This continuing project investigates the broad class of two-component signaling pathways widespread in eukaryotes and ubiquitous in prokaryotes. Two-component pathways play especially critical roles in bacteria, where they control most normal cellular processes and most pathological processes including wound detection during infection, activation of virulence, and antibiotic resistance. The receptors and signaling proteins which comprise these ancient pathways are conserved across species and are attractive targets for broad-spectrum antibiotics. Thus, a basic mechanistic understanding of the pathway components will have significant impacts on signaling biology and pharmaceutical development. The present project focuses on the best characterized two-component signaling pathway: the chemosensory pathway of bacterial chemotaxis. The soluble components of this pathway assemble onto the transmembrane receptor to yield a large, membrane-bound sensory complex. The sensory complex is well-suited for molecular analysis, but much remains to be learned about its structure and its mechanism of signal transduction. The Progress Report describes new insights into fundamental features of the complex, including (i) the mechanism of receptor transmembrane signaling, (ii) the mechanism of receptor adaptation, (iii) the mechanism of signal transduction through the receptor cytoplasmic domain, and (iv) the architecture of the sensory complex. The four Specific Aims of continuing studies address two broad questions. First, how are transmembrane and adaptation signals transmitted through the receptor to the kinase? Second, how do receptor signals control the on-off switching of the kinase? Novel approaches utilizing site-directed cysteine chemistry and spectroscopy are being used to answer these questions in the fully functional, membrane- bound sensory complex. Overall, the broad goal of these studies is to understand the mechanisms of receptor transmembrane signaling, receptor adaptation, and kinase regulation in the native environment that includes the membrane and other pathway components. ? ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM040731-19
Application #
7191566
Study Section
Special Emphasis Panel (ZRG1-BCMB-B (02))
Program Officer
Flicker, Paula F
Project Start
1988-07-01
Project End
2010-02-28
Budget Start
2007-03-01
Budget End
2008-02-29
Support Year
19
Fiscal Year
2007
Total Cost
$250,429
Indirect Cost
Name
University of Colorado at Boulder
Department
Chemistry
Type
Schools of Arts and Sciences
DUNS #
007431505
City
Boulder
State
CO
Country
United States
Zip Code
80309
Parkinson, John S; Hazelbauer, Gerald L; Falke, Joseph J (2015) Signaling and sensory adaptation in Escherichia coli chemoreceptors: 2015 update. Trends Microbiol 23:257-66
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
Briegel, Ariane; Wong, Margaret L; Hodges, Heather L et al. (2014) Correction to new insights into bacterial chemoreceptor array structure and assembly from electron cryotomography. Biochemistry 53:6624
Falke, Joseph J; Piasta, Kene N (2014) Architecture and signal transduction mechanism of the bacterial chemosensory array: progress, controversies, and challenges. Curr Opin Struct Biol 29:85-94
Piasta, Kene N; Falke, Joseph J (2014) Increasing and decreasing the ultrastability of bacterial chemotaxis core signaling complexes by modifying protein-protein contacts. Biochemistry 53:5592-600
Falke, Joseph J (2014) Piston versus scissors: chemotaxis receptors versus sensor His-kinase receptors in two-component signaling pathways. Structure 22:1219-1220
Piasta, Kene N; Ulliman, Caleb J; Slivka, Peter F et al. (2013) Defining a key receptor-CheA kinase contact and elucidating its function in the membrane-bound bacterial chemosensory array: a disulfide mapping and TAM-IDS Study. Biochemistry 52:3866-80
Li, Xiaoxiao; Fleetwood, Aaron D; Bayas, Camille et al. (2013) The 3.2 Å resolution structure of a receptor: CheA:CheW signaling complex defines overlapping binding sites and key residue interactions within bacterial chemosensory arrays. Biochemistry 52:3852-65
Natale, Andrew M; Duplantis, Jane L; Piasta, Kene N et al. (2013) Structure, function, and on-off switching of a core unit contact between CheA kinase and CheW adaptor protein in the bacterial chemosensory array: A disulfide mapping and mutagenesis study. Biochemistry 52:7753-65
Slivka, Peter F; Falke, Joseph J (2012) Isolated bacterial chemosensory array possesses quasi- and ultrastable components: functional links between array stability, cooperativity, and order. Biochemistry 51:10218-28

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