Expression of human protein tyrosine phosphatase epsilon in leucocytes: a potential ERK pathway-regulating phosphatase.
The expression of protein tyrosine phosphatase epsilon (PTPepsilon) was studied in human tissues and blood cells. High mRNA expression was observed in peripheral blood leucocytes, particularly in monocytes and granulocytes which revealed at least four distinct transcripts. In lymphocytes, PTPepsilon expression was induced after 12-O-tetradecanoylphorbol-13-acetate (TPA) or antigen-receptor stimulation, indicating that PTPepsilon plays a role in the events taking place after antigen engagement. Previously, PTPepsilon has been shown to be involved in regulating voltage-gated potassium channel activity, insulin-receptor signalling and Janus kinase-signal transducers and activators of transcription (STAT) signalling. Transfection of cells with different PTPepsilon constructs and activator protein-1 reporter gene indicates that the catalytic activity of PTPepsilon is involved in the regulation of the mitogen-activated protein kinase cascade. In particular, the extracellular signal-regulated kinases (ERK1/2) were shown to be inhibited in both phosphorylation status and enzymatic activity after overexpression of PTPepsilon. Thus, PTPepsilon emerges as a phosphatase with a potential to regulate the ERK1/2 pathway either directly or indirectly through its catalytic activity.
Department of Immunology, The Norwegian Radium Hospital, Oslo, Norway.
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Wabakken
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Hauge
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Finne
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Wiedlocha
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Aasheim
D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D005260:Female; D015870:Gene Expression / Q000187:drug effects; D018922:HL-60 Cells; D006801:Humans; D019169:Jurkat Cells; D007962:Leukocytes / Q000187:drug effects / Q000201:enzymology*; D008297:Male; D051379:Mice; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D008969:Molecular Sequence Data; D017027:Protein Tyrosine Phosphatases / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D054630:Receptor-Like Protein Tyrosine Phosphatases, Class 4; D017386:Sequence Homology, Amino Acid; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014018:Tissue Distribution
D012333:RNA, Messenger; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; C490825:PTPRE protein, human; D017027:Protein Tyrosine Phosphatases; C098067:Ptpre protein, mouse; C490826:Ptpre protein, rat; D054630:Receptor-Like Protein Tyrosine Phosphatases, Class 4; D013755:Tetradecanoylphorbol Acetate