Transmembrane signaling is a process common to all living cells. The program of work described this application is designed to discover how extended interactions between receptor subunits are important for transmembrane signaling in the chemosensory pathway of Escherichia coli. Since these interactions appear to be an essential part of the signaling process, a deeper understanding of them may lead to insights of fundamental importance to the mechanism of trans-bilayer communication in all cells. The available evidence suggests that the trans-bilayer communication can, under some circumstances, mutually stabilize the ligand binding interaction on both sides of the membrane, and in other situations the communication is predicted to be mutually destabilizing. This concept will be put to the test with measurements of ligand binding and protein-protein interaction between the receptor, and its various ligands. The experiments are designed to test the influence of one ligand on the binding of others. In addition to an equilibrium investigation of the system, the dynamics of subunit assembly and disassembly will be more thoroughly studied, since recent results indicate that the assembly/disassembly process is a ligand-catalyzed process, and can occur on a time scale relevant for signaling. These data will be used to distinguish two models of transmembrane signaling, one in which the chemoreceptors and the associated signaling proteins are in a stably-assembled complex, and another in which the receptor complexes dynamically associate and dissociate on the signaling time scale.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
2R01GM053210-04
Application #
6292563
Study Section
Molecular and Cellular Biophysics Study Section (BBCA)
Program Officer
Shapiro, Bert I
Project Start
2001-03-01
Project End
2002-02-28
Budget Start
2001-03-01
Budget End
2002-02-28
Support Year
4
Fiscal Year
2001
Total Cost
$173,469
Indirect Cost
Name
University of Massachusetts Amherst
Department
Chemistry
Type
Schools of Arts and Sciences
DUNS #
153223151
City
Amherst
State
MA
Country
United States
Zip Code
01003
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Li, G; Weis, R M (2000) Covalent modification regulates ligand binding to receptor complexes in the chemosensory system of Escherichia coli. Cell 100:357-65

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