Cellular behavior is modulated by environmental signals including nutrients, osmotic stress, hormones and neurotransmitters. These signals can vary considerably in dose, duration, and directionality. This proposal seeks to (i) quantitatively measure the yeast pheromone response pathway, both in time and space, (ii) devise computational models that describe the observed behaviors, and (iii) test the validity of each model through further experimentation. The over-arching hypothesis is that mathematical techniques developed for studying dynamical systems can explain how pathway components interpret and translate spatial cues outside the cell to evoke appropriate responses inside the cell. The focus will be on proteins that modulate the time-dependent behaviors of the pheromone pathway in yeast, and in particular how these modulators contribute to proper signal transduction. Models will be tested experimentally at the molecular and cellular level, and include the use of an innovative gradient flow chamber. There are three specific aims, focused on three different proteins acting at three distinct steps in the pathway. All three proteins are required for gradient-sensing activity.
Aim 1 will investigate time-dependent regulation by the scaffold protein Ste5.
This aim will test the hypothesis that Ste5 modulates signaling by imposing a delay between each of two phosphorylation events needed for full activation of a MAP kinase Fus3.
Aim 2 will investigate time- and space-dependent regulation by the RGS protein Sst2.
This aim will test the hypothesis that Sst2 functions as a scaffold protein that coordinates G protein activation (by the receptor) and inactivation (of the G protein), and thereby orients the cell towards a gradient stimulus.
Aim 3 will investigate time- and space-dependent regulation by the pheromone protease Bar1.
This aim will test the hypothesis that Bar1 remodels the gradient, and thereby coordinates the behavior of two cells responding to the same stimulus.

Public Health Relevance

Proper cell function requires the ability to detect and respond appropriately to hormones, neurotransmitters and drugs. The cellular machinery responsible for signal transmission is conserved from humans to yeast. This project uses multi-disciplinary approaches, including biological experiments, microfabricated growth chambers and computer simulations, to establish how the direction and strength of a stimulus are interpreted by the cell. The broader objective is to understand the role of spatial and temporal information in cell signaling, and eventually predict what drug treatments will be most effective in combating human diseases.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM073180-08
Application #
8253708
Study Section
Modeling and Analysis of Biological Systems Study Section (MABS)
Program Officer
Dunsmore, Sarah
Project Start
2005-04-01
Project End
2013-04-30
Budget Start
2012-05-01
Budget End
2013-04-30
Support Year
8
Fiscal Year
2012
Total Cost
$335,169
Indirect Cost
$105,365
Name
University of North Carolina Chapel Hill
Department
Biochemistry
Type
Schools of Medicine
DUNS #
608195277
City
Chapel Hill
State
NC
Country
United States
Zip Code
27599
Baker, Rachael; Lewis, Steven M; Sasaki, Atsuo T et al. (2013) Site-specific monoubiquitination activates Ras by impeding GTPase-activating protein function. Nat Struct Mol Biol 20:46-52
Isom, Daniel G; Sridharan, Vishwajith; Baker, Rachael et al. (2013) Protons as second messenger regulators of G protein signaling. Mol Cell 51:531-8
Jones, Janice C; Jones, Alan M; Temple, Brenda R S et al. (2012) Differences in intradomain and interdomain motion confer distinct activation properties to structurally similar Gýý proteins. Proc Natl Acad Sci U S A 109:7275-9
Nagiec, Michal J; Dohlman, Henrik G (2012) Checkpoints in a yeast differentiation pathway coordinate signaling during hyperosmotic stress. PLoS Genet 8:e1002437
Zhu, Ming; Torres, Matthew P; Kelley, Joshua B et al. (2011) Pheromone- and RSP5-dependent ubiquitination of the G protein beta subunit Ste4 in yeast. J Biol Chem 286:27147-55
Jin, Meng; Errede, Beverly; Behar, Marcelo et al. (2011) Yeast dynamically modify their environment to achieve better mating efficiency. Sci Signal 4:ra54
Kapustina, Maryna; Weinreb, Gabriel E; Costigliola, Nancy et al. (2008) Mechanical and biochemical modeling of cortical oscillations in spreading cells. Biophys J 94:4605-20
Hao, Nan; Nayak, Sujata; Behar, Marcelo et al. (2008) Regulation of cell signaling dynamics by the protein kinase-scaffold Ste5. Mol Cell 30:649-56
Behar, Marcelo; Hao, Nan; Dohlman, Henrik G et al. (2008) Dose-to-duration encoding and signaling beyond saturation in intracellular signaling networks. PLoS Comput Biol 4:e1000197
Behar, Marcelo; Dohlman, Henrik G; Elston, Timothy C (2007) Kinetic insulation as an effective mechanism for achieving pathway specificity in intracellular signaling networks. Proc Natl Acad Sci U S A 104:16146-51

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