Epitope mapping of a function-blocking beta 1 integrin antibody by phage display.
Integrins are a major class of cell surface receptors involved in cell-cell and cell-matrix adhesion and communication. Ha2/11 is a function-blocking anti-rat beta 1 integrin hamster IgM that should be a useful reagent for understanding beta 1 integrin function. We demonstrate that Ha2/11 cross reacts with human, Xenopus, and Drosophila beta 1 integrins, and use phage display to map the epitope for Ha2/11 to residues within the sequence LRSGEPQTF which lies 18 amino acids proximal to the putative I domain in beta 1 integrins. Monoclonal antibody mapping experiments, mutational analyses, and direct binding assays have implicated integrin I domains in both cation and ligand binding. Our data therefore suggest that Ha2/11 blocks beta 1 integrin function by interfering with I domain-mediated ligand binding.
Ryan
S T
ST
Biogen, Inc., Cambridge, MA 02142, USA.
Chi-Rosso
G
G
Bonnycastle
L L
LL
Scott
J K
JK
Koteliansky
V
V
Pollard
S
S
Gotwals
P J
PJ
D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology / Q000378:metabolism / Q000494:pharmacology*; D000937:Antigen-Antibody Reactions; D002460:Cell Line; D002645:Chickens / Q000276:immunology; D003090:Coliphages / Q000235:genetics*; D016384:Consensus Sequence; D006224:Cricetinae; D003429:Cross Reactions; D004331:Drosophila melanogaster / Q000166:cytology / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes / Q000737:chemistry* / Q000378:metabolism; D005434:Flow Cytometry; D006801:Humans; D007075:Immunoglobulin M / Q000276:immunology / Q000378:metabolism / Q000494:pharmacology*; D007163:Immunosorbent Techniques; D019012:Integrin beta1 / Q000276:immunology*; D007668:Kidney / Q000166:cytology; D008024:Ligands; D051379:Mice; D009131:Muscle, Smooth, Vascular / Q000166:cytology; D010446:Peptide Fragments / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D011485:Protein Binding; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000302:isolation & purification / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity; D014982:Xenopus laevis / Q000276:immunology
D000911:Antibodies, Monoclonal; D000939:Epitopes; D007075:Immunoglobulin M; D019012:Integrin beta1; D008024:Ligands; D010446:Peptide Fragments; D011993:Recombinant Fusion Proteins