Mark D Goulian, Ph D

faculty photo
Edward and Louise W. Kahn Term Professor of Biology and Physics
Department: Biology

Contact information
204F, Lynch Biology Laboratory
433 South University Ave
Philadelphia, PA 19104-6018
Office: 215 573-6991
Fax: 215 898-8780
A.B. (Physics)
Harvard University, 1985.
Ph.D. (Physics)
Harvard University, 1990.
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Description of Research Expertise

Research Interests
Bacterial regulatory circuits and signal transduction

Key words: two-component signaling, signaling networks, mathematical modeling, directed evolution, fluorescence microscopy.

Description of Research
Research in the Goulian lab is focused on the regulatory circuits that bacteria use to sense and respond to the environment. At present, most of the efforts in the lab explore aspects of two-component signaling in E. coli. Two-component systems make up a large family of regulatory circuits that mediate responses to diverse environmental signals and play a central role in bacterial physiology. In their simplest form, these circuits are composed of two proteins, a sensor kinase and a response regulator. The response regulator is usually a transcription factor, although in some instances it controls other cellular processes such as protein degradation, protein localization, or flagellar motor switching. Depending on the circuit, additional phospho-transfer steps or additional regulatory proteins may be involved in the signal transduction process. Two-component systems provide an excellent context in which to study cell signaling and biochemical circuits. They tend to be relatively simple, with a small number of components; they can be found in genetically tractable, well-studied organisms; and there are many examples of such systems that can be used for comparing and contrasting designs. (E. coli K-12 contains roughly 30 two-component systems). Current research applies techniques from genetics, bacterial physiology, fluorescence microscopy, and mathematical modeling to explore the design principles underlying two-component systems and to identify the mechanisms that maintain fidelity in processing signals. New techniques to measure signaling activity, both across populations and at the level of single cells, are being developed in order to formulate and test quantitative models. In addition, synthetic networks are being engineered by rational design and directed evolution in order to build novel circuits and to explore the general design constraints for cell signaling.
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Last updated: 12/05/2012
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