A fundamental biological question is how external stimuli evoke cellular responses. One prevalent type of environmental sensor in prokaryotic organisms is the two-component system (TCS). A canonical TCS consists of a membrane-spanning sensor histidine kinase (SHK) and a cytoplasmic response regulator (RR). A recent survey of 145 prokaryotic genomes detected more than 4000 TCSs. TCSs regulate a diverse array of virulence factors. Identifying two-component signaling pathways that lead to enhanced pathogenicity is essential to understanding complex host-pathogen interactions. The specific hypothesis examined is that SHK-membrane interactions can be identified and harnessed to modulate SHK signal output in a predictable manner. Specifically targeting individual SHK signal output could be used to rapidly unravel two-component signal pathways in any pathogenic organism of interest.
Three specific aims are designed to develop this methodology.
Specific Aim 1 will identify and harness interactions between TM2 of two well-characterized SHKs, EnvZ and NarX, and the cellular membrane using fluorescent and enzymatic reporters.
Specific Aim 2 will determine the role of protein-membrane interactions during signal transduction by the HAMP domains of EnvZ and NarX. These interactions will be examined through use of random mutagenesis and fluorescent microscopy.
Specific Aim 3 will couple transcriptional profiling with harnessed SHK-membrane interactions (from Specific Aims 1 and 2) to establish a methodology for rapidly unraveling two-component signaling pathways in any pathogenic organism of interest. The long-term goal of this research is to create a method for rapidly identifying the signaling pathways that regulate the virulence of pathogenic microorganisms. This research will lead to a better understanding of complex host-pathogen interactions and will result in the detection of previously unidentified therapeutic targets.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Postdoctoral Individual National Research Service Award (F32)
Project #
5F32AI075773-02
Application #
7695549
Study Section
Special Emphasis Panel (ZRG1-F13-P (20))
Program Officer
Korpela, Jukka K
Project Start
2008-09-30
Project End
2010-06-30
Budget Start
2009-09-30
Budget End
2010-06-30
Support Year
2
Fiscal Year
2009
Total Cost
$29,520
Indirect Cost
Name
Stockholm University
Department
Type
DUNS #
350582276
City
Stockholm
State
Country
Sweden
Zip Code
S-106-91
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Adase, Christopher A; Draheim, Roger R; Rueda, Garrett et al. (2013) Residues at the cytoplasmic end of transmembrane helix 2 determine the signal output of the TarEc chemoreceptor. Biochemistry 52:2729-38
Adase, Christopher A; Draheim, Roger R; Manson, Michael D (2012) The residue composition of the aromatic anchor of the second transmembrane helix determines the signaling properties of the aspartate/maltose chemoreceptor Tar of Escherichia coli. Biochemistry 51:1925-32
Unnerståle, Sofia; Mäler, Lena; Draheim, Roger R (2011) Structural characterization of AS1-membrane interactions from a subset of HAMP domains. Biochim Biophys Acta 1808:2403-12
Wright, Gus A; Crowder, Rachel L; Draheim, Roger R et al. (2011) Mutational analysis of the transmembrane helix 2-HAMP domain connection in the Escherichia coli aspartate chemoreceptor tar. J Bacteriol 193:82-90