title: NDP kinase 2 interacts with two oxidative stress-activated MAPKs to regulate cellular redox state and enhances multiple stress tolerance in transgenic plants.
abstract: NDP kinases (NDPKs) are multifunctional proteins that regulate a variety of eukaryotic cellular activities, including cell proliferation, development, and differentiation. However, much less is known about the functional significance of NDPKs in plants. We show here that NDPK is associated with H(2)O(2)-mediated mitogen-activated protein kinase signaling in plants. H(2)O(2) stress strongly induces the expression of the NDPK2 gene in Arabidopsis thaliana (AtNDPK2). Proteins from transgenic plants overexpressing AtNDPK2 showed high levels of autophosphorylation and NDPK activity, and they have lower levels of reactive oxygen species (ROS) than wild-type plants. Mutants lacking AtNDPK2 had higher levels of ROS than wild type. H(2)O(2) treatment induced the phosphorylation of two endogenous proteins whose molecular weights suggested they are AtMPK3 and AtMPK6, two H(2)O(2)-activated A. thaliana mitogen-activated protein kinases. In the absence of H(2)O(2) treatment, phosphorylation of these proteins was slightly elevated in plants overexpressing AtNDPK2 but markedly decreased in the AtNDPK2 deletion mutant. Yeast two-hybrid and in vitro protein pull-down assays revealed that AtNDPK2 specifically interacts with AtMPK3 and AtMPK6. Furthermore, AtNDPK2 also enhances the myelin basic protein phosphorylation activity of AtMPK3 in vitro. Finally, constitutive overexpression of AtNDPK2 in Arabidopsis plants conferred an enhanced tolerance to multiple environmental stresses that elicit ROS accumulation in situ. Thus, AtNDPK2 appears to play a previously uncharacterized regulatory role in H(2)O(2)-mediated MAPK signaling in plants.
authors.affiliation: Division of Applied Life Science (BK21 Program), and Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 660-701, Korea.
authors.forename: Haejeong
authors.initials: H
authors.lastname: Moon
authors.forename: Boyoung
authors.initials: B
authors.lastname: Lee
authors.forename: Giltsu
authors.initials: G
authors.lastname: Choi
authors.forename: Dongjin
authors.initials: D
authors.lastname: Shin
authors.forename: D Theertha
authors.initials: DT
authors.lastname: Prasad
authors.forename: Oksun
authors.initials: O
authors.lastname: Lee
authors.forename: Sang-Soo
authors.initials: SS
authors.lastname: Kwak
authors.forename: Doh Hoon
authors.initials: DH
authors.lastname: Kim
authors.forename: Jaesung
authors.initials: J
authors.lastname: Nam
authors.forename: Jeongdong
authors.initials: J
authors.lastname: Bahk
authors.forename: Jong Chan
authors.initials: JC
authors.lastname: Hong
authors.forename: Sang Yeol
authors.initials: SY
authors.lastname: Lee
authors.forename: Moo Je
authors.initials: MJ
authors.lastname: Cho
authors.forename: Chae Oh
authors.initials: CO
authors.lastname: Lim
authors.forename: Dae-Jin
authors.initials: DJ
authors.lastname: Yun
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000502:physiology*; D007700:Kinetics; D018613:Microscopy, Confocal; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009701:Nucleoside-Diphosphate Kinase / Q000378:metabolism*; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D010766:Phosphorylation; D030821:Plants, Genetically Modified / Q000201:enzymology / Q000502:physiology*; D011993:Recombinant Fusion Proteins
chemical_list: D011993:Recombinant Fusion Proteins; D020928:Mitogen-Activated Protein Kinases; C121988:nucleoside diphosphate kinase 2; D009701:Nucleoside-Diphosphate Kinase