Most signaling pathways involve labile, dynamic protein complexes that rapidly dissociate and that are therefore notoriously difficult to analyze by high resolution structural studies. In this proposal we will use protein engineering to determine the crystal structure of a dynamic signaling complex of the crucial plant stress hormone abscisic acid (ABA). ABA is an ancient signaling molecule that is found in plants, fungi, and metazoans ranging from sponges to humans. In plants, ABA is an essential hormone and the central regulator to protect plants against abiotic stresses such as drought, cold, and salinity. These stresses are major limiting factors in crop production and therefore main contributors to malnutrition due to food shortage. This is relevant to human health because malnutrition contributes to more than 50% of human disease worldwide, including cancer and infectious diseases. Understanding the detailed mechanism of ABA signaling will be critical to provide a mechanistic basis for genetic engineering of ABA pathways in plants. At the center of ABA signaling are a family of AMPK-related protein kinases that relay the ABA signal by phosphorylating transcription factors, ion channels, and second-messenger-generating enzymes. These kinases are under the control of type 2C protein phosphatases (PP2Cs) and intracellular ABA receptors. In this proposal evidence is presented for the existence of quaternary signaling complexes that contain the receptors, ABA, PP2Cs, and SnRK2s. We will use protein engineering to stabilize these complexes and make them amenable to X-ray crystallography. The structure of these complexes will provide important insight into the function of these complexes and will identify the key interacting residues for all protein-protein and protein-ABA interactions in the context of the complex. We will mutate these residues to determine the function of these interactions in biochemical and cell-based assays as well as in vivo in transgenic plants. The outcome of this project will provide a comprehensive framework for structural understanding of receptor, ABA, PP2C, and SnRK2 interactions in ABA signaling and will thus provide a mechanistic basis for modulating ABA pathways in plants to improve their water use efficiency and food production.

Public Health Relevance

Malnutrition due to food shortage alone contributes to more than 50% of human disease worldwide, including cancer and infectious diseases. The major limitation for food production is the scarceness of fresh water resources at the global scale where >70% of fresh water is currently used by agriculture. One solution to this critical problem is to increase the water use efficiency of crop plants, but a critical barrier toward this solutionis our poor understanding of molecular mechanisms underlying plant responses to water stress;this project begins to address this critical problem by studying the signaling mechanism of abscisic acid (ABA), which is the central regulator in plants to cope with water stress.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM102545-02
Application #
8500400
Study Section
Macromolecular Structure and Function E Study Section (MSFE)
Program Officer
Flicker, Paula F
Project Start
2012-07-01
Project End
2015-06-30
Budget Start
2013-07-01
Budget End
2014-06-30
Support Year
2
Fiscal Year
2013
Total Cost
$348,365
Indirect Cost
$165,015
Name
Van Andel Research Institute
Department
Type
DUNS #
129273160
City
Grand Rapids
State
MI
Country
United States
Zip Code
49503
Zhao, Li-Hua; Yin, Yanting; Yang, Dehua et al. (2016) Differential Requirement of the Extracellular Domain in Activation of Class B G Protein-coupled Receptors. J Biol Chem 291:15119-30
Rowe, Timothy B; Luo, Zhe-Xi; Ketcham, Richard A et al. (2016) X-ray computed tomography datasets for forensic analysis of vertebrate fossils. Sci Data 3:160040
Golani, Lalit K; Wallace-Povirk, Adrianne; Deis, Siobhan M et al. (2016) Tumor Targeting with Novel 6-Substituted Pyrrolo [2,3-d] Pyrimidine Antifolates with Heteroatom Bridge Substitutions via Cellular Uptake by Folate Receptor α and the Proton-Coupled Folate Transporter and Inhibition of de Novo Purine Nucleotide Biosynthes J Med Chem 59:7856-76
Xu, Ting-Hai; Yan, Yan; Kang, Yanyong et al. (2016) Alzheimer's disease-associated mutations increase amyloid precursor protein resistance to γ-secretase cleavage and the Aβ42/Aβ40 ratio. Cell Discov 2:16026
Zhou, X Edward; Gao, Xiang; Barty, Anton et al. (2016) X-ray laser diffraction for structure determination of the rhodopsin-arrestin complex. Sci Data 3:160021
Zhang, Feng; Yao, Jian; Ke, Jiyuan et al. (2015) Structural basis of JAZ repression of MYC transcription factors in jasmonate signalling. Nature 525:269-73
Zhi, Xiaoyong; Zhou, X Edward; He, Yuanzheng et al. (2015) Structural basis for corepressor assembly by the orphan nuclear receptor TLX. Genes Dev 29:440-50
Kang, Yanyong; Zhou, X Edward; Gao, Xiang et al. (2015) Crystal structure of rhodopsin bound to arrestin by femtosecond X-ray laser. Nature 523:561-7
Ke, Jiyuan; Ma, Honglei; Gu, Xin et al. (2015) Structural basis for recognition of diverse transcriptional repressors by the TOPLESS family of corepressors. Sci Adv 1:e1500107
Shen, Guobo; Ke, Jiyuan; Wang, Zhizhi et al. (2015) Structural basis of the Norrin-Frizzled 4 interaction. Cell Res 25:1078-81

Showing the most recent 10 out of 19 publications