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          Institute: MPI für molekulare Pflanzenphysiologie     Collection: Publikationen Pflanzenphysiologie     Display Documents



  history
ID: 248411.0, MPI für molekulare Pflanzenphysiologie / Publikationen Pflanzenphysiologie
Arabidopsis AtDGK7, the smallest member of plant diacylglycerol kinases (DGKs), displays unique biochemical features and saturates at low substrate concentration - The DGK inhibitor R59022 differentially affects AtDGK2 and AtDGK7 activity in vitro and alters plant growth and development
Authors:Gomez-Merino, F. C.; Arana-Ceballos, F. A.; Trejo-Tellez, L. I.; Skirycz, A.; Brearley, C. A.; Dormann, P.; Mueller-Roeber, B.
Language:English
Date of Publication (YYYY-MM-DD):2005-10-14
Title of Journal:Journal of Biological Chemistry
Journal Abbrev.:J Biol Chem
Volume:280
Issue / Number:41
Start Page:34888
End Page:34899
Review Status:not specified
Audience:Not Specified
Abstract / Description:Diacylglycerol kinase (DGK) regulates the level of the second messenger diacylglycerol and produces phosphatidic acid (PA), another signaling molecule. The Arabidopsis thaliana genome encodes seven putative diacylglycerol kinase isozymes (named AtDGK1 to -7), structurally falling into three major clusters. So far, enzymatic activity has not been reported for any plant Cluster II DGK. Here, we demonstrate that a representative of this cluster, AtDGK7, is biochemically active when expressed as a recombinant protein in Escherichia coli. AtDGK7, encoded by gene locus At4g30340, contains 374 amino acids with an apparent molecular mass of 41.2 kDa. AtDGK7 harbors an N-terminal catalytic domain, but in contrast to various characterized DGKs (including AtDGK2), it lacks a cysteine-rich domain at its N terminus, and, importantly, its C-terminal DGK accessory domain is incomplete. Recombinant AtDGK7 expressed in E. coli exhibits Michaelis-Menten type kinetics with 1,2-dioleoyl-sn-glycerol as substrate. AtDGK7 activity was affected by pH, detergents, and the DGK inhibitor R59022. We demonstrate that both AtDGK2 and AtDGK7 phosphorylate diacylglycerol molecular species that are typically found in plants, indicating that both enzymes convert physiologically relevant substrates. AtDGK7 is expressed throughout the Arabidopsis plant, but expression is strongest in flowers and young seedlings. Expression of AtDGK2 is transiently induced by wounding. R59022 at similar to 80 mu M inhibits root elongation and lateral root formation and reduces plant growth, indicating that DGKs play an important role in plant development.
Free Keywords:pleckstrin homology domain
; phosphatidic-acid
; phospholipase-c
; plasma-membrane
; rich region
; cells
; protein
; phosphatidylinositol
; accumulation
; thaliana
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für molekulare Pflanzenphysiologie/Molekulare Physiologie/AG Doermann
MPI für molekulare Pflanzenphysiologie/Universitätsgastgruppen/AG Mueller-Roeber
External Affiliations:Univ Potsdam, Inst Biochem & Biol, Karl Liebknecht Str 24-25,Haus 20, D-14476 Golm Potsdam, Germany
Univ Potsdam, Inst Biochem & Biol, D-14476 Golm Potsdam, Germany
Coll Postgrad Agr Sci, Montecillo 56230, Mexico
Univ E Anglia, Sch Biol Sci, Norwich NR4 7TJ, Norfolk, England
Max Planck Inst Mol Plant Physiol, Dept Mol Physiol, D-14476 Golm Potsdam, Germany
Max Planck Inst Mol Plant Physiol, Cooperat Res Grp, D-14476 Golm Potsdam, Germany
Identifiers:ISI:000232403900061 [ID No:1]
ISI:000232403900061 [ID No:2]
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