title: Capns1, a new binding partner of RasGAP-SH3 domain in K-Ras(V12) oncogenic cells: modulation of cell survival and migration.
abstract: Ras GTPase-activating protein (RasGAP) is hypothesized to be an effector of oncogenic Ras stimulating numerous downstream cellular signaling cascades involved in survival, proliferation and motility. In this study, we identified calpain small subunit-1 (Capns1) as a new RasGAP-SH3 domain binding partner, using yeast two-hybrid screening. The interaction was confirmed by co-immunoprecipitation assay and was found specific to cells expressing oncogenic K-Ras. We used confocal microscopy to analyze our stably transfected cell model producing mutant Ras (PC3Ras(V12)). Staining for RasGAP-SH3/Capns1 co-localization was two-fold stronger in the protrusions of Ras(V12) cells than in PC3 cells. RasGAP or Capns1 knockdown in PC3Ras(V12) cells induced a two- to three-fold increase in apoptosis. Capns1 gene silencing reduced the speed and increased the persistence of movement in PC3Ras(V12) cells. In contrast, RasGAP knockdown in PC3Ras(V12) cells increased cell migration. Knockdown of both proteins altered the speed and directionality of cell motility. Our findings suggest that RasGAP and Capns1 interaction in oncogenic Ras cells is involved in regulating migration and cell survival.
authors.affiliation: Laboratoire de Pharmacochimie Moléculaire et Cellulaire, Université Paris Descartes, Unités de Formation et de Recherche (UFR) Biomédicale, 45 rue des Saints-Pères, 75270, Paris cedex 06, France.
authors.forename: Perayot
authors.initials: P
authors.lastname: Pamonsinlapatham
authors.forename: Brunilde
authors.initials: B
authors.lastname: Gril
authors.forename: Sylvie
authors.initials: S
authors.lastname: Dufour
authors.forename: Réda
authors.initials: R
authors.lastname: Hadj-Slimane
authors.forename: Véronique
authors.initials: V
authors.lastname: Gigoux
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Pethe
authors.forename: Sébastien
authors.initials: S
authors.lastname: L'hoste
authors.forename: Jacques
authors.initials: J
authors.lastname: Camonis
authors.forename: Christiane
authors.initials: C
authors.lastname: Garbay
authors.forename: Françoise
authors.initials: F
authors.lastname: Raynaud
authors.forename: Michel
authors.initials: M
authors.lastname: Vidal