title: PTPN13 regulates cellular signalling and β-catenin function during megakaryocytic differentiation.
abstract: PTPN13 is a high-molecular weight intracellular phosphatase with several isoforms that exhibits a highly modular structure. Although in recent years different roles have been described for PTPN13, we are still far from understanding its function in cell biology. Here we show that PTPN13 expression is activated during megakaryocytic differentiation at the protein and mRNA level. Our results show that the upregulation of PTPN13 inhibits megakaryocytic differentiation, while PTPN13 silencing triggers differentiation. The ability of PTPN13 to alter megakaryocytic differentiation can be explained by its capacity to regulate ERK and STAT signalling. Interestingly, the silencing of β-catenin produced the same effect as PTPN13 downregulation. We demonstrate that both proteins coimmunoprecipitate and colocalise. Moreover, we provide evidence showing that PTPN13 can regulate β-catenin phosphorylation, stability and transcriptional activity. Therefore, the ability of PTPN13 to control megakaryocytic differentiation must be intimately linked to the regulation of β-catenin function. Moreover, our results show for the first time that PTPN13 is stabilised upon Wnt signalling, which makes PTPN13 an important player in canonical Wnt signalling. Our results show that PTPN13 behaves as an important regulator of megakaryocytic differentiation in cell lines and also in murine haematopoietic progenitors. This importance can be explained by the ability of PTPN13 to regulate cellular signalling, and especially through the regulation of β-catenin stability and function. Our results hold true for different megakaryocytic cell lines and also for haematopoietic progenitors, suggesting that these two proteins may play a relevant role during in vivo megakaryopoiesis.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Salamanca, Salamanca, Spain; IBFG, Instituto de Biología Funcional y Genómica, CSIC, Salamanca 37007, Spain.
authors.forename: José L
authors.initials: JL
authors.lastname: Sardina
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Salamanca, Salamanca, Spain; IBSAL (Instituto de Investigación Biomédica de Salamanca), Salamanca 37007, Spain.
authors.forename: Guillermo
authors.initials: G
authors.lastname: López-Ruano
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Salamanca, Salamanca, Spain; IBSAL (Instituto de Investigación Biomédica de Salamanca), Salamanca 37007, Spain.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Prieto-Bermejo
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Salamanca, Salamanca, Spain; IBSAL (Instituto de Investigación Biomédica de Salamanca), Salamanca 37007, Spain.
authors.forename: Beatriz
authors.initials: B
authors.lastname: Sánchez-Sánchez
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Salamanca, Salamanca, Spain; IBSAL (Instituto de Investigación Biomédica de Salamanca), Salamanca 37007, Spain.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Pérez-Fernández
authors.affiliation: Department of Hematology, Hospital Universitario Virgen del Rocío/IBIS/CSIC/University of Seville, Spain.
authors.forename: Luis Ignacio
authors.initials: LI
authors.lastname: Sánchez-Abarca
authors.affiliation: Department of Hematology, Hospital Universitario Virgen del Rocío/IBIS/CSIC/University of Seville, Spain.
authors.forename: José Antonio
authors.initials: JA
authors.lastname: Pérez-Simón
authors.affiliation: IBFG, Instituto de Biología Funcional y Genómica, CSIC, Salamanca 37007, Spain.
authors.forename: Luis
authors.initials: L
authors.lastname: Quintales
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Salamanca, Salamanca, Spain.
authors.forename: Jesús
authors.initials: J
authors.lastname: Sánchez-Yagüe
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Salamanca, Salamanca, Spain; IBSAL (Instituto de Investigación Biomédica de Salamanca), Salamanca 37007, Spain.
authors.forename: Marcial
authors.initials: M
authors.lastname: Llanillo
authors.affiliation: IBFG, Instituto de Biología Funcional y Genómica, CSIC, Salamanca 37007, Spain.
authors.forename: Francisco
authors.initials: F
authors.lastname: Antequera
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Salamanca, Salamanca, Spain; IBSAL (Instituto de Investigación Biomédica de Salamanca), Salamanca 37007, Spain. Electronic address: angelhh@usal.es.
authors.forename: Angel
authors.initials: A
authors.lastname: Hernández-Hernández
keywords: Hematopoiesis; Megakaryopoiesis; PTPN13; Wnt signalling; β-Catenin