Model Membranes, Living Organisms and Lateral Membrane Organization

Speaker

John Katsaras, ORNL

Abstract

Biological membranes are the active boundary between cells and their surrounding environment. Membranes are sophisticated and dynamic assemblies 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, whose physical properties differ from the surrounding lipids [1]. These functional domains have come to be known as rafts, and have been implicated in a wide range of cellular functions including signal transduction, drug uptake and interactions with pathogens. We have used different neuron scattering techniques to study the lateral organization of membranes and their associated dynamics [2-4]. More recently, we have studied the plasma membrane of the Gram-positive bacterium Bacillus subtilis. Data from model and living systems 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).