title: LMW-PTP associates and dephosphorylates STAT5 interacting with its C-terminal domain.
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.
authors.affiliation: Department of Biochemical Sciences, University of Florence, Viale Morgagni 50, Florence 50134, Italy.
authors.forename: Stefania
authors.initials: S
authors.lastname: Rigacci
authors.forename: Doriana
authors.initials: D
authors.lastname: Talini
authors.forename: Andrea
authors.initials: A
authors.lastname: Berti
mesh_terms: D001665:Binding Sites; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000378:metabolism*; D007527:Isoenzymes / Q000737:chemistry* / Q000378:metabolism*; D008533:Megakaryocytes / Q000737:chemistry* / Q000378:metabolism*; D008894:Milk Proteins; D010766:Phosphorylation; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D017027:Protein Tyrosine Phosphatases / Q000737:chemistry* / Q000378:metabolism*; D050799:STAT5 Transcription Factor; D013329:Structure-Activity Relationship; D015534:Trans-Activators / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D004268:DNA-Binding Proteins; D007527:Isoenzymes; D008894:Milk Proteins; D050799:STAT5 Transcription Factor; D015534:Trans-Activators; D017027:Protein Tyrosine Phosphatases