Purification and Characterization of ZmRIP1, a Novel Reductant-Inhibited Protein Tyrosine Phosphatase from Maize

• Published in: Plant physiology (Bethesda) 2012-06, Vol.159 (2), p.671-681
• Main Authors: Li, Bingbing, Zhao, Yanxia, Liang, Liyan, Ren, Huibo, Xing, Yu, Chen, Lin, Sun, Mingzhu, Wang, Yuanhua, Han, Yu, Jia, Haifeng, Huang, Conglin, Wu, Zhongyi, Jia, Wensuo
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Arabidopsis - genetics; Arabidopsis - metabolism; Arsenicals - pharmacology; Biological and medical sciences; Cell Biology and Signal Transduction; Cell Nucleus - genetics; Cell Nucleus - metabolism; Chloroplasts - genetics; Chloroplasts - metabolism; Cloning, Molecular; Cysteine - metabolism; Dithiothreitol - pharmacology; Electrophoresis, Polyacrylamide Gel; Enzyme Activation; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Plant; Glutathione Transferase - genetics; Glutathione Transferase - metabolism; Molecular Sequence Data; Oxidation-Reduction; Plant physiology and development; Plant Proteins - genetics; Plant Proteins - isolation & purification; Plant Proteins - metabolism; Plants, Genetically Modified - genetics; Plants, Genetically Modified - metabolism; Point Mutation; Protein Transport - drug effects; Protein Tyrosine Phosphatases - antagonists & inhibitors; Protein Tyrosine Phosphatases - genetics; Protein Tyrosine Phosphatases - metabolism; Protoplasts - metabolism; Signal Transduction; Zea mays - drug effects; Zea mays - enzymology; Zea mays - genetics
• ISSN: 0032-0889; 1532-2548; 1532-2548
• DOI: 10.1104/pp.111.191510

Protein tyrosine phosphatases (PTPases) have long been thought to be activated by reductants and deactivated by oxidants, owing to the presence of a crucial sulfhydryl group in their catalytic centers. In this article, we report the purification and characterization of Reductant-Inhibited PTPase1 (ZmRIP1) from maize (Zea mays) coleoptiles, and show that this PTPase has a unique mode of redox regulation and signaling. Surprisingly, ZmRIP1 was found to be deactivated by a reductant. A cysteine (Cys) residue (Cys-181) near the active center was found to regulate this unique mode of redox regulation, as mutation of Cys-181 to arginine-181 allowed ZmRIP1 to be activated by a reductant. In response to oxidant treatment, ZmRIP1 was translocated from the chloroplast to the nucleus. Expression of ZmRIP1 in Arabidopsis (Arabidopsis thaliana) plants and maize protoplasts altered the expression of genes encoding enzymes involved in antioxidant catabolism, such as At1g02950, which encodes a glutathione transferase. Thus, the novel PTPase identified in this study is predicted to function in redox signaling in maize.