title: SHP-2 is a dual-specificity phosphatase involved in Stat1 dephosphorylation at both tyrosine and serine residues in nuclei.
abstract: Signal transducer and activator of transcription (STAT) proteins are both tyrosine- and serine-phosphorylated, mediating signal transduction and gene regulation. Following gene regulation, STAT activity in the nucleus is then terminated by a nuclear protein phosphatase(s), which remains unidentified. Using novel antibody arrays to screen the Stat1-specific protein phosphatase(s), we identified a SHP-2-Stat1 interaction in the A431 cell nucleus. SHP-2 and Stat1 nuclear localization and their association in response to either epidermal growth factor or interferon-gamma (IFNgamma) were confirmed by immunofluorescent staining and affinity precipitation assays. The SHP-2 C-terminal region containing protein-tyrosine phosphatase activity interacted with the C-terminal SH2 transcriptional activation domain of Stat1. In SHP-2-/- mouse fibroblast cells, Stat1 phosphorylation at both the tyrosine residue Tyr(701) and the serine residue Ser(727) by IFNgamma was enhanced and prolonged. Consistently, purified GST-SHP-2 dephosphorylated Stat1 at both tyrosine and serine residues when immunoprecipitated phospho-Stat1 or a peptide corresponding to the sequence surrounding Tyr(P)(701) or Ser(P)(727) of Stat1 was used as the substrate. Overexpression of SHP-2 in 293T cells inhibited IFNgamma-dependent Stat1 phosphorylation and suppressed Stat1-dependent induction of luciferase activity. Our findings demonstrate that SHP-2 is a dual-specificity protein phosphatase involved in Stat1 dephosphorylation at both tyrosine and serine residues and plays an important role in modulating STAT function in gene regulation.
authors.affiliation: Department of Pathology and Laboratory Medicine, Brown University School of Medicine, Providence, Rhode Island 02912, USA.
authors.forename: Tong R
authors.initials: TR
authors.lastname: Wu
authors.forename: Y Kate
authors.initials: YK
authors.lastname: Hong
authors.forename: Xu-Dong
authors.initials: XD
authors.lastname: Wang
authors.forename: Mike Y
authors.initials: MY
authors.lastname: Ling
authors.forename: Ana M
authors.initials: AM
authors.lastname: Dragoi
authors.forename: Alicia S
authors.initials: AS
authors.lastname: Chung
authors.forename: Andrew G
authors.initials: AG
authors.lastname: Campbell
authors.forename: Zhi-Yong
authors.initials: ZY
authors.lastname: Han
authors.forename: Gen-Sheng
authors.initials: GS
authors.lastname: Feng
authors.forename: Y Eugene
authors.initials: YE
authors.lastname: Chin
mesh_terms: D021581:Active Transport, Cell Nucleus; D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D002478:Cells, Cultured; D004247:DNA / Q000378:metabolism; D018076:DNA, Complementary / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D005347:Fibroblasts / Q000378:metabolism; D005786:Gene Expression Regulation; D005982:Glutathione Transferase / Q000378:metabolism; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins; D008156:Luciferases / Q000378:metabolism; D051379:Mice; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D010766:Phosphorylation; D011233:Precipitin Tests; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism* / Q000502:physiology*; D050794:STAT1 Transcription Factor; D017386:Sequence Homology, Amino Acid; D012694:Serine / Q000737:chemistry* / Q000378:metabolism; D013997:Time Factors; D015534:Trans-Activators / Q000378:metabolism*; D014407:Tumor Cells, Cultured; D014443:Tyrosine / Q000737:chemistry* / Q000378:metabolism
chemical_list: D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D047908:Intracellular Signaling Peptides and Proteins; D050794:STAT1 Transcription Factor; C494079:STAT1 protein, human; C494080:Stat1 protein, mouse; D015534:Trans-Activators; D014443:Tyrosine; D012694:Serine; D007371:Interferon-gamma; D004247:DNA; D008156:Luciferases; D005982:Glutathione Transferase; C516724:PTPN11 protein, human; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D017027:Protein Tyrosine Phosphatases; C516725:Ptpn11 protein, mouse