title: Prolyl hydroxylation of collagen type I is required for efficient binding to integrin alpha 1 beta 1 and platelet glycoprotein VI but not to alpha 2 beta 1.
abstract: Collagen is a potent adhesive substrate for cells, an event essentially mediated by the integrins alpha 1 beta 1 and alpha 2 beta 1. Collagen fibrils also bind to the integrin alpha 2 beta 1 and the platelet receptor glycoprotein VI to activate and aggregate platelets. The distinct triple helical recognition motifs for these receptors, GXOGER and (GPO)n, respectively, all contain hydroxyproline. Using unhydroxylated collagen I produced in transgenic plants, we investigated the role of hydroxyproline in the receptor-binding properties of collagen. We show that alpha 2 beta 1 but not alpha 1 beta 1 mediates cell adhesion to unhydroxylated collagen. Soluble recombinant alpha 1 beta 1 binding to unhydroxylated collagen is considerably reduced compared with bovine collagens, but binding can be restored by prolyl hydroxylation of recombinant collagen. We also show that platelets use alpha 2 beta 1 to adhere to the unhydroxylated recombinant molecules, but the adhesion is weaker than on fully hydroxylated collagen, and the unhydroxylated collagen fibrils fail to aggregate platelets. Prolyl hydroxylation is thus required for binding of collagen to platelet glycoprotein VI and to cells by alpha 1 beta 1. These observations give new insights into the molecular basis of collagen-receptor interactions and offer new selective applications for the recombinant unhydroxylated collagen I.
authors.affiliation: Institut de Biologie et Chimie des Protéines, CNRS UMR 5086, IFR128 BioSciences Lyon-Gerland, 7 Passage du Vercors, 69367 Lyon, Cedex 7, France.
authors.forename: Stéephanie
authors.initials: S
authors.lastname: Perret
authors.forename: Johannes A
authors.initials: JA
authors.lastname: Eble
authors.forename: Pia R-M
authors.initials: PR
authors.lastname: Siljander
authors.forename: Christine
authors.initials: C
authors.lastname: Merle
authors.forename: Richard W
authors.initials: RW
authors.lastname: Farndale
authors.forename: Manfred
authors.initials: M
authors.lastname: Theisen
authors.forename: Florence
authors.initials: F
authors.lastname: Ruggiero
mesh_terms: D020816:Amino Acid Motifs; D000818:Animals; D000911:Antibodies, Monoclonal; D001792:Blood Platelets / Q000378:metabolism; D002417:Cattle; D002448:Cell Adhesion; D002460:Cell Line; D003094:Collagen / Q000737:chemistry / Q000378:metabolism; D024042:Collagen Type I / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D006801:Humans; D006900:Hydroxylation; D006909:Hydroxyproline / Q000737:chemistry; D039222:Integrin alpha1beta1 / Q000737:chemistry* / Q000378:metabolism; D008854:Microscopy, Electron; D008954:Models, Biological; D010455:Peptides / Q000737:chemistry; D030821:Plants, Genetically Modified; D010974:Platelet Aggregation; D010980:Platelet Membrane Glycoproteins / Q000737:chemistry* / Q000378:metabolism; D011392:Proline / Q000737:chemistry*; D011485:Protein Binding; D051381:Rats; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D014407:Tumor Cells, Cultured
chemical_list: D000911:Antibodies, Monoclonal; D024042:Collagen Type I; D039222:Integrin alpha1beta1; D010455:Peptides; D010980:Platelet Membrane Glycoproteins; D011994:Recombinant Proteins; C098341:platelet membrane glycoprotein VI; D003094:Collagen; D011392:Proline; D006909:Hydroxyproline