title: Moderation of Arabidopsis root stemness by CLAVATA1 and ARABIDOPSIS CRINKLY4 receptor kinase complexes.
abstract: BACKGROUND
  The root system of higher plants originates from the activity of a root meristem, which comprises a group of highly specialized and long-lasting stem cells. Their maintenance and number is controlled by the quiescent center (QC) cells and by feedback signaling from differentiated cells. Root meristems may have evolved from structurally distinct shoot meristems; however, no common player acting in stemness control has been found so far.
  
  
  RESULTS
  We show that CLAVATA1 (CLV1), a key receptor kinase in shoot stemness maintenance, performs a similar but distinct role in root meristems. We report that CLV1 is signaling, activated by the peptide ligand CLAVATA3/EMBRYO SURROUNDING REGION40 (CLE40), together with the receptor kinase ARABIDOPSIS CRINKLY4 (ACR4) to restrict root stemness. Both CLV1 and ACR4 overlap in their expression domains in the distal root meristem and localize to the plasma membrane (PM) and plasmodesmata (PDs), where ACR4 preferentially accumulates. Using multiparameter fluorescence image spectroscopy (MFIS), we show that CLV1 and ACR4 can form homo- and heteromeric complexes that differ in their composition depending on their subcellular localization.
  
  
  CONCLUSIONS
  We hypothesize that these homo- and heteromeric complexes may differentially regulate distal root meristem maintenance. We conclude that essential components of the ancestral shoot stemness regulatory system also act in the root and that the specific interaction of CLV1 with ACR4 serves to moderate and control stemness homeostasis in the root meristem. The structural differences between these two meristem types may have necessitated this recruitment of ACR4 for signaling by CLV1.
authors: Institute of Developmental Genetics, Heinrich Heine University, 40225 Düsseldorf, Germany. yvonne.stahl@hhu.de
authors: Yvonne
authors: Y
authors: Stahl
authors: Stephanie
authors: S
authors: Grabowski
authors: Andrea
authors: A
authors: Bleckmann
authors: Ralf
authors: R
authors: Kühnemuth
authors: Stefanie
authors: S
authors: Weidtkamp-Peters
authors: Karine Gustavo
authors: KG
authors: Pinto
authors: Gwendolyn K
authors: GK
authors: Kirschner
authors: Julia B
authors: JB
authors: Schmid
authors: René H
authors: RH
authors: Wink
authors: Adrian
authors: A
authors: Hülsewede
authors: Suren
authors: S
authors: Felekyan
authors: Claus A M
authors: CA
authors: Seidel
authors: Rüdiger
authors: R
authors: Simon
mesh_terms: D017360:Arabidopsis / Q000201:enzymology* / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000378:metabolism*; D031541:Fluorescence Resonance Energy Transfer; D018519:Meristem / Q000201:enzymology / Q000254:growth & development*; D018517:Plant Roots / Q000201:enzymology / Q000254:growth & development*; D031425:Plasmodesmata / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D020794:Receptor Protein-Tyrosine Kinases / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D011956:Receptors, Cell Surface; D020794:Receptor Protein-Tyrosine Kinases; C462019:ACR4 protein, Arabidopsis; C118166:CLV1 protein, Arabidopsis; D017346:Protein Serine-Threonine Kinases