Tobias Baumgart
Associate Professor
Graduate Chair

Overview

Physical and Biological Chemistry

Research

Research in the Baumgart group is largely centered on the physical chemistry of amphiphile membranes with lateral heterogeneity resulting from non-ideal mixing. Our aims include characterization of biologically relevant membranes including lipids and proteins, where we investigate both composition and shape (curvature) heterogeneity. Both of these aspects are thought to be highly relevant to the function of biological membranes. We focus on freely suspended, rather than solid supported membranes, with an emphasis on bilayer membranes, but we also include monolayer systems. We investigate membranes that laterally segregate into co-existing fluid phases, and are particularly interested in quantitatively understanding the phenomenon of line tension at the phase boundary. We also examine molecular details that govern the partitioning of functionally relevant protein constructs between coexisting membrane phases and thereby aim to contribute to enhancing the biophysical understanding of transmembrane signal transduction, particularly in immune cells such as T-cells, B-cells and mast cells. Our research on aspects of membrane shape is directed at understanding how molecules sort in membrane curvature gradients. This curvature sorting likely contributes substantially to intracellular membrane sorting and trafficking. Furthermore we have recently begun to investigate phase coexistence in binary mixtures of amphiphilic di-block copolymers. Finally, we develop methods to pattern cellular signaling ligands, such as antibodies and adhesion molecules, on pattern scales both above and below optical resolution.

Education

• Postdoctoral associate with Prof. Watt Webb at Cornell University (2001 – 2005)

 

• PhD from Max Planck Institute for Polymer Research and Johannes Gutenberg University of Mainz (2001)

 

• Diploma in Chemistry from the University of Clausthal, Germany (1998)

Selected Publications

31) Heinrich, M., Tian A.,Esposito C., Baumgart T. (2010). Dynamic sorting of lipids and proteins by membrane curvature: a moving phase boundary problem. Proceedings of the National Academy of Sciences. In Print.

30) Johnson, S., Stinson, B., Reminik, J., Go, M., Fang, X., & Baumgart, T. (2010). Temperature dependent phase behavior and protein partitioning in giant plasma membrane vesicles. Biochimica et Biophysica Acta - Biomembranes. In Print.

29) Capraro, B. R., Yoon, Y., Cho, W., Baumgart, T. (2010). Curvature sensing by the epsin N-terminal homology (ENTH) domain measured on cylindrical lipid membrane tethers. Journal of the American Chemical Society, 132 (4), 1200-1201.

28) Levental, I., Byfield, F. J., Choudhourie, P., Madara, J., Gai, F., Baumgart, T., & Janmey P. A. (2009). Cholesterol-dependent phase separation in cell-derived giant plasma membrane vesicles. Biochemical Journal, 424 (2), 163-167.

27) Baker, R. G., Hsu, C. J., Lee, D., Jordan, M. S., Maltzman, J. S., Hammer, D. A., Baumgart, T., & Koretzky, G. A. (2009). The adapter protein SLP-76 mediates “outside-in” integrin signaling and function in T cells. Molecular and Cellular Biology, 29 (20), 5578-5589.

26) Christian, D., Tian, A., Ellenbroek, W., Levental, I., Rajagopal, K., Janmey, P., Liu, A., Baumgart, T., & Discher, D. (2009). Spotted vesicles, striped micelles and Janus assemblies induced by ligand binding. Nature Materials, 8, 843-849. DOI

25) Oh, H., Mohler III, E. R., Tian, A., Baumgart, T., & Diamond, S. L. (2009). Membrane cholesterol is a biomechanical regulator of neutrophil adhesion. Arteriosclerosis, Thrombosis, and Vascular Biology, 29, 1290-1297.

24) Tian, A., Capraro, B. R., Esposito, C., & Baumgart, T. (2009). Bending stiffness depends on curvature of ternary lipid mixture tubular membranes. Biophysical Journal, 97 (6), 1636-1646.

23) Das SL, Jenkins JT, Baumgart T. "Neck geometry and shape transitions in vesicles with co-existing fluid phases: Role of Gaussian curvature stiffness versus spontaneous curvature." Europhysics Letters, 2009, 86, 48003-48008.

22) Tian, A. and Baumgart, T. "Sorting of lipids and proteins in membrane curvature gradients." Biophysical Journal, 2009, 96, 2676-2688.

21) Das S., Tian A., Baumgart T., "Mechanical stability of micropipette aspirated giant vesicles with fluid phase coexistence." Journal of Physical Chemistry, B 2008, 112, 11625-11630.

20) Heinrich M.C., Levental I., Gelman H., Janmey P.A., Baumgart T. "Critical exponents for line tension and dipole density difference from lipid monolayer domain boundary fluctuations." Journal of Physical Chemistry, B 2008, 112, 8063-8068.

Office Location

250 Chemistry Bldg.

Phone

215.573.7539

Fax

215.898.6242

Department of Chemistry

231 S. 34 Street, Philadelphia, PA 19104-6323

215.898.8317 voice | 215.573.2112 fax | web@chem.upenn.edu