Evidence for serine/threonine and histidine kinase activity in the tobacco ethylene receptor protein NTHK2

• Published in: Plant physiology (Bethesda) Vol. 136; no. 2; pp. 2971 - 2981
• Main Authors: Zhang, Z.G, Zhou, H.L, Chen, T, Gong, Y, Cao, W.H, Wang, Y.J, Zhang, J.S, Chen, S.Y
• Format: Journal Article
• Language: English
• Published: Rockville, MD American Society of Plant Biologists 01.10.2004; American Society of Plant Physiologists
• Subjects: Abscisic Acid - pharmacology; Amino Acid Sequence; amino acid sequences; Amino acids; Arabidopsis; Biological and medical sciences; Calcium Chloride - pharmacology; Cell physiology; Complementary DNA; Dehydration; enzyme activity; ethylene; Focus Issue on Ethylene; Fundamental and applied biological sciences. Psychology; gene expression regulation; Gene Expression Regulation, Plant - drug effects; Genetic mutation; Growth regulators; Histidine Kinase; Manganese - pharmacology; Metabolism; Molecular and cellular biology; Molecular Sequence Data; Nicotiana - enzymology; Nicotiana - metabolism; Nicotiana tabacum; nucleotide sequences; Phosphoamino acids; Phosphorylation; Plant cells; Plant growth; Plant Growth Regulators - pharmacology; Plant physiology and development; plant proteins; Plant Proteins - chemistry; Plant Proteins - genetics; Plant Proteins - metabolism; Plants; protein kinases; Protein Kinases - metabolism; Protein Serine-Threonine Kinases - metabolism; Receptors; Receptors, Cell Surface - chemistry; Receptors, Cell Surface - genetics; Receptors, Cell Surface - metabolism; Schizosaccharomyces; Seedlings - metabolism; Sequence Alignment; sequence analysis; Sequence Homology, Amino Acid; serine-threonine protein kinases; Signal transduction; Sodium chloride; Species Specificity; substrate specificity; Tobacco; Yeasts; Enzyme; Growth; Transferases; Ethylene; Nicotiana tabacum; Fungi; Arabidopsis thaliana; Characterization; Signal transduction; Enzymatic activity; Cruciferae; Kinase; Dicotyledones; Angiospermae; Development; Schizosaccharomyces pombe; Plant growth substance; Ascomycetes; Spermatophyta; Solanaceae; Experimental plant; Thallophyta; Biological receptor
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.103.034686

Ethylene plays important roles in plant growth, development, and stress responses. Two ethylene receptors, ETR1 from Arabidopsis and NTHK1 from tobacco (Nicotiana tabacum), have been found to have His kinase (HK) activity and Ser/Thr kinase activity, respectively, although both show similarity to bacterial two-component HK. Here, we report the characterization of another ethylene receptor homolog gene, NTHK2, from tobacco. This gene also encodes a HK-like protein and is induced by dehydration and CaCl2 but not significantly affected by NaCl and abscisic acid treatments. The biochemical properties of the yeast (Schizosaccharomyces pombe)-expressed NTHK2 domains were further characterized. We found that NTHK2 possessed Ser/Thr kinase activity in the presence of Mn(2+) and had HK activity in the presence of Ca(2+). Several lines of evidence supported this conclusion, including hydrolytic stability, phosphoamino acid analysis, mutation, deletion, and substrate analysis. These properties have implications in elucidation of the complexity of the ethylene signal transduction pathway and understanding of ethylene functions in plants.