ASG2 is a farnesylated DWD protein that acts as ABA negative regulator in Arabidopsis |
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Authors: | Christelle Dutilleul Iliana Ribeiro Nathalie Blanc Cynthia D. Nezames Xing Wang Deng Piotr Zglobicki Ana María Palacio Barrera Lucia Atehortùa Martine Courtois Valérie Labas Nathalie Giglioli‐Guivarc'h Eric Ducos |
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Affiliation: | 1. EA2106 ‘Biomolécules et Biotechnologies Végétales’, UFR des Sciences et Techniques, Université Fran?ois Rabelais de Tours, Tours, France;2. Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA;3. Department of Plant Biotechnology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland;4. Universidad de Antioquia, Laboratorio de Biotecnología, Sede de Investigación Universitaria, Medellín, Colombia;5. INRA, UMR85 Physiologie de la Reproduction et des Comportements, UMR CNRS 7247, UFR, IFC, Plate‐forme d'Analyse Intégrative des Biomolécules, Laboratoire de Spectrométrie de Masse, Nouzilly, France |
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Abstract: | The tagging‐via‐substrate approach designed for the capture of mammal prenylated proteins was adapted to Arabidopsis cell culture. In this way, proteins are in vivo tagged with an azide‐modified farnesyl moiety and captured thanks to biotin alkyne Click‐iT® chemistry with further streptavidin‐affinity chromatography. Mass spectrometry analyses identified four small GTPases and ASG2 (ALTERED SEED GERMINATION 2), a protein previously associated to the seed germination gene network. ASG2 is a conserved protein in plants and displays a unique feature that associates WD40 domains and tetratricopeptide repeats. Additionally, we show that ASG2 has a C‐terminal CaaX‐box that is farnesylated in vitro. Protoplast transfections using CaaX prenyltransferase mutants show that farnesylation provokes ASG2 nucleus exclusion. Moreover, ASG2 interacts with DDB1 (DAMAGE DNA BINDING protein 1), and the subcellular localization of this complex depends on ASG2 farnesylation status. Finally, germination and root elongation experiments reveal that asg2 and the farnesyltransferase mutant era1 (ENHANCED RESPONSE TO ABSCISIC ACID (ABA) 1) behave in similar manners when exposed to ABA or salt stress. To our knowledge, ASG2 is the first farnesylated DWD (DDB1 binding WD40) protein related to ABA response in Arabidopsis that may be linked to era1 phenotypes. |
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Keywords: | ABA signalling DDB1 CUL4 E3 ubiquitin ligase protein farnesylation tagging‐via‐substrate |
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