title: MVP-Associated Filamin A Mutations Affect FlnA-PTPN12 (PTP-PEST) Interactions.
abstract: Although the genetic basis of mitral valve prolapse (MVP) has now been clearly established, the molecular and cellular mechanisms involved in the pathological processes associated to a specific mutation often remain to be determined. TheFLNAgene (encoding Filamin A; FlnA) was the first gene associated to non-syndromic X-linked myxomatous valvular dystrophy, but the impacts of the mutations on its function remain un-elucidated. Here, using the first repeats (1-8) of FlnA as a bait in a yeast two-hybrid screen, we identified the tyrosine phosphatase PTPN12 (PTP-PEST) as a specific binding partner of this region of FlnA protein. In addition, using yeast two-hybrid trap assay pull down and co-immunoprecipitation experiments, we showed that the MVP-associated FlnA mutations (G288R, P637Q, H743P) abolished FlnA/PTPN12 interactions. PTPN12 is a key regulator of signaling pathways involved in cell-extracellular matrix (ECM) crosstalk, cellular responses to mechanical stress that involve integrins, focal adhesion transduction pathways, and actin cytoskeleton dynamics. Interestingly, we showed that the FlnA mutations impair the activation status of two PTPN12 substrates, the focal adhesion associated kinase Src, and the RhoA specific activating protein p190RhoGAP. Together, these data point to PTPN12/FlnA interaction and its weakening by FlnA mutations as a mechanism potentially involved in the physiopathology of FlnA-associated MVP.
authors.affiliation: Institut du thorax, Inserm UMR 1087, CNRS UMR 6291, 8 Quai Moncousu, Nantes F-44007, France; damien.duval@etu.univ-nantes.fr (D.D.); pauline.labbe@etu.univ-nantes.fr (P.L.); bureau.lea@gmail.com (L.B.); thletourneau@yahoo.fr (T.L.T.); jjschott@univ-nantes.fr (J.-J.S.).
authors.forename: Damien
authors.initials: D
authors.lastname: Duval
authors.affiliation: Institut du thorax, Inserm UMR 1087, CNRS UMR 6291, 8 Quai Moncousu, Nantes F-44007, France; damien.duval@etu.univ-nantes.fr (D.D.); pauline.labbe@etu.univ-nantes.fr (P.L.); bureau.lea@gmail.com (L.B.); thletourneau@yahoo.fr (T.L.T.); jjschott@univ-nantes.fr (J.-J.S.).
authors.forename: Pauline
authors.initials: P
authors.lastname: Labbé
authors.affiliation: Institut du thorax, Inserm UMR 1087, CNRS UMR 6291, 8 Quai Moncousu, Nantes F-44007, France; damien.duval@etu.univ-nantes.fr (D.D.); pauline.labbe@etu.univ-nantes.fr (P.L.); bureau.lea@gmail.com (L.B.); thletourneau@yahoo.fr (T.L.T.); jjschott@univ-nantes.fr (J.-J.S.).
authors.forename: Léa
authors.initials: L
authors.lastname: Bureau
authors.affiliation: Institut du thorax, Inserm UMR 1087, CNRS UMR 6291, 8 Quai Moncousu, Nantes F-44007, France; damien.duval@etu.univ-nantes.fr (D.D.); pauline.labbe@etu.univ-nantes.fr (P.L.); bureau.lea@gmail.com (L.B.); thletourneau@yahoo.fr (T.L.T.); jjschott@univ-nantes.fr (J.-J.S.).
authors.forename: Thierry
authors.initials: T
authors.lastname: Le Tourneau
authors.affiliation: Department of Cell Biology and Anatomy, Medical University of South Carolina, Charleston, SC 29425, USA; norrisra@musc.edu (R.A.N.); markwald@musc.edu (R.R.M.).
authors.forename: Russell A
authors.initials: RA
authors.lastname: Norris
authors.affiliation: Department of Cell Biology and Anatomy, Medical University of South Carolina, Charleston, SC 29425, USA; norrisra@musc.edu (R.A.N.); markwald@musc.edu (R.R.M.).
authors.forename: Roger R
authors.initials: RR
authors.lastname: Markwald
authors.affiliation: Harvard Medical School, Massachusetts General Hospital, Boston, MA 02114-2696 USA; rlevine@partners.org.
authors.forename: Robert
authors.initials: R
authors.lastname: Levine
authors.affiliation: Institut du thorax, Inserm UMR 1087, CNRS UMR 6291, 8 Quai Moncousu, Nantes F-44007, France; damien.duval@etu.univ-nantes.fr (D.D.); pauline.labbe@etu.univ-nantes.fr (P.L.); bureau.lea@gmail.com (L.B.); thletourneau@yahoo.fr (T.L.T.); jjschott@univ-nantes.fr (J.-J.S.).
authors.forename: Jean-Jacques
authors.initials: JJ
authors.lastname: Schott
authors.affiliation: Institut du thorax, Inserm UMR 1087, CNRS UMR 6291, 8 Quai Moncousu, Nantes F-44007, France; damien.duval@etu.univ-nantes.fr (D.D.); pauline.labbe@etu.univ-nantes.fr (P.L.); bureau.lea@gmail.com (L.B.); thletourneau@yahoo.fr (T.L.T.); jjschott@univ-nantes.fr (J.-J.S.).
authors.forename: Jean
authors.initials: J
authors.lastname: Mérot
keywords: Filamin-A; PTPN12; Src; mitral valve prolapse; p190RhoGAP