Leukemia inhibitory factor-induced phosphorylation of STAP-2 on tyrosine-250 is involved in its STAT3-enhancing activity

Yuichi Sekine, Satoshi Tsuji, Osamu Ikeda, Michinori Kakisaka, Kenji Sugiyama, Akihiko Yoshimura, Tadashi Matsuda

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9 Citations (Scopus)


Signal transducing adaptor protein-2 (STAP-2) is a recently identified adaptor protein that contains Pleckstrin and Src homology 2 (SH2)-like domains as well as a YXXQ motif in its C-terminal region. Our previous studies revealed that STAP-2 binds to signal transducer and activator of transcription 3 (STAT3) and STAT5, and regulates their signaling pathways. In the present study, we identified tyrosine-250 (Tyr250) in STAP-2 as a major site of phosphorylation by v-src and Jak2, using a phospho-specific antibody against STAP-2 phosphorylated at Tyr250. Mutational analyses revealed that Tyr250 was involved in the STAT3-enhancing activity of STAP-2. We further found that leukemia inhibitory factor (LIF) stimulated STAP-2 Tyr250 phosphorylation in 293T and Hep3B cells. Moreover, endogenous STAP-2 was phosphorylated at Tyr250 following LIF stimulation of murine M1 cell line. Taken together, our findings demonstrate that endogenous STAP-2 is phosphorylated at Tyr250 and that this phosphorylation is involved in its function.

Original languageEnglish
Pages (from-to)517-522
Number of pages6
JournalBiochemical and Biophysical Research Communications
Issue number2
Publication statusPublished - 2007 May 4
Externally publishedYes



  • Adaptor protein
  • Antibody
  • LIF
  • Phosphorylation
  • STAP-2
  • STAT3
  • Transcription

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

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