title: Molecular characterization of the cytoplasmic interacting protein of the receptor kinase IRK expressed in the inflorescence and root apices of Arabidopsis.
abstract: Meristem maintenance and differentiation is regulated by intercellular communication through receptor-like kinases (RLKs) in plants, but the underlying molecular mechanisms of RLK signaling remain largely unknown. A cytoplasmic interactor for inflorescence and root apices receptor-like kinase (IRK), which is a typical meristematic RLK with leucine-rich repeats in Arabidopsis, was identified using a yeast two-hybrid assay and named IRK-interacting protein (IRKI). IRKI is a novel but highly conserved protein found in higher plants. The interaction between IRK and IRKI was confirmed by an in vitro pull-down assay and supported by their simultaneous expression in actively dividing cells in meristems. In the root tip, IRKI expression and localization visualized by green fluorescence protein (GFP) were observed in the quiescent center, initial cells, and immature stele cells. IRKI expression was expanded by exogenous auxin treatment and repressed by inhibitor treatment of polar auxin transport.
authors.affiliation: Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Nara 630-0192, Japan.
authors.forename: Junichiro
authors.initials: J
authors.lastname: Hattan
authors.forename: Hirosuke
authors.initials: H
authors.lastname: Kanamoto
authors.forename: Miho
authors.initials: M
authors.lastname: Takemura
authors.forename: Akiho
authors.initials: A
authors.lastname: Yokota
authors.forename: Takayuki
authors.initials: T
authors.lastname: Kohchi
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000166:cytology; D029681:Arabidopsis Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D049109:Cell Proliferation; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D049452:Green Fluorescent Proteins; D007210:Indoleacetic Acids / Q000494:pharmacology; D018519:Meristem / Q000737:chemistry / Q000166:cytology; D008969:Molecular Sequence Data; D018517:Plant Roots / Q000737:chemistry*; D011485:Protein Binding; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D015398:Signal Transduction; D014162:Transfection; D020798:Two-Hybrid System Techniques
chemical_list: D029681:Arabidopsis Proteins; D002352:Carrier Proteins; C501232:IRKI protein, Arabidopsis; D007210:Indoleacetic Acids; D049452:Green Fluorescent Proteins; D011494:Protein Kinases