title: Signalling pathways mediating specific synergistic interactions between GDF9 and BMP15.
abstract: Growth differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BMP15) are two proteins selectively expressed in the oocyte which are essential for normal fertility. Both of these proteins are members of the transforming growth factor beta (TGF-β) superfamily and as such are produced as pre-proproteins, existing after proteolytic processing as a complex of the respective pro and mature regions. Previous work has shown that these two proteins interact both at the genetic and cellular signalling levels. In this study, our aim was to determine if the purified mature regions of GDF9 and BMP15 exhibit synergistic interactions on granulosa cells and to determine if such interactions are specific to these two proteins. We have used primary cultures of murine granulosa cells and [(3)H]-thymidine incorporation or transcriptional reporter assays as our readouts. We observed clear synergistic interactions between the mature regions of GDF9 and BMP15 when either DNA synthesis or SMAD3 signalling were examined. GDF9/BMP15 synergistic interactions were specific such that neither factor could be replaced by an analogous TGF-β superfamily member. The GDF9/BMP15 synergistic signalling response was inhibited by the SMAD2/3 phosphorylation inhibitor SB431542, as well as inhibition of the mitogen-activated protein kinase or rous sarcoma oncogene (SRC) signalling pathways, but not the nuclear factor kappa B pathway. In this study, we show that purified mature regions of GDF9 and BMP15 synergistically interact in a specific manner which is not dependent on the presence of a pro-region. This synergistic interaction is targeted at the SMAD3 pathway, and is dependent on ERK1/2 and SRC kinase signalling.
authors.affiliation: Research Centre for Reproductive Health, Discipline of Obstetrics and Gynaecology, Robinson Institute, School of Paediatrics and Reproductive Health, University of Adelaide, Adelaide 5005, Australia. david.mottershead@adelaide.edu.au
authors.forename: David G
authors.initials: DG
authors.lastname: Mottershead
authors.forename: Lesley J
authors.initials: LJ
authors.lastname: Ritter
authors.forename: Robert B
authors.initials: RB
authors.lastname: Gilchrist
mesh_terms: D000818:Animals; D001549:Benzamides / Q000494:pharmacology; D055430:Bone Morphogenetic Protein 15 / Q000378:metabolism*; D002478:Cells, Cultured; D054885:Cumulus Cells / Q000187:drug effects / Q000378:metabolism*; D004149:Dioxoles / Q000494:pharmacology; D005260:Female; D006107:Granulosa Cells / Q000187:drug effects / Q000378:metabolism*; D055429:Growth Differentiation Factor 9 / Q000378:metabolism*; D051379:Mice; D009865:Oocytes / Q000187:drug effects / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D011485:Protein Binding / Q000187:drug effects; D015398:Signal Transduction / Q000187:drug effects; D051898:Smad1 Protein / Q000378:metabolism; D051900:Smad3 Protein / Q000378:metabolism; D051902:Smad5 Protein / Q000378:metabolism; D051904:Smad8 Protein / Q000378:metabolism
chemical_list: C459179:4-(5-benzo(1,3)dioxol-5-yl-4-pyridin-2-yl-1H-imidazol-2-yl)benzamide; D001549:Benzamides; C525902:Bmp15 protein, mouse; D055430:Bone Morphogenetic Protein 15; D004149:Dioxoles; C525898:Gdf9 protein, mouse; D055429:Growth Differentiation Factor 9; D051898:Smad1 Protein; C497401:Smad1 protein, mouse; D051900:Smad3 Protein; C497791:Smad3 protein, mouse; D051902:Smad5 Protein; C497798:Smad5 protein, mouse; D051904:Smad8 Protein; C491621:Smad9 protein, mouse