Professor Veatch’s research investigates how the physical properties of lipid mixtures influence cellular processes occurring on the surface of mammalian cells. Lipid bilayer membranes containing cholesterol can support two coexisting liquid phases, and there is evidence that the presence of a miscibility phase transition impacts the organization and function of membrane proteins. Further, we hypothesize that the cell membrane is poised in a one phase region near a miscibility critical point, and equilibrium composition fluctuations associated with this critical point contribute to cellular functions. We are currently testing this hypothesis using a wide range of experimental and theoretical approaches, in both model systems and intact cells. In one class of experiments, we probe how lipid organization is influenced by rearrangements of membrane proteins, primarily using newly developed ‘super-resolution’ fluorescence imaging techniques. In other experiments, we manipulate cellular functions using targeted perturbations of membrane heterogeneity. Experimental and theoretical work in model systems is aimed at generating predictions regarding how criticality could influence cellular processes. Our long term goal is to discover novel biophysical mechanisms of protein regulation through lipids, allowing for a deeper physical understanding of complex biological processes and new avenues for exploring treatment strategies for some human diseases.
Liquid General Anesthetics Lower Critical Temperatures in Plasma Membrane Vesicles. (E. Gray, J. Karslake, B. B. Machta, and S. L. Veatch), Biophys. J. 105(12), 2751-9 (2013).
Distinct Stages of Stimulated FceRI Receptor Clustering and Immobilization Are Identified through Superresolution Imaging, (S. Shelby, D. Holowka, B. Baird, and S. L. Veatch), Biophys. J. 105(10), 2343-2354 (2013).
Adhesion Stabilizes Robust Lipid Heterogeneity in Supercritical Membranes at Physiological Temperature (J. Zhao, J. Wu, and S. L. Veatch), Biophys. J. 104(4), 825–834 (2013).
Critical Casimir Forces in Cellular Membranes, (B. B. Machta, S. L. Veatch, and J. P. Sethna), Phys. Rev. Lett. 109(13), 138101 (2012).
Minimal Model of Plasma Membrane Heterogeneity Requires Coupling Cortical Actin to Criticality, (B. B. Machta, S. Papanikolaou, J. P. Sethna, and S. L. Veatch), Biophys. J. 100(7), 1668–1677 (2011).
Critical Fluctuations in Plasma Membrane Vesicles, (S. L. Veatch, P. Cicuta, P. Sengupta, A. Honerkamp-Smith, D. Holowka, and B. Baird), ACS Chem. Bio. 3, 287-293 (2008).