plant genetics; transcription factors; protein dynamics; signal transduction; NMR spectroscopy; phosphate homeostasis; X-ray protein crystallography; G-protein signalling; yeast genetics; inositol pyrophosphates; organic chemistry
Ried Martina K., Wild Rebekka, Zhu Jinsheng, Pipercevic Joka, Sturm Kristina, Broger Larissa, Harmel Robert K., Abriata Luciano A., Hothorn Ludwig A., Fiedler Dorothea, Hiller Sebastian, Hothorn Michael (2021), Inositol pyrophosphates promote the interaction of SPX domains with the coiled-coil motif of PHR transcription factors to regulate plant phosphate homeostasis, in Nature Communications
, 12(1), 384-384.
Furkert David, Nadler-Holly Michal, Fiedler Dorothea (2021), Affinity enrichment and identification of inositol poly- and pyrophosphate interactomes, in STAR Protocols
, 2(1), 100277-100277.
Zong Guangning, Jork Nikolaus, Hostachy Sarah, Fiedler Dorothea, Jessen Henning J., Shears Stephen B., Wang Huanchen (2021), New structural insights reveal an expanded reaction cycle for inositol pyrophosphate hydrolysis by human DIPP1, in The FASEB Journal
, 35(2), 1-10.
Hostachy Sarah, Utesch Tillmann, Franke Katy, Dornan Gillian Leigh, Furkert David, Türkaydin Berke, Haucke Volker, Sun Han, Fiedler Dorothea (2021), Dissecting the activation of insulin degrading enzyme by inositol pyrophosphates and their bisphosphonate analogs, in Chemical Science
Chin Alfred C., Gao Zhe, Riley Andrew M., Furkert David, Wittwer Christopher, Dutta Amit, Rojas Tomas, Semenza Evan R., Felder Robin A., Pluznick Jennifer L., Jessen Henning J., Fiedler Dorothea, Potter Barry V. L., Snyder Solomon H., Fu Chenglai (2020), The inositol pyrophosphate 5-InsP 7 drives sodium-potassium pump degradation by relieving an autoinhibitory domain of PI3K p85α, in Science Advances
, 6(44), eabb8542-eabb8542.
Desmarini Desmarini, Lev Sophie, Furkert David, Crossett Ben, Saiardi Adolfo, Kaufman-Francis Keren, Li Cecilia, Sorrell Tania C., Wilkinson-White Lorna, Matthews Jacqueline, Fiedler Dorothea, Djordjevic Julianne Teresa (2020), IP 7 -SPX Domain Interaction Controls Fungal Virulence by Stabilizing Phosphate Signaling Machinery, in mBio
, 11(5), 1-10.
Sahu Soumyadip, Wang Zhenzhen, Jiao Xinfu, Gu Chunfang, Jork Nikolaus, Wittwer Christopher, Li Xingyao, Hostachy Sarah, Fiedler Dorothea, Wang Huanchen, Jessen Henning J., Kiledjian Megerditch, Shears Stephen B. (2020), InsP 7 is a small-molecule regulator of NUDT3-mediated mRNA decapping and processing-body dynamics, in Proceedings of the National Academy of Sciences
, 117(32), 19245-19253.
Furkert David, Hostachy Sarah, Nadler-Holly Michal, Fiedler Dorothea (2020), Triplexed Affinity Reagents to Sample the Mammalian Inositol Pyrophosphate Interactome, in Cell Chemical Biology
, 27(8), 1097-1108.e4.
Li Xingyao, Gu Chunfang, Hostachy Sarah, Sahu Soumyadip, Wittwer Christopher, Jessen Henning J., Fiedler Dorothea, Wang Huanchen, Shears Stephen B. (2020), Control of XPR1-dependent cellular phosphate efflux by InsP 8 is an exemplar for functionally-exclusive inositol pyrophosphate signaling, in Proceedings of the National Academy of Sciences
, 117(7), 3568-3574.
Zhu Jinsheng, Lau Kelvin, Puschmann Robert, Harmel Robert K, Zhang Youjun, Pries Verena, Gaugler Philipp, Broger Larissa, Dutta Amit K, Jessen Henning J, Schaaf Gabriel, Fernie Alisdair R, Hothorn Ludwig A, Fiedler Dorothea, Hothorn Michael (2019), Two bifunctional inositol pyrophosphate kinases/phosphatases control plant phosphate homeostasis, in eLife
, 8, 1-25.
Inorganic phosphate (Pi) is an essential and limiting nutrient for all eukaryotes. The cytosolic concentration of Pi determines the energetics of metabolic reactions that use, for example, ATP. Hydrolysis of its phosphoanhydride bonds can only provide sufficient energy to drive metabolic reactions if cytosolic Pi concentrations remain low. At the same time, the cytosol must provide sufficient Pi to allow for the synthesis of DNA, RNA, membranes and the phosphorylation of proteins and metabolites. Therefore, cells tightly control cytosolic Pi levels. Here, we propose to elucidate novel signal transduction pathways that mediate this control and study the properties of their key components in mechanistic detail.Cytosolic Pi concentrations depend on the activity of membrane-localized Pi importers and exporters, and on enzymes storing or consuming Pi, many of which contain SPX domains. We have recently uncovered that these domains represent cellular sensors for inositol pyrophosphates (PP-InsPs), a class of eukaryotic signaling molecules whose concentrations change in response to Pi availability. PP-InsPs bind to a conserved basic surface patch in SPX and render the domain competent to interact with down-stream signaling partners, for example Pi starvation responsive transcription factors in plants. Thus, PP-InsPs appear to communicate cytosolic Pi levels via SPX domains to a multitude of proteins to regulate Pi uptake, transport and storage.We now want to combine organic chemistry, biophysics, biochemistry and genetics to uncover the PP-InsP-controlled Pi signaling pathways in plants and in yeast. Specifically, we propose to study how PP-InsP binding affects SPX protein dynamics, allowing the domain to interact with and regulate down-stream target proteins. We will develop synthetic strategies to produce matrix-coupled PP-InsPs to affinity-purify stereoisomer-specific signaling complexes from yeast cells and different plant tissues. We will also design novel PP-InsP variants to allow for covalent trapping of low affinity and/or low-abundance PP-InsP-containing protein complexes. Forward and reverse genetic screens in Arabidopsis and in yeast will be used to uncover further elements of these Pi signaling pathways. Finally, we aim to dissect how changing Pi levels are translated into changes of PP-InsP concentrations in plant and yeast cells.Our integrated approach will likely uncover previously uncharacterized signaling cascades for intracellular Pi homeostasis in mechanistic detail and produce novel chemical and genetic tools to study Pi signaling. An exciting future application of our work may be the creation of transgenic crops with optimized Pi metabolism.