Molecular characterization of a tyrosine-specific protein phosphatase encoded by a stress-responsive gene in Arabidopsis

被引：134

作者：

Xu, Q ^{[1
]}

Fu, HH ^{[1
]}

Gupta, R ^{[1
]}

Luan, S ^{[1
]}

机构：

[1] Univ Calif Berkeley, Dept Plant & Microbial Biol, Berkeley, CA 94720 USA

来源：

PLANT CELL | 1998年 / 10卷 / 05期

关键词：

D O I：

10.1105/tpc.10.5.849

中图分类号：

Q5 [生物化学]; Q7 [分子生物学];

学科分类号：

071010 ; 081704 ;

摘要：

Protein tyrosine kinases and phosphatases play a vital role in the regulation of cell growth and differentiation in animal systems. However, none of these enzymes has been characterized from higher plants. In this study, we isolated a cDNA encoding a putative protein tyrosine phosphatase (PTPase) from Arabidopsis (referred to as AtPTP1). The expression level of AtPTP1 is highly sensitive to environmental stresses. High-salt conditions increased AtPTP1 mRNA levels, whereas cold treatment rapidly eliminated the AtPTP1 transcript. The recombinant AtPTP1 protein specifically hydrolyzed phosphotyrosine, but not phosphoserine/threonine, in protein substrates. Site-directed mutagenesis defined two highly conserved amino acids, cysteine-265 and aspartate-234, as being essential for the phosphatase activity of the AtPTP1 protein, suggesting a common catalytic mechanism for PTPases from all eukaryotic systems. In summary, we have identified AtPTP1 as a tyrosine-specific protein phosphatase that may function in stress responses of higher plants.

引用

页码：849 / 857

页数：9