Structural basis for the platelet-collagen interaction: the smallest motif within collagen that recognizes and activates platelet Glycoprotein VI contains two glycine-proline-hydroxyproline triplets.
Collagen-related peptide is a selective agonist for the platelet collagen receptor Glycoprotein VI. The triple helical peptide contains ten GPO triplets/strand (single letter amino acid nomenclature, where O is hydroxyproline) and so over-represents GPO compared with native collagen sequence. To investigate the ability of Glycoprotein VI to recognize GPO triplets in a setting more representative of the collagens, we synthesized a set of triple helical peptides containing fewer GPO triplets, varying their number and spacing within an inert (GPP)n backbone. The adhesion of recombinant human Glycoprotein VI ectodo-main, like that of human platelets, to these peptides increased with their GPO content, and platelet adhesion was abolished by the specific anti-Glycoprotein VI-blocking antibody, 10B12. Platelet aggregation and protein tyrosine phosphorylation were induced only by cross-linked peptides and only those that contained two or more GPO triplets. Such peptides were less potent than cross-linked collagen-related peptide. Our data suggest that both the sequences GPOGPO and GPO.........GPO represent functional Glycoprotein VI recognition motifs within collagen. Furthermore, we propose that the (GPO)4 motif can support simultaneous binding of two glycoprotein VI molecules, in either a parallel or anti-parallel stacking arrangement, which could play an important role in activation of signaling.
Smethurst
Peter A
PA
Department of Biochemistry, University of Cambridge, Downing Site, Cambridge CB2 1QW, United Kingdom.
Onley
David J
DJ
Jarvis
Gavin E
GE
O'Connor
Marie N
MN
Knight
C Graham
CG
Herr
Andrew B
AB
Ouwehand
Willem H
WH
Farndale
Richard W
RW
D001665:Binding Sites / Q000502:physiology; D001792:Blood Platelets / Q000378:metabolism*; D003094:Collagen / Q000737:chemistry* / Q000378:metabolism*; D003432:Cross-Linking Reagents / Q000737:chemistry / Q000378:metabolism; D005998:Glycine / Q000378:metabolism; D006801:Humans; D006909:Hydroxyproline / Q000378:metabolism; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D010766:Phosphorylation; D010973:Platelet Adhesiveness / Q000502:physiology*; D010974:Platelet Aggregation / Q000502:physiology; D010980:Platelet Membrane Glycoproteins / Q000737:chemistry / Q000378:metabolism*; D011392:Proline / Q000378:metabolism; D011485:Protein Binding / Q000502:physiology; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology; D013329:Structure-Activity Relationship; D014443:Tyrosine / Q000378:metabolism
D003432:Cross-Linking Reagents; D008565:Membrane Proteins; D010446:Peptide Fragments; D010980:Platelet Membrane Glycoproteins; D011994:Recombinant Proteins; C098341:platelet membrane glycoprotein VI; D014443:Tyrosine; D003094:Collagen; D011392:Proline; D006909:Hydroxyproline; D005998:Glycine