Molecular cloning and characterization of a novel human protein phosphatase, LMW-DSP3.
Reversible phosphorylation is recognized to be a major mechanism for the control of intracellular events in eukaryotic cells. From a human fetal brain cDNA library, we isolated a cDNA clone encoding a novel dual specificity protein phosphatase, which showed 88% identity with previously reported mouse LMW-DSP3 at the amino acid level. The deduced protein had a single dual-specificity phosphatase catalytic domain, and lacked a cdc25 homology domain. LMW-DSP3 was expressed in the heart, lung, liver, and pancreas, and the expression level in the pancreas was highest. The LMW-DSP3 gene was located in human chromosome 2q32, and consisted of five exons spanning 21kb of human genomic DNA. LMW-DSP3 fused to GST showed phosphatase activity towards p-nitrophenyl phosphate which was optimal at pH 7.0 and 40 degrees C, and the activity was enhanced by Ca(2+) and Mn(2+). The phosphatase activity of LMW-DSP3 was inhibited by orthovanate. LMW-DSP3 showed phosphatase activity toward oligopeptides containing pSer/Thr and pTyr, indicating that LMW-DSP3 is a protein phosphatase with dual substrate specificity.
Cheng
Haipeng
H
State Key Laboratory of Genetic Engineering, School of Life Science, Institute of Genetics, Fudan University, 200433, Shanghai, PR China
Gao
Qi
Q
Jiang
Min
M
Ma
Yushu
Y
Ni
Xiaohua
X
Guo
Lingchen
L
Jin
Wei
W
Cao
Gentao
G
Ji
Chaoneng
C
Ying
Kang
K
Xu
Weiwen
W
Gu
Shaohua
S
Ma
Yuhong
Y
Xie
Yi
Y
Mao
Yumin
Y
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D020134:Catalytic Domain; D002889:Chromosomes, Human, Pair 2; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D054637:Dual-Specificity Phosphatases; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015870:Gene Expression; D006801:Humans; D008099:Liver / Q000378:metabolism; D008168:Lung / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009206:Myocardium / Q000378:metabolism; D009596:Nitrophenols / Q000378:metabolism; D009928:Organ Specificity; D009943:Organophosphorus Compounds / Q000378:metabolism; D010179:Pancreas / Q000378:metabolism; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity; D014638:Vanadates / Q000494:pharmacology; D020687:cdc25 Phosphatases / Q000378:metabolism
D018076:DNA, Complementary; D004791:Enzyme Inhibitors; D009596:Nitrophenols; D009943:Organophosphorus Compounds; C008644:nitrophenylphosphate; D014638:Vanadates; D010749:Phosphoprotein Phosphatases; C477223:DUSP19 protein, human; D054637:Dual-Specificity Phosphatases; D020687:cdc25 Phosphatases