title: Soluble CD109 binds TGF-β and antagonizes TGF-β signalling and responses.
abstract: Transforming growth factor-β (TGF-β) is a multifunctional cytokine implicated in many diseases, including tissue fibrosis and cancer. TGF-β mediates diverse biological responses by signalling through type I and II TGF-β receptors (TβRI and TβRII). We have previously identified CD109, a glycosylphosphatidylinositol (GPI)-anchored protein, as a novel TGF-β co-receptor that negatively regulates TGF-β signalling and responses and demonstrated that membrane-anchored CD109 promotes TGF-β receptor degradation via a SMAD7/Smurf2-mediated mechanism. To determine whether CD109 released from the cell surface (soluble CD109 or sCD109) also acts as a TGF-β antagonist, we determined the efficacy of recombinant sCD109 to interact with TGF-β and inhibit TGF-β signalling and responses. Our results demonstrate that sCD109 binds TGF-β with high affinity as determined by surface plasmon resonance (SPR) and cell-based radioligand binding and affinity labelling competition assays. SPR detected slow dissociation kinetics between sCD109 and TGF-β at low concentrations, indicating a stable and effective interaction. In addition, sCD109 antagonizes TGF-β-induced Smad2/3 phosphorylation, transcription and cell migration. Together, our results suggest that sCD109 can bind TGF-β, inhibit TGF-β binding to its receptors and decrease TGF-β signalling and TGF-β-induced cellular responses.
authors.affiliation: Division of Plastic Surgery, Department of Surgery, McGill University Health Centre, Montreal, QC, Canada, H3G1A4.
authors.forename: Carter
authors.initials: C
authors.lastname: Li
authors.affiliation: McGill SPR-MS Facility, McGill University, Montreal, QC, Canada, H3A 2B4.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Hancock
authors.affiliation: Division of Plastic Surgery, Department of Surgery, McGill University Health Centre, Montreal, QC, Canada, H3G1A4.
authors.forename: Priyanka
authors.initials: P
authors.lastname: Sehgal
authors.affiliation: Division of Plastic Surgery, Department of Surgery, McGill University Health Centre, Montreal, QC, Canada, H3G1A4.
authors.forename: Shufeng
authors.initials: S
authors.lastname: Zhou
authors.affiliation: Department of Anatomy and Cell Biology, Faculty of Medicine and Faculty of Dentistry, McGill University, Montreal, QC, Canada, H3A 0C7.
authors.forename: Dieter P
authors.initials: DP
authors.lastname: Reinhardt
authors.affiliation: Division of Plastic Surgery, Department of Surgery, McGill University Health Centre, Montreal, QC, Canada, H3G1A4 anie.philip@mcgill.ca.
authors.forename: Anie
authors.initials: A
authors.lastname: Philip
mesh_terms: D015703:Antigens, CD / Q000378:metabolism*; D002460:Cell Line; D002465:Cell Movement; D005353:Fibronectins / Q000378:metabolism; D058851:GPI-Linked Proteins / Q000378:metabolism; D006801:Humans; D015603:Keratinocytes / Q000378:metabolism; D009363:Neoplasm Proteins / Q000378:metabolism*; D010766:Phosphorylation; D017395:Plasminogen Activator Inhibitor 1 / Q000378:metabolism; D020033:Protein Isoforms / Q000037:antagonists & inhibitors / Q000378:metabolism; D011869:Radioligand Assay; D011994:Recombinant Proteins / Q000378:metabolism; D015398:Signal Transduction; D051900:Smad3 Protein / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic; D016212:Transforming Growth Factor beta / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D015703:Antigens, CD; C120523:CD109 protein, human; D005353:Fibronectins; D058851:GPI-Linked Proteins; D009363:Neoplasm Proteins; D017395:Plasminogen Activator Inhibitor 1; D020033:Protein Isoforms; D011994:Recombinant Proteins; C051321:SERPINE1 protein, human; C497790:SMAD3 protein, human; D051900:Smad3 Protein; D016212:Transforming Growth Factor beta
keywords: CD109; TGF-β isoforms; binding; glycoprotein; inhibitor; trap