Signal transduction networks are a crucial part of the circuitry by which a cell regulates its growth and developmental program and its response to its environment. Faulty or malfunctioning signaling pathways underlie the molecular pathology of many diseases, particularly cancer. Protein kinase cases are central components of many signaling pathways. Often, the transmission of different upstream signals involves common protein kinases, yet elicits distinct (and appropriate) outcomes. On the other hand, distinct pathways may contain highly similar protein kinase cascades, yet remain appropriately insulated from one another. How specificity form cellular to signal response is maintained in such cases is not well understood, and a fundamental problem in cell biology. This proposal presents experiments that address the role of a high-affinity protein-protein interactions in the specificity of signal transmission between mitogen-activated protein kinases (MAPKs, also called extracellular-signal regulated kinases, or ERKs) and MAPK/ERK kinases (MEKs). Specifically, a short, evolutionarily conserved motif ( the MAPK docking site) has been identified on MEKs that, in yeast, has been shown to mediate high-affinity binding to the cognate MAPKs.
Specific aims are to determine if the docking sites of human MEK1 and Mek2 bind to the cognate human MAPKs, to characterize the amino acid residues on the yeast and human MEKs and MAPKs that mediate this high-affinity binding, and to use this information to construct appropriate mutants to learn more about the in vivo functions of MEK/MAPK docking. In so doing, we will address two (non-exclusive) hypotheses about the role of high-affinity protein-kinase substrate interactions in protein kinase signaling the transmission hypothesis and the specificity hypothesis. Inappropriate MAPK activation, such as that evoked by the well known oncoproteins Ras and Raf, is sufficient for the neoplastic transformation of cultured mammalian cells and consequent tumorigenesis. The research proposed herein should improve our understanding of the signal transmission and signal specificity in MAPK cascades. More generally, this research could lead to better understanding of how protein kinases find their targets, improve our ability to predict targets, and may ultimately suggest novel approaches to therapy based upon the modulation of protein kinase interactions.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM060366-04
Application #
6628839
Study Section
Cell Development and Function Integrated Review Group (CDF)
Program Officer
Anderson, Richard A
Project Start
2000-02-01
Project End
2005-01-31
Budget Start
2003-02-01
Budget End
2004-01-31
Support Year
4
Fiscal Year
2003
Total Cost
$236,230
Indirect Cost
Name
University of California Irvine
Department
Anatomy/Cell Biology
Type
Schools of Arts and Sciences
DUNS #
046705849
City
Irvine
State
CA
Country
United States
Zip Code
92697
Bardwell, A Jane; Bardwell, Lee (2015) Two hydrophobic residues can determine the specificity of mitogen-activated protein kinase docking interactions. J Biol Chem 290:26661-74
Liu, Xinfeng; Bardwell, Lee; Nie, Qing (2010) A combination of multisite phosphorylation and substrate sequestration produces switchlike responses. Biophys J 98:1396-407
Whisenant, Thomas C; Ho, David T; Benz, Ryan W et al. (2010) Computational prediction and experimental verification of new MAP kinase docking sites and substrates including Gli transcription factors. PLoS Comput Biol 6:
Compani, Behnam; Su, Trent; Chang, Ivan et al. (2010) A scalable and integrative system for pathway bioinformatics and systems biology. Adv Exp Med Biol 680:523-34
Haney, Seth; Bardwell, Lee; Nie, Qing (2010) Ultrasensitive responses and specificity in cell signaling. BMC Syst Biol 4:119
Bardwell, A Jane; Frankson, Erlynn; Bardwell, Lee (2009) Selectivity of docking sites in MAPK kinases. J Biol Chem 284:13165-73
Hilioti, Zoe; Sabbagh Jr, Walid; Paliwal, Saurabh et al. (2008) Oscillatory phosphorylation of yeast Fus3 MAP kinase controls periodic gene expression and morphogenesis. Curr Biol 18:1700-6
Bardwell, Lee (2008) Signal transduction: turning a switch into a rheostat. Curr Biol 18:R910-2
Bardwell, Lee; Zou, Xiufen; Nie, Qing et al. (2007) Mathematical models of specificity in cell signaling. Biophys J 92:3425-41
Bardwell, Lee; Shah, Kandarp (2006) Analysis of mitogen-activated protein kinase activation and interactions with regulators and substrates. Methods 40:213-23

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