Abstract

G-proteins serve as molecular switches responding to a variety of extracellular cues to relay intracellularresponses. Dysregulated G-protein signaling leads to pathophysiologies in numerous organ systems. The currentproject will utilize phage display peptides that bind to specific nucleotide-bound states of G-alpha subunits in acombined approach of structural biology, biochemistry, and live cell imaging to more clearly elucidate thespatiotemporal dynamics of G-protein signaling pathways.
Aim 1 : To delineate the structural determinants of nucleotide-selective binding of phage peptides to cognate G-alphasubunits using x-ray crystallographyAim 2: To determine the effects of phage peptides on the nucleotide cycle of G-protein subunits as potential directmodulators of G-protein regulation using in vitro biochemical approachesAim 3: To determine the spatiotemporal dynamics of G-protein activation using phage peptides as in vivo biosensorsthat incorporate environmentally-sensitive, solvatochromatic dyes with live cell imaging techniques

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Postdoctoral Individual National Research Service Award (F32)
Project #
5F32GM076944-02
Application #
7167450
Study Section
Special Emphasis Panel (ZRG1-F05 (20))
Program Officer
Fabian, Miles
Project Start
2006-01-01
Project End
2007-12-01
Budget Start
2007-01-01
Budget End
2007-12-01
Support Year
2
Fiscal Year
2007
Total Cost
$46,925
Indirect Cost

  Institution

Name
University of North Carolina Chapel Hill
Department
Pharmacology
Type
Schools of Medicine
DUNS #
608195277
City
Chapel Hill
State
NC
Country
United States
Zip Code
27599

  Publications

(2011) Retraction notice to: Structure of the parathyroid hormone receptor C terminus bound to the G-protein dimer G?1?2. Structure 19:1200
Johnston, Christopher A; Afshar, Katayoun; Snyder, Jason T et al. (2008) Structural determinants underlying the temperature-sensitive nature of a Galpha mutant in asymmetric cell division of Caenorhabditis elegans. J Biol Chem 283:21550-8
Johnston, Christopher A; Kimple, Adam J; Giguere, Patrick M et al. (2008) Structure of the parathyroid hormone receptor C terminus bound to the G-protein dimer Gbeta1gamma2. Structure 16:1086-94
Johnston, Christopher A; Willard, Francis S; Ramer, J Kevin et al. (2008) State-selective binding peptides for heterotrimeric G-protein subunits: novel tools for investigating G-protein signaling dynamics. Comb Chem High Throughput Screen 11:370-81
Johnston, Christopher A; Siderovski, David P (2007) Structural basis for nucleotide exchange on G alpha i subunits and receptor coupling specificity. Proc Natl Acad Sci U S A 104:2001-6
Johnston, Christopher A; Taylor, J Philip; Gao, Yajun et al. (2007) GTPase acceleration as the rate-limiting step in Arabidopsis G protein-coupled sugar signaling. Proc Natl Acad Sci U S A 104:17317-22
Johnston, Christopher A; Siderovski, David P (2007) Receptor-mediated activation of heterotrimeric G-proteins: current structural insights. Mol Pharmacol 72:219-30
Johnston, Christopher A; Lobanova, Ekaterina S; Shavkunov, Alexander S et al. (2006) Minimal determinants for binding activated G alpha from the structure of a G alpha(i1)-peptide dimer. Biochemistry 45:11390-400