title: Regulation of abiotic stress signalling by Arabidopsis C-terminal domain phosphatase-like 1 requires interaction with a k-homology domain-containing protein.
abstract: Arabidopsis thaliana CARBOXYL-TERMINAL DOMAIN (CTD) PHOSPHATASE-LIKE 1 (CPL1) regulates plant transcriptional responses to diverse stress signals. Unlike typical CTD phosphatases, CPL1 contains two double-stranded (ds) RNA binding motifs (dsRBMs) at its C-terminus. Some dsRBMs can bind to dsRNA and/or other proteins, but the function of the CPL1 dsRBMs has remained obscure. Here, we report identification of REGULATOR OF CBF GENE EXPRESSION 3 (RCF3) as a CPL1-interacting protein. RCF3 co-purified with tandem-affinity-tagged CPL1 from cultured Arabidopsis cells and contains multiple K-homology (KH) domains, which were predicted to be important for binding to single-stranded DNA/RNA. Yeast two-hybrid, luciferase complementation imaging, and bimolecular fluorescence complementation analyses established that CPL1 and RCF3 strongly associate in vivo, an interaction mediated by the dsRBM1 of CPL1 and the KH3/KH4 domains of RCF3. Mapping of functional regions of CPL1 indicated that CPL1 in vivo function requires the dsRBM1, catalytic activity, and nuclear targeting of CPL1. Gene expression profiles of rcf3 and cpl1 mutants were similar during iron deficiency, but were distinct during the cold response. These results suggest that tethering CPL1 to RCF3 via dsRBM1 is part of the mechanism that confers specificity to CPL1-mediated transcriptional regulation.
authors.affiliation: Department of Horticultural Sciences, Texas A&M University, College Station, Texas, United States of America ; Division of Applied Life Science (BK21 Program), Graduate School of Gyeongsang National University, Jinju, Gyeongsangnam-do, Korea.
authors.forename: In Sil
authors.initials: IS
authors.lastname: Jeong
authors.forename: Akihito
authors.initials: A
authors.lastname: Fukudome
authors.forename: Emre
authors.initials: E
authors.lastname: Aksoy
authors.forename: Woo Young
authors.initials: WY
authors.lastname: Bang
authors.forename: Sewon
authors.initials: S
authors.lastname: Kim
authors.forename: Qingmei
authors.initials: Q
authors.lastname: Guan
authors.forename: Jeong Dong
authors.initials: JD
authors.lastname: Bahk
authors.forename: Kimberly A
authors.initials: KA
authors.lastname: May
authors.forename: William K
authors.initials: WK
authors.lastname: Russell
authors.forename: Jianhua
authors.initials: J
authors.lastname: Zhu
authors.forename: Hisashi
authors.initials: H
authors.lastname: Koiwa
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D020134:Catalytic Domain; D018506:Gene Expression Regulation, Plant; D008969:Molecular Sequence Data; D019913:Nuclear Localization Signals; D009997:Osmotic Pressure; D010446:Peptide Fragments / Q000737:chemistry; D010749:Phosphoprotein Phosphatases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D015398:Signal Transduction; D013312:Stress, Physiological; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D019913:Nuclear Localization Signals; D010446:Peptide Fragments; C584805:RCF3 protein, Arabidopsis; D016601:RNA-Binding Proteins; D014157:Transcription Factors; C465438:CPL1 protein, Arabidopsis; D010749:Phosphoprotein Phosphatases