Members of the β1 integrin subfamily recognize multiple ligands such as fibronectin, laminin, and collagen and mediate cell-cell and cell-extracellular matrix interactions, β1 subunit may play a central role in regulating β1 integrin avidity. Here we have identified a small region of β1 subunit (residues 207-218) that is critical for the binding of both activating (8A2, A1A5, and TS2/16) and inhibiting (4B4, 4B5, 13, AIIB2, and P4C10) monoclonal antibodies against human β1 using interspecies chimeric β1 and site-directed mutagenesis. Chicken β1 that has human sequence within residues 207-218 (CH mutant) is recognized by all the human specific antibodies listed above. The region 207-218 is located between the two putative ligand binding sites (residues 120-182 and 220-231), and the amino acid sequence of the region involves a predicted bend structure. The other anti-β1 antibodies that do not affect cell . attachment to ligands (K20, 102DF5, LM442, and LM534) recognized the carboxyl-terminal regions of extracellular domain of β1 (residues 426-587 for K20 and 588-708 for 102DF5, LM442, and LM534, respectively). Our data suggest a potential mechanism for the avidity regulation of β1 integrin through conformational changes of β1 subunit.
|Number of pages||5|
|Journal||Journal of Biological Chemistry|
|Publication status||Published - Aug 15 1993|
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