Pin1 is required for the Ser727 phosphorylation-dependent Stat3 activity

C. Lufei, T. H. Koh, T. Uchida, X. Cao

Research output: Contribution to journalArticlepeer-review

82 Citations (Scopus)


Signal transducer and activator of transcription 3 (Stat3) belongs to a family of latent cytoplasmic transcription factors important for cytokine signaling. Stat3 is constitutively activated in various tumors, and activated Stat3 itself also acts as an oncogene. Transcriptional activity of Stat3 is controlled by Tyr-phosphorylation, followed by dimerization and nuclear translocation. However, phosphorylation on Ser727 is indispensable for its maximal transcriptional activity with unclear mechanism. Here, we report that peptidyl-prolyl cis/trans isomerase 1 (Pin1), which specifically recognizes the pSer/Thr-Pro motifs on its target proteins, interacts with Stat3 upon cytokine/growth factor stimulation. Overexpression of Pin1 promotes Stat3 transcriptional activity and target gene expression, as well as recruitment of transcription coactivator, p300. These effects, however, were compromised in the Pin1-deficient cells, and were totally dependent on the Ser727 phosphorylation site. Finally, we showed that Pin1 enhances Stat3-mediated epithelial- mesenchymal transition in breast cancer cells induced by oncostatin M. Our data reveal a novel, Ser727 phosphorylation-dependent, post-translational regulation mechanism for Stat3.

Original languageEnglish
Pages (from-to)7656-7664
Number of pages9
Issue number55
Publication statusPublished - 2007 Dec 6
Externally publishedYes


  • Pin1
  • Serine phosphorylation
  • Stat3
  • Transcriptional activity

ASJC Scopus subject areas

  • Molecular Biology
  • Genetics
  • Cancer Research


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