The long-term goal of the proposed research is to describe the signal transduction pathway that leads to bacterial chemotaxis in chemical terms. The bacterial chemotaxis signaling system has emerged as an archetype for transmembrane signaling and molecular information processing. Investigations of this system have revealed that signals are transmitted through a macromolecular assembly of the chemoreceptors and their associated signaling proteins. A forefront research objective is to understand the molecular mechanisms that underlie the ability of this higher order protein assembly to transmit signals. The three Specific Aims of this application follow.
Aim 1 is to use synthetic ligands, protein engineering, and nanoparticles in conjunction with electron cryotomography to determine the organization of the signaling array and how chemoeffectors influence it.
Aim 2 is to implement chemical biology strategies compatible with native membrane preparations to elucidate protein-protein interaction surfaces in the reconstituted signaling lattice.
Aim 3 is to probe the relationship between the microbial responses of chemotaxis and swarming using tools developed in Aims 1 and 2. In pursuing these Aims, we shall employ methods and ideas from organic chemistry, microbiology, protein engineering, polymer and materials chemistry, structural biology, and chemical biology. We anticipate that this research will provide insight into the molecular mechanisms that underlie chemotactic signaling and swarming in bacteria as well as new tools and strategies to explore signal transduction pathways in general.

Public Health Relevance

The ability of cells to detect and respond to molecular signals is essential for their survival. Tremendous strides have been made in identifying and characterizing the function of cellular components that transmit signals in cells, but a chemical level understanding of even one pathway is lacking. The proposed research will bring together a diverse set of approaches to determine how complexes of proteins function to cause bacteria to run toward attractants or away from repellents.

National Institute of Health (NIH)
National Institute of General Medical Sciences (NIGMS)
Research Project (R01)
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Special Emphasis Panel (ZRG1-SBCA-A (02))
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Marino, Pamela
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University of Wisconsin Madison
Schools of Arts and Sciences
United States
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Briegel, Ariane; Wong, Margaret L; Hodges, Heather L et al. (2014) New insights into bacterial chemoreceptor array structure and assembly from electron cryotomography. Biochemistry 53:1575-85
Kiessling, Laura L; Grim, Joseph C (2013) Glycopolymer probes of signal transduction. Chem Soc Rev 42:4476-91
Wong, Margaret L; Guzei, Ilia A; Kiessling, Laura L (2012) An asymmetric synthesis of L-pyrrolysine. Org Lett 14:1378-81
Underbakke, Eric S; Zhu, Yimin; Kiessling, Laura L (2011) Protein footprinting in a complex milieu: identifying the interaction surfaces of the chemotaxis adaptor protein CheW. J Mol Biol 409:483-95
Jiarpinitnun, Chutima; Kiessling, Laura L (2010) Unexpected enhancement in biological activity of a GPCR ligand induced by an oligoethylene glycol substituent. J Am Chem Soc 132:8844-5
Underbakke, Eric S; Kiessling, Laura L (2010) Classifying chemoreceptors: quantity versus quality. EMBO J 29:3435-6
Kiessling, Laura L; Splain, Rebecca A (2010) Chemical approaches to glycobiology. Annu Rev Biochem 79:619-53
Lamanna, Allison C; Kiessling, Laura L (2009) Flow cytometry reveals that multivalent chemoattractants effect swarmer cell dedifferentiation. ACS Chem Biol 4:828-33
Borrok, M Jack; Zhu, Yimin; Forest, Katrina T et al. (2009) Structure-based design of a periplasmic binding protein antagonist that prevents domain closure. ACS Chem Biol 4:447-56
Underbakke, Eric S; Zhu, Yimin; Kiessling, Laura L (2008) Isotope-coded affinity tags with tunable reactivities for protein footprinting. Angew Chem Int Ed Engl 47:9677-80

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