The collagen-binding A-domains of integrins alpha(1)beta(1) and alpha(2)beta(1) recognize the same specific amino acid sequence, GFOGER, in native (triple-helical) collagens.
We have previously assigned an integrin alpha(2)beta(1)-recognition site in collagen I to the sequence, GFOGERGVEGPOGPA (O = Hyp), corresponding to residues 502-516 of the alpha(1)(I) chain and located in the fragment alpha(1)(I)CB3 (Knight, C. G., Morton, L. F., Onley, D. J., Peachey, A. R., Messent, A. J., Smethurst, P. A., Tuckwell, D. S., Farndale, R. W., and Barnes, M. J. (1998) J. Biol. Chem. 273, 33287-33294). In this study, we show that recognition is entirely contained within the six-residue sequence GFOGER. This sequence, when in triple-helical conformation, readily supports alpha(2)beta(1)-dependent cell adhesion and exhibits divalent cation-dependent binding of isolated alpha(2)beta(1) and recombinant alpha(2) A-domain, being at least as active as the parent collagen. Replacement of E by D causes loss of recognition. The same sequence binds integrin alpha(1) A-domain and supports integrin alpha(1)beta(1)-mediated cell adhesion. Triple-helical GFOGER completely inhibits alpha(2) A-domain binding to collagens I and IV and alpha(2)beta(1)-dependent adhesion of platelets and HT 1080 cells to these collagens. It also fully inhibits alpha(1) A-domain binding to collagen I and strongly inhibits alpha(1)beta(1)-mediated adhesion of Rugli cells to this collagen but has little effect on either alpha1 A-domain binding or adhesion of Rugli cells to collagen IV. We conclude that the sequence GFOGER represents a high-affinity binding site in collagens I and IV for alpha(2)beta(1) and in collagen I for alpha(1)beta(1). Other high-affinity sites in collagen IV mediate its recognition of alpha(1)beta(1).
Knight
C G
CG
Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, United Kingdom.
Morton
L F
LF
Peachey
A R
AR
Tuckwell
D S
DS
Farndale
R W
RW
Barnes
M J
MJ
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002448:Cell Adhesion / Q000502:physiology*; D002474:Cell-Free System; D003094:Collagen / Q000737:chemistry / Q000378:metabolism*; D003488:Cyanogen Bromide; D003838:Deoxyadenine Nucleotides / Q000494:pharmacology; D006801:Humans; D039222:Integrin alpha1beta1; D016023:Integrins / Q000378:metabolism*; D008969:Molecular Sequence Data; D010446:Peptide Fragments; D011485:Protein Binding; D051381:Rats; D038981:Receptors, Collagen; D013329:Structure-Activity Relationship; D014407:Tumor Cells, Cultured
D003838:Deoxyadenine Nucleotides; D039222:Integrin alpha1beta1; D016023:Integrins; D010446:Peptide Fragments; D038981:Receptors, Collagen; D003094:Collagen; D003488:Cyanogen Bromide