Council of Canada. He is internationally recognized for scientific contributions to the field of membrane biophysics, and for the development and applications of neutron and x-ray scattering techniques to biologically relevant systems.  

He is the guest of Dr. Peter Pawalek