title: Membrane protein GARP is a receptor for latent TGF-beta on the surface of activated human Treg.
abstract: Human Treg and Th clones secrete the latent form of TGF-beta, in which the mature TGF-beta protein is bound to the latency-associated peptide (LAP), and is thereby prevented from binding to the TGF-beta receptor. We previously showed that upon TCR stimulation, human Treg clones but not Th clones produce active TGF-beta and bear LAP on their surface. Here, we show that latent TGF-beta, i.e. both LAP and mature TGF-beta, binds to glycoprotein A repetitions predominant (GARP), a transmembrane protein containing leucine rich repeats, which is present on the surface of stimulated Treg clones but not on Th clones. Membrane localization of latent TGF-beta mediated by binding to GARP may be necessary for the ability of Treg to activate TGF-beta upon TCR stimulation. However, it is not sufficient as lentiviral-mediated expression of GARP in human Th cells induces binding of latent TGF-beta to the cell surface, but does not result in the production of active TGF-beta upon stimulation of these Th cells.
authors.affiliation: de Duve Institute, Université catholique de Louvain, Brussels, Belgium.
authors.forename: Julie
authors.initials: J
authors.lastname: Stockis
authors.forename: Didier
authors.initials: D
authors.lastname: Colau
authors.forename: Pierre G
authors.initials: PG
authors.lastname: Coulie
authors.forename: Sophie
authors.initials: S
authors.lastname: Lucas
mesh_terms: D015153:Blotting, Western; D015704:CD4 Antigens / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism*; D002478:Cells, Cultured; D005434:Flow Cytometry; D006801:Humans; D053645:Interleukin-2 Receptor alpha Subunit / Q000378:metabolism; D053699:Interleukin-7 Receptor alpha Subunit / Q000378:metabolism; D019169:Jurkat Cells; D053779:Latent TGF-beta Binding Proteins / Q000235:genetics / Q000378:metabolism; D008213:Lymphocyte Activation / Q000276:immunology; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008954:Models, Biological; D016853:Muromonab-CD3 / Q000276:immunology; D011485:Protein Binding; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D050378:T-Lymphocytes, Regulatory / Q000166:cytology / Q000276:immunology / Q000378:metabolism*; D016212:Transforming Growth Factor beta / Q000235:genetics / Q000378:metabolism*
chemical_list: D015704:CD4 Antigens; D053645:Interleukin-2 Receptor alpha Subunit; D053699:Interleukin-7 Receptor alpha Subunit; C087215:LRRC32 protein, human; D053779:Latent TGF-beta Binding Proteins; D008565:Membrane Proteins; D016853:Muromonab-CD3; D016212:Transforming Growth Factor beta