title: Nodal signals via β-arrestins and RalGTPases to regulate trophoblast invasion.
abstract: Placentation is critical for establishing a healthy pregnancy. Trophoblasts mediate implantation and placentation and certain subtypes, most notably extravillous cytotrophoblast, are highly invasive. Trophoblast invasion is tightly regulated by microenvironmental cues that dictate placental morphology and depth. In choriocarcinomas, malignant trophoblast cells become hyperinvasive, breaching the myometrium and leading to major complications. Nodal, a member of the TGF-β superfamily, is expressed throughout the endometrium during the peri-implantation period and in invasive trophoblast cells. Nodal promotes the invasion of numerous types of cancer cells. However, Nodal's role in trophoblast and choriocarcinoma cell invasion is unclear. Here we show that Nodal stimulates the invasion of both the non-malignant HTR-8SV/neo trophoblast and JAR choriocarcinoma cells in a dose-dependent manner. We found that endogenous β-arrestins and Ral GTPases, key regulators of the cell cytoskeleton, are constitutively associated with Nodal receptors (ALK4 and ALK7) in trophoblast cells and that RalA is colocalized with ALK4 in endocytic vesicles. Nodal stimulates endogenous β-arrestin2 to associate with phospho-ERK1/2, and knockdown of β-arrestin or Ral proteins impairs Nodal-induced trophoblast and choriocarcinoma cell invasion. These results demonstrate, for the first time, that β-arrestins and RalGTPases are important regulators of Nodal-induced invasion.
authors.affiliation: Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON N6A 5C1, Canada; Department of Oncology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London ON N6A 5C1, Canada.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Law
authors.affiliation: Department of Oncology, The University of Alberta, Edmonton AB T6G 2E1, Canada.
authors.forename: Guihua
authors.initials: G
authors.lastname: Zhang
authors.affiliation: Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON N6A 5C1, Canada; Department of Oncology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London ON N6A 5C1, Canada.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Dragan
authors.affiliation: Department of Oncology, The University of Alberta, Edmonton AB T6G 2E1, Canada. Electronic address: postovit@ualberta.ca.
authors.forename: Lynne-Marie
authors.initials: LM
authors.lastname: Postovit
authors.affiliation: Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON N6A 5C1, Canada; Department of Oncology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London ON N6A 5C1, Canada. Electronic address: moshmi.bhattacharya@schulich.uwo.ca.
authors.forename: Moshmi
authors.initials: M
authors.lastname: Bhattacharya
mesh_terms: D030201:Activin Receptors, Type I / Q000737:chemistry / Q000378:metabolism; D019390:Arrestins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D002465:Cell Movement / Q000187:drug effects; D006801:Humans; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D055457:Nodal Protein / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D011485:Protein Binding; D034622:RNA Interference; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects; D014168:Transferrin / Q000378:metabolism; D014327:Trophoblasts / Q000166:cytology / Q000378:metabolism; D000071557:beta-Arrestins; D020725:ral GTP-Binding Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*
chemical_list: D019390:Arrestins; C526007:NODAL protein, human; D055457:Nodal Protein; C483163:Ralb protein, human; D011994:Recombinant Proteins; D014168:Transferrin; D000071557:beta-Arrestins; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; C498932:ACVR1B protein, human; C424205:ACVR1C protein, human; D030201:Activin Receptors, Type I; C492198:RALA protein, human; D020725:ral GTP-Binding Proteins
keywords: Invasion; Nodal; Placenta; Ral GTPase; Trophoblast; β-arrestins