Structural Biology & Cell Biology & Genetics

Plants are nature’s other successful experiment with multicellular life. We are interested in signaling and metabolic pathways that allow plants to grow and to develop. Our approach combines structural biology and biochemistry with cell biology and genetics in Arabidopsis.

Currently, we study how plant cells communicate with each other at their cell membrane, where they have evolved unique membrane receptor kinases. These receptors sense steroid and peptide hormones to orchestrate growth and development, to establish and maintain stem cell populations and to form plant organs and tissues. We have shown that these receptors require helper proteins for activation. We now want to obtain a molecular understanding of plant peptide hormone signaling and identify novel receptor complexes.

A second line of research is to understand how plants sense and store phosphate, an essential plant nutrient. We became interested in this topic by identifying a protein complex, which uses cytosolic ATP to generate long chains of inorganic polyphosphate, an important phosphate store in yeast. We have initiated a set of projects to test whether plants also make use of polyphosphates to store phosphate.

• Mechanistic insights into the regulation of plant phosphate homeostasis by the rice SPX2-PHR2 complex
  Guan, Zeyuan; Zhang, Qunxia; Zhang, Zhifei; Zuo, Jiaqi; Chen, Juan; et al.
  Nature Communications  10.1038/s41467-022-29275-8  MAR 24 2022
• Using Biotinylated myo-Inositol Hexakisphosphate to Investigate Inositol Pyrophosphate-Protein Interactions with Surface-Based Biosensors
  Couto, Daniel; Richter, Annika; Walter, Henriette; Furkert, David; Hothorn, Michael; et al.
  Biochemistry  10.1021/acs.biochem.1c00497  SEP 21 2021
• Signatures of antagonistic pleiotropy in a bacterial flagellin epitope
  Parys, Katarzyna; Colaianni, Nicholas R.; Lee, Ho-Seok; Hohmann, Ulrich; Edelbacher, Natalie; et al.
  Cell Host & Microbe  10.1016/j.chom.2021.02.008 Published: APR 14 2021
• A constitutively monomeric UVR8 photoreceptor confers enhanced UV-B photomorphogenesis
  Podolec, Roman; Lau, Kelvin; Wagnon, Timothee B.; Hothorn, Michael; Ulm, Roman
  Proceedings Of The National Academy Of Sciences Of The United States Of America   DOI: 10.1073/pnas.2017284118 FEB 9 2021
• Inositol pyrophosphates promote the interaction of SPX domains with the coiled-coil motif of PHR transcription factors to regulate plant phosphate homeostasis
  Ried, Martina K.; Wild, Rebekka; Zhu, Jinsheng; Pipercevic, Joka; Sturm, Kristina; et al.
  Nature Communications 10.1038/s41467-020-20681-4 JAN 15 2021
• Adjustment of the PIF7-HFR1 transcriptional module activity controls plant shade adaptation
  Paulisic, Sandi; Qin, Wenting; Veraszto, Harshul Arora; Then, Christiane; Alary, Benjamin; et al.
  Embo Journal 10.15252/embj.2019104273 JAN 4 2021
• BAM1/2 receptor kinase signaling drives CLE peptide-mediated formative cell divisions in Arabidopsis roots
  Crook, AD; Willoughby, AC; Hazak, O; Okuda, S; VanDerMolen, KR; Soyars, CL; Cattaneo, P; Clark, NM ; Sozzani, R; Hothorn, M; Hardtke, CS; Nimchuk, ZL
  Proceedings Of The National Academy Of Sciences Of The United States Of America 10.1073/pnas.2018565117 DEC 22 2020
• Constitutive Activation of Leucine-Rich Repeat Receptor Kinase Signaling Pathways by BAK1-INTERACTING RECEPTOR-LIKE KINASE3 Chimera([OPEN])
  Hohmann, Ulrich; Ramakrishna, Priya; Wang, Kai; Lorenzo-Orts, Laura; Nicolet, Joel; et al.
  Plant Cell  10.1105/tpc.20.00138  OCT 2020
• A two-way molecular dialogue between embryo and endosperm is required for seed development
  Doll, N. M.; Royek, S.; Fujita, S.; Okuda, S.; Chamot, S.; Stintzi, A; Widiez, T; Hothorn, M; Schaller, A; Geldner, N; Ingram, G
• Molecular mechanism for the recognition of sequence-divergent CIF peptides by the plant receptor kinases GSO1/SGN3 and GSO2
  Okuda, Satohiro; Fujita, Satoshi; Moretti, Andrea; Hohmann, Ulrich; Doblas, Veronica G.; Ma, Y; Pfister, A; Brandt, B; Geldner, N; Hothorn, M
  Proceedings Of The National Academy Of Sciences Of The United States Of America, 10.1073/pnas.1911553117, FEB 4 2020
• A genetically validated approach for detecting inorganic polyphosphates in plants
  Zhu, Jinsheng; Loubery, Sylvain; Broger, Larissa; Zhang, Youjun; Lorenzo-Orts, Laura; et al.
  Plant Journal, 10.1111/tpj.14642, JAN 2020
• Identity and functions of inorganic and inositol polyphosphates in plants
  Lorenzo-Orts, L; Couto, D; Hothorn, M
  NEW PHYTOLOGIST, 10.1111/nph.16129   2019
• Plant photoreceptors and their signaling components compete for COP1 binding via VP peptide motifs
  Lau, K; Podolec, R; Chappuis, R; Ulm, R; Hothorn, M
  EMBO JOURNAL, 38 (18):10.15252/embj.2019102140 SEP 16 2019
• Two bifunctional inositol pyrophosphate kinases/phosphatases control plant phosphate homeostasis
  Zhu, J; Lau, K; Puschmann, R; Harmel, RK; Zhang, YJ; Pries, V; Gaugler, P; Broger, L; Dutta, AK; Jessen, HJ; Schaaf, G; Fernie, AR; Hothorn, LA; Fiedler, D; Hothorn, M
  ELIFE, 8 10.7554/eLife.43582 AUG 22 2019
• …

• Plant membrane signaling
• Receptor kinases
• Brassinosteroid signaling
• Cytokinin signaling
• Polyphosphate metabolism
• Phosphate sensing

• Receptor agonist/antagonist development
• Structural Biology / Protein Crystallography of signaling proteins and metabolic enzymes
• Quantitative biochemistry. Protein-Protein interactions. Protein-Ligand interactions