NDP kinase 2 interacts with two oxidative stress-activated MAPKs to regulate cellular redox state and enhances multiple stress tolerance in transgenic plants.
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.
Moon
Haejeong
H
Division of Applied Life Science (BK21 Program), and Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 660-701, Korea.
Lee
Boyoung
B
Choi
Giltsu
G
Shin
Dongjin
D
Prasad
D Theertha
DT
Lee
Oksun
O
Kwak
Sang-Soo
SS
Kim
Doh Hoon
DH
Nam
Jaesung
J
Bahk
Jeongdong
J
Hong
Jong Chan
JC
Lee
Sang Yeol
SY
Cho
Moo Je
MJ
Lim
Chae Oh
CO
Yun
Dae-Jin
DJ
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
D011993:Recombinant Fusion Proteins; D020928:Mitogen-Activated Protein Kinases; C121988:nucleoside diphosphate kinase 2; D009701:Nucleoside-Diphosphate Kinase