Office: Barus & Holley 702
Lab: Barus & Holley 409
Phone (Office): 401-863-2292
Phone (Lab): 401-863-1405
Email: Jay_Tang@brown.edu

• BS in physics from Peking University, July, 1987
• Ph.D. in physics from Brandeis University, February, 1995
• Postdoctoral fellow, Harvard Medical School, July 1994-September 1997
• Instructor of Medicine, Harvard Medical School, October 1997-August 1999
• Assistant Professor of Physics, Indiana University, August 1999-July 2002
• Assistant Professor of Physics and Engineering, Brown University, July 2002-

We are currently involved in a new research program of molecular biophysics. The main goal of this research effort is to understand the mechanisms and properties of protein assemblies. In particular, the lab studies the assembly of the so-called cytoskeletal proteins, such as the proteins actin and tubulin, which form functional filaments in cells.

Filamentous assemblies of proteins and nucleotides form a class of biomaterials with physical properties distinct from those of most synthetic polymers. Among these biomaterials are cytoskeletal filaments including filamentous actin (F-actin), microtubules, and intermediate filaments; collagen fibers in the extra-cellular matrix; duplex DNA in both extended and condensed forms; and filamentous viruses such as the bacteriophages fd, M13, and pf1. Various states of assembly occur in solutions of this class of biopolymers, including isotropic networks, liquid crystalline phases, and densely packed lateral aggregates often described as paracrystalline bundles. Elucidating the molecular interactions that govern the formation of all these states will provide a means to predict and manipulate transitions among them, and will therefore have potential applications for material science and biomedical engineering.

The long-term goal of this line of research is to explore special features of these polymer systems in connection with phase transitions, and to identify and assess the inter-molecular forces that govern various states of assembly in aqueous solutions. We also explore strategies for potential treatment of certain human diseases based on the properties of large protein assemblies.

Additionally, the the laboratory has recently undertaken biophysical studies of bacterial adhesion and motility, using the aquatic bacterial species Caulobacter crescentus. The study has revealed an extraordinary strength of adhesion, which has implications for potentially developing a new class of adhesives. An ongoing study of the Caulobacter swarmer cells suggests a much higher swiming efficiency than E. coli and V. alginolyticus, showing an interersting example of adaptation of microorganisms through the course of evolution.

Tang, J. and Janmey, P.
The Polyelectrolyte Nature of F-actin and the Mechanism of Actin Bundle Formation.
J. of Biol. Chem. 271 8556-8563 (1996)

Tang, J. X., Ito, T., Tao, T., Traub, P., and Janmey, P.
Opposite Effects of Electrostatics and Steric Exclusion on Bundle Formation by F-actin and Other Filamentous Polyelectrolytes.
Biochemistry 36, 12600-12607 (1997)

Tang, J. X. , Janmey, P., Stossel, T., and Ito, T.,
Thiol Oxidation of Actin Produces Dimers That Enhance the Elasticity of the F-actin Network.
Biophys. J. 76, 2208-2215 (1999)

Wong, G. C. L., Tang, J. X., Lin, A., Li, Y., Janmey, P., and Safinya, C. R.,
Hierarchical Self-assembly of F-actin and Cationic Lipid Complexes: Stacked Three-layer Tubule Networks.
Science 288, 2035-2039 (2000)

Schmidt, F. G., Hinner, B., Sackmann, E., and Tang, J. X.,
Viscoelastic Properties of Semiflexible Filamentous Bacteriophage fd,
Phys. Rev. E 62, 5509-5517 (2000)

Tang, J. X., Janmey, P., Lyubartsev, A., and Nordenskiöld, L.,
Metal Ion Induced Lateral Aggregation of Filamentous Viruses fd and M13.
Biophys. J 83, 566-581 (2002)

Full Publication List