Phytochromes are biliprotein light sensors that enable photosynthetic organisms to adapt to positive and negative light environments. The recent discovery of phytochromes in nonphotosynthetic bacteria and fungi document that phytochrome ancestors and their ancient signaling partners have evolved into components of signaling systems found in higher eukaryotes. These studies seek to define how tetrapyrrole and light signals are perceived by and propagated within the phytochrome molecule and transduced to downstream target molecules, specifically addressing the hypothesis that phytochromes function as sensors of linear tetrapyrrole (bilins) and light via regulation of their intrinsic protein kinase activities. Ubiquitous to aerobic organisms, bilins appear to play important signaling roles in metazoans, their levels being linked to anoxia, xenobiotic-induced oxidative stress and vascular damage. The mechanism of this ancient signaling pathway is therefore of fundamental importance for understanding and regulating analogous signaling systems in other eukaryotes, including humans. In addition to leading to new approaches to regulate light responsiveness and productivity of plants, our primary food source, another long term consequence of these studies is the development of phytochrome-based approaches for new light-based therapies. The long term goal is to define the structural basis for the regulatory functions of each member of the extended phytochrome family at the molecular level. This understanding will not only enable the design of new approaches for regulation of light-mediated growth and development of agronomically important crop species, but will facilitate development of phytochrome-based technologies for regulation of important biochemical processes (e.g., transcription, protein stability and/or protein localization) within living cells.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM068552-02
Application #
6787687
Study Section
Cell Development and Function Integrated Review Group (CDF)
Program Officer
Ikeda, Richard A
Project Start
2003-08-05
Project End
2007-07-31
Budget Start
2004-08-01
Budget End
2005-07-31
Support Year
2
Fiscal Year
2004
Total Cost
$308,547
Indirect Cost
Name
University of California Davis
Department
Anatomy/Cell Biology
Type
Schools of Arts and Sciences
DUNS #
047120084
City
Davis
State
CA
Country
United States
Zip Code
95618
Kirpich, Julia S; Mix, L Tyler; Martin, Shelley S et al. (2018) Protonation Heterogeneity Modulates the Ultrafast Photocycle Initiation Dynamics of Phytochrome Cph1. J Phys Chem Lett 9:3454-3462
Baloban, Mikhail; Shcherbakova, Daria M; Pletnev, Sergei et al. (2017) Designing brighter near-infrared fluorescent proteins: insights from structural and biochemical studies. Chem Sci 8:4546-4557
Rockwell, Nathan C; Lagarias, J Clark (2017) Phytochrome diversification in cyanobacteria and eukaryotic algae. Curr Opin Plant Biol 37:87-93
Wittkopp, Tyler M; Schmollinger, Stefan; Saroussi, Shai et al. (2017) Bilin-Dependent Photoacclimation in Chlamydomonas reinhardtii. Plant Cell 29:2711-2726
Duanmu, Deqiang; Rockwell, Nathan C; Lagarias, J Clark (2017) Algal light sensing and photoacclimation in aquatic environments. Plant Cell Environ 40:2558-2570
Rockwell, Nathan C; Martin, Shelley S; Li, Fay-Wei et al. (2017) The phycocyanobilin chromophore of streptophyte algal phytochromes is synthesized by HY2. New Phytol 214:1145-1157
Rockwell, Nathan C; Lagarias, J Clark (2017) Ferredoxin-dependent bilin reductases in eukaryotic algae: Ubiquity and diversity. J Plant Physiol 217:57-67
Berlin, Shai; Carroll, Elizabeth C; Newman, Zachary L et al. (2015) Photoactivatable genetically encoded calcium indicators for targeted neuronal imaging. Nat Methods 12:852-8
Jones, Matthew Alan; Hu, Wei; Litthauer, Suzanne et al. (2015) A Constitutively Active Allele of Phytochrome B Maintains Circadian Robustness in the Absence of Light. Plant Physiol 169:814-25
Kim, Peter W; Rockwell, Nathan C; Martin, Shelley S et al. (2014) Heterogeneous photodynamics of the pfr state in the cyanobacterial phytochrome Cph1. Biochemistry 53:4601-11

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