title: N-terminal modifications contribute to flowering time and immune response regulations.
abstract: A variety of N-terminal co-translational modifications play crucial roles in many cellular processes across eukaryotic organisms. Recently, N-terminal acetylation has been proposed as a regulatory mechanism for the control of plant immunity. Analysis of an N-terminal acetyltransferase complex A (NatA) mutant, naa15-1, revealed that NatA controls the stability of immune receptor Suppressor of NPR1, Constitutive 1 (SNC1) in an antagonistic fashion with NatB. Here, we further report on an antagonistic regulation of flowering time by NatA and NatB, where naa15-1 plants exhibit late flowering, opposite of the early flowering phenotype previously observed in natB mutants. In addition, we provide evidence for the involvement of another N-terminal modification, N-myristoylation, in controlling pathogen-associated molecular pattern (PAMP) triggered immunity (PTI) through the characterization of N-myristoyltransferase 1 (NMT1) defective mutants, which express a low level of NMT1 protein. The mutant line lacks induced production of reactive oxygen species and MAP kinase phosphorylation in response to treatment with the known immune elicitor flg22. NMT1 deficient plants also exhibit increased susceptibility to Pst hrcC, a non-pathogenic Pseudomonas syringae tomato strain lacking a functional type-III secretion system. The potential for the NatA-NatB antagonistic relationship to exist outside of the regulation of SNC1 as well as the disclosing of NMT1s role in PTI further supports the significant contribution of N-terminal co-translational modifications in the regulation of biological processes in plants, and present interesting areas for further exploration.
authors.affiliation: a Michael Smith Laboratories; University of British Columbia ; British Columbia , Canada.|b Department of Botany ; University of British Columbia ; British Columbia , Canada.
authors.forename: Paul
authors.initials: P
authors.lastname: Kapos
authors.affiliation: a Michael Smith Laboratories; University of British Columbia ; British Columbia , Canada.|b Department of Botany ; University of British Columbia ; British Columbia , Canada.
authors.forename: Fang
authors.initials: F
authors.lastname: Xu
authors.affiliation: c Institute for Integrative Biology of the Cell (I2BC); CEA, CNRS, University Paris-Sud ; Gif sur Yvette , France.
authors.forename: Thierry
authors.initials: T
authors.lastname: Meinnel
authors.affiliation: c Institute for Integrative Biology of the Cell (I2BC); CEA, CNRS, University Paris-Sud ; Gif sur Yvette , France.
authors.forename: Carmela
authors.initials: C
authors.lastname: Giglione
authors.affiliation: a Michael Smith Laboratories; University of British Columbia ; British Columbia , Canada.|b Department of Botany ; University of British Columbia ; British Columbia , Canada.
authors.forename: Xin
authors.initials: X
authors.lastname: Li
mesh_terms: D000107:Acetylation; D000217:Acyltransferases / Q000235:genetics / Q000378:metabolism; D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism / Q000382:microbiology; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D035264:Flowers / Q000254:growth & development* / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D008780:Methyltransferases / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D063209:N-Terminal Acetyltransferase A / Q000235:genetics / Q000378:metabolism; D063210:N-Terminal Acetyltransferase B / Q000235:genetics / Q000378:metabolism; D000069452:Pathogen-Associated Molecular Pattern Molecules / Q000378:metabolism; D010641:Phenotype; D063245:Plant Development / Q000235:genetics*; D057865:Plant Immunity / Q000235:genetics*; D046188:Protein Modification, Translational; D044224:Pseudomonas syringae
chemical_list: D029681:Arabidopsis Proteins; D000069452:Pathogen-Associated Molecular Pattern Molecules; C482739:SNC1 protein, Arabidopsis; D008780:Methyltransferases; C419648:at3g18000 protein, Arabidopsis; D000217:Acyltransferases; D063209:N-Terminal Acetyltransferase A; D063210:N-Terminal Acetyltransferase B; C050480:glycylpeptide N-tetradecanoyltransferase
keywords: N-end Rule; N-terminal acetylation; N-terminal myristoylation; NMT; Nat; plant immunity; protein regulation