title: Nodal·Gdf1 heterodimers with bound prodomains enable serum-independent nodal signaling and endoderm differentiation.
abstract: The TGFβ family member Nodal is central to control pluripotent stem cell fate, but its use as a stem cell differentiation factor is limited by low specific activity. During development, Nodal depends on growth and differentiation factor (Gdf)-1 and on the shared co-receptor Cryptic to specify visceral left-right axis asymmetry. We therefore asked whether the functionality of Nodal can be augmented by Gdf1. Because Nodal and Gdf1 coimmunoprecipitate each other, they were predicted to form heterodimers, possibly to facilitate diffusion or to increase the affinity for signaling receptors. Here, we report that Gdf1 suppresses an unexpected dependence of Nodal on serum proteins and that it is critically required for non-autonomous signaling in cells expressing Cryptic. Nodal, Gdf1, and their cleaved propeptides copurified as a heterodimeric low molecular weight complex that stimulated Activin receptor (Acvr) signaling far more potently than Nodal alone. Although heterodimerization with Gdf1 did not increase binding of Nodal to Fc fusions of co-receptors or Acvr extracellular domains, it was essential for soluble Acvr2 to inhibit Nodal signaling. This implies that Gdf1 potentiates Nodal activity by stabilizing a low molecular weight fraction that is susceptible to neutralization by soluble Acvr2. Finally, in differentiating human ES cells, endodermal markers were more efficiently induced by Nodal·Gdf1 than by Nodal, suggesting that Nodal·Gdf1 is an attractive new reagent to direct stem cell differentiation.
authors.affiliation: From the Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences (SV), Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland and.
authors.forename: Christophe
authors.initials: C
authors.lastname: Fuerer
authors.affiliation: McEwen Centre for Regenerative Medicine, University Health Network, Toronto, Ontario M5G 1L7, Canada.
authors.forename: M Cristina
authors.initials: MC
authors.lastname: Nostro
authors.affiliation: From the Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences (SV), Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland and Daniel.Constam@epfl.ch.
authors.forename: Daniel B
authors.initials: DB
authors.lastname: Constam
mesh_terms: D030301:Activin Receptors, Type II / Q000235:genetics / Q000378:metabolism; D000818:Animals; D002454:Cell Differentiation / Q000502:physiology*; D004622:Embryo, Mammalian / Q000166:cytology / Q000378:metabolism*; D053595:Embryonic Stem Cells / Q000166:cytology / Q000378:metabolism*; D004707:Endoderm / Q000166:cytology / Q000378:metabolism*; D055452:Growth Differentiation Factor 1 / Q000235:genetics / Q000378:metabolism*; D057809:HEK293 Cells; D056945:Hep G2 Cells; D006801:Humans; D051379:Mice; D018345:Mice, Knockout; D055457:Nodal Protein / Q000235:genetics / Q000378:metabolism*; D055503:Protein Multimerization / Q000502:physiology*; D017434:Protein Structure, Tertiary; D015398:Signal Transduction / Q000502:physiology*
chemical_list: C525977:GDF1 protein, human; C525978:Gdf1 protein, mouse; D055452:Growth Differentiation Factor 1; C526007:NODAL protein, human; D055457:Nodal Protein; C526008:Nodal protein, mouse; D030301:Activin Receptors, Type II
keywords: Embryonic Stem Cell; Growth and Differentiation Factor 1 (GDF1); Nodal; Prodomains; Proprotein Convertase; Protein Purification; Serum; Signaling; Stem Cell Differentiation; Transforming Growth Factor β (TGFβ)