title: The activity of the wheat MAP kinase phosphatase 1 is regulated by manganese and by calmodulin.
abstract: MAPK phosphatases (MKPs) are negative regulators of MAPKs in eukaryotes and play key roles in the regulation of different cellular processes. However in plants, little is known about the regulation of these Dual Specific Phosphatases (DSPs) by Ca(2+) and calmodulin (CaM). Here, we showed that the wheat MKP (TMKP1) harboring a calmodulin (CaM) binding domain, binds to CaM in a Ca(2+)-dependent manner. In addition, TMKP1 exhibited a phosphatase activity in vitro that is specifically enhanced by Mn(2+) and to a lesser extent by Mg(2+), but without any synergistic effect between the two bivalent cations. Most interestingly, CaM/Ca(2+) complex inhibits the catalytic activity of TMKP1 in a CaM-dose dependent manner. However, in the presence of Mn(2+) this activity is enhanced by CaM/Ca(2+) complex. These dual regulatory effects seem to be mediated via interaction of CaM/Ca(2+) to the CaM binding domain in the C-terminal part of TMKP1. Such effects were not reported so far, and raise a possible role for CaM and Mn(2+) in the regulation of plant MKPs during cellular response to external signals.
authors.affiliation: Laboratory of Plant Protection and Improvement, Center of Biotechnology of Sfax, BP1177, 3018 Sfax, Tunisia; Université de Toulouse, UPS, UMR 5546, Laboratoire de Recherche en Sciences Végétales, BP 42617, F-31326 Castanet-Tolosan, France.
authors.forename: Mouna
authors.initials: M
authors.lastname: Ghorbel
authors.affiliation: Laboratory of Plant Protection and Improvement, Center of Biotechnology of Sfax, BP1177, 3018 Sfax, Tunisia.
authors.forename: Ikram
authors.initials: I
authors.lastname: Zaidi
authors.affiliation: Université de Toulouse, UPS, UMR 5546, Laboratoire de Recherche en Sciences Végétales, BP 42617, F-31326 Castanet-Tolosan, France; CNRS, UMR 5546, BP 42617, F-31326 Castanet-Tolosan, France.
authors.forename: Eugénie
authors.initials: E
authors.lastname: Robe
authors.affiliation: Université de Toulouse, UPS, UMR 5546, Laboratoire de Recherche en Sciences Végétales, BP 42617, F-31326 Castanet-Tolosan, France; CNRS, UMR 5546, BP 42617, F-31326 Castanet-Tolosan, France.
authors.forename: Benoit
authors.initials: B
authors.lastname: Ranty
authors.affiliation: Université de Toulouse, UPS, UMR 5546, Laboratoire de Recherche en Sciences Végétales, BP 42617, F-31326 Castanet-Tolosan, France; CNRS, UMR 5546, BP 42617, F-31326 Castanet-Tolosan, France.
authors.forename: Christian
authors.initials: C
authors.lastname: Mazars
authors.affiliation: Université de Toulouse, UPS, UMR 5546, Laboratoire de Recherche en Sciences Végétales, BP 42617, F-31326 Castanet-Tolosan, France; CNRS, UMR 5546, BP 42617, F-31326 Castanet-Tolosan, France. Electronic address: galaud@lrsv.ups-tlse.fr.
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Galaud
authors.affiliation: Laboratory of Plant Protection and Improvement, Center of Biotechnology of Sfax, BP1177, 3018 Sfax, Tunisia; University of Sfax, Institute of Biotechnology, BP "1175", 3038 Sfax, Tunisia. Electronic address: moez.hanin@cbs.rnrt.tn.
authors.forename: Moez
authors.initials: M
authors.lastname: Hanin
mesh_terms: D029681:Arabidopsis Proteins / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D002147:Calmodulin / Q000378:metabolism*; D054638:Dual Specificity Phosphatase 1 / Q000737:chemistry / Q000378:metabolism*; D008345:Manganese / Q000494:pharmacology*; D017434:Protein Structure, Tertiary; D014908:Triticum / Q000201:enzymology*
chemical_list: D029681:Arabidopsis Proteins; D002147:Calmodulin; D008345:Manganese; D054638:Dual Specificity Phosphatase 1; D002118:Calcium
keywords: Ca(2+); Calmodulin; Enzyme regulation; MAP kinase phosphatase; Mn(2+)