title: Real-time dynamics of peptide ligand-dependent receptor complex formation in planta.
abstract: The CLAVATA (CLV) and flagellin (flg) signaling pathways act through peptide ligands and closely related plasma membrane-localized receptor-like kinases (RLKs). The plant peptide CLV3 regulates stem cell homeostasis, whereas the bacterial flg22 peptide elicits defense responses. We applied multiparameter fluorescence imaging spectroscopy (MFIS) to characterize the dynamics of RLK complexes in the presence of ligand in living plant cells expressing receptor proteins fused to fluorescent proteins. We found that the CLV and flg pathways represent two different principles of signal transduction: flg22 first triggered RLK heterodimerization and later assembly into larger complexes through homomerization. In contrast, CLV receptor complexes were preformed, and ligand binding stimulated their clustering. This different behavior likely reflects the nature of these signaling pathways. Pathogen-triggered flg signaling impedes plant growth and development; therefore, receptor complexes are formed only in the presence of ligand. In contrast, CLV3-dependent stem cell homeostasis continuously requires active signaling, and preformation of receptor complexes may facilitate this task.
authors.affiliation: Institute for Developmental Genetics and Cluster of Excellence in Plant Sciences, Heinrich-Heine University, Universitätsstraße 1, D-40225 Düsseldorf, Germany.
authors.forename: Marc
authors.initials: M
authors.lastname: Somssich
authors.affiliation: Chair for Molecular Physical Chemistry, Heinrich-Heine University, D-40225 Düsseldorf, Germany.
authors.forename: Qijun
authors.initials: Q
authors.lastname: Ma
authors.affiliation: Center for Advanced Imaging, Heinrich-Heine University, D-40225 Düsseldorf, Germany.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Weidtkamp-Peters
authors.affiliation: Institute for Developmental Genetics and Cluster of Excellence in Plant Sciences, Heinrich-Heine University, Universitätsstraße 1, D-40225 Düsseldorf, Germany.
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Stahl
authors.affiliation: Chair for Molecular Physical Chemistry, Heinrich-Heine University, D-40225 Düsseldorf, Germany.
authors.forename: Suren
authors.initials: S
authors.lastname: Felekyan
authors.affiliation: Institute for Developmental Genetics and Cluster of Excellence in Plant Sciences, Heinrich-Heine University, Universitätsstraße 1, D-40225 Düsseldorf, Germany.
authors.forename: Andrea
authors.initials: A
authors.lastname: Bleckmann
authors.affiliation: Chair for Molecular Physical Chemistry, Heinrich-Heine University, D-40225 Düsseldorf, Germany. Center for Advanced Imaging, Heinrich-Heine University, D-40225 Düsseldorf, Germany. ruediger.simon@hhu.de cseidel@hhu.de.
authors.forename: Claus A M
authors.initials: CA
authors.lastname: Seidel
authors.affiliation: Institute for Developmental Genetics and Cluster of Excellence in Plant Sciences, Heinrich-Heine University, Universitätsstraße 1, D-40225 Düsseldorf, Germany. Center for Advanced Imaging, Heinrich-Heine University, D-40225 Düsseldorf, Germany. ruediger.simon@hhu.de cseidel@hhu.de.
authors.forename: Rüdiger
authors.initials: R
authors.lastname: Simon
mesh_terms: D000595:Amino Acid Sequence; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D005408:Flagellin / Q000235:genetics / Q000378:metabolism; D005454:Fluorescence Polarization; D031541:Fluorescence Resonance Energy Transfer; D006706:Homeostasis; D008024:Ligands; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D018613:Microscopy, Confocal; D008969:Molecular Sequence Data; D010455:Peptides / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D014026:Nicotiana / Q000235:genetics / Q000378:metabolism*
chemical_list: C118167:AT2G27250 protein, Arabidopsis; D029681:Arabidopsis Proteins; D008024:Ligands; D008164:Luminescent Proteins; D010455:Peptides; D005408:Flagellin; D017346:Protein Serine-Threonine Kinases