Identification of a dual-specificity protein phosphatase that inactivates a MAP kinase from Arabidopsis.
Mitogen-activated protein kinases (MAPKs) play a key role in plant responses to stress and pathogens. Activation and inactivation of MAPKs involve phosphorylation and dephosphorylation on both threonine and tyrosine residues in the kinase domain. Here we report the identification of an Arabidopsis gene encoding a dual-specificity protein phosphatase capable of hydrolysing both phosphoserine/threonine and phosphotyrosine in protein substrates. This enzyme, designated AtDsPTP1 (Arabidopsis thaliana dual-specificity protein tyrosine phosphatase), dephosphorylated and inactivated AtMPK4, a MAPK member from the same plant. Replacement of a highly conserved cysteine by serine abolished phosphatase activity of AtDsPTP1, indicating a conserved catalytic mechanism of dual-specificity protein phosphatases from all eukaryotes.
Department of Plant and Microbial Biology, University of California at Berkeley 94720, USA.
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Gupta
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Huang
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Kieber
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Luan
D000595:Amino Acid Sequence; D000818:Animals; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics; D001483:Base Sequence; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000037:antagonists & inhibitors*; D020134:Catalytic Domain / Q000235:genetics; D017931:DNA Primers / Q000235:genetics; D018076:DNA, Complementary / Q000235:genetics; D018744:DNA, Plant / Q000235:genetics; D004791:Enzyme Inhibitors / Q000378:metabolism; D017343:Genes, Plant; D006801:Humans; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D017027:Protein Tyrosine Phosphatases / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity
D017931:DNA Primers; D018076:DNA, Complementary; D018744:DNA, Plant; D004791:Enzyme Inhibitors; D012333:RNA, Messenger; D018749:RNA, Plant; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D017027:Protein Tyrosine Phosphatases