LMW-PTP associates and dephosphorylates STAT5 interacting with its C-terminal domain

Biochem Biophys Res Commun. 2003 Dec 12;312(2):360-6. doi: 10.1016/j.bbrc.2003.10.126.

Abstract

Hematopoietic cells, particularly megakaryoblastic ones, display a high level of low M(r) phosphotyrosine protein phosphatase (LMW-PTP) expression; nevertheless, the role of this PTP in such cellular lineages has been scarcely investigated. Here, we demonstrate that LMW-PTP is able to associate and dephosphorylate signal transducer and activator of transcription-5 (STAT5) in DAMI megakaryocytic cells. Numerous researchers repeatedly hypothesized the association of a regulatory phosphotyrosine protein phosphatase with STAT5 C-terminus, but such phosphotyrosine protein phosphatase remained unknown. We show evidence indicating that the association of STAT5 and LMW-PTP does not exclusively involve the phosphatase active site and phosphotyrosine residue of STAT5, and we individuate an essential region of interaction at STAT5 C-terminus, coinciding with the previously hypothesized PTP-associating domain.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Binding Sites
  • Cell Line
  • DNA-Binding Proteins / chemistry*
  • DNA-Binding Proteins / metabolism*
  • Isoenzymes / chemistry*
  • Isoenzymes / metabolism*
  • Megakaryocytes / chemistry*
  • Megakaryocytes / metabolism*
  • Milk Proteins*
  • Phosphorylation
  • Protein Binding
  • Protein Structure, Tertiary
  • Protein Tyrosine Phosphatases / chemistry*
  • Protein Tyrosine Phosphatases / metabolism*
  • STAT5 Transcription Factor
  • Structure-Activity Relationship
  • Trans-Activators / chemistry*
  • Trans-Activators / metabolism*

Substances

  • DNA-Binding Proteins
  • Isoenzymes
  • Milk Proteins
  • STAT5 Transcription Factor
  • Trans-Activators
  • Protein Tyrosine Phosphatases