Demonstration of high affinity fibronectin receptors on rat hepatocytes in suspension.
A cell-binding peptide (Mr = 85,000) which lacks the gelatin- and heparin-binding domains, was purified from trypsin-digested fibronectin. Preincubation of rat hepatocytes in suspension with the peptide, inhibited initial attachment of the cells to immobilized fibronectin while attachment to immobilized laminin and collagen was unaffected. 125I-labeled 85-kDa peptide bound to the cells in suspension at 4 degrees C in a time-dependent, saturable, and partially reversible reaction. Scatchard analysis of the binding data indicated a single class of receptors with a Kd of 1.7 X 10(-8) M. The number of binding-sites was approximately 2.8 X 10(5)/cell. Unlabeled 85-kDa peptide inhibited the binding of 125I-labeled 85-kDa peptide 30-fold more effectively than intact fibronectin. These results provide direct evidence for the presence of a domain in the fibronectin molecule which has or may acquire a high affinity for receptors involved in adhesion of hepatocytes to immobilized fibronectin.
Johansson
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D000818:Animals; D005353:Fibronectins / Q000378:metabolism*; D007700:Kinetics; D008099:Liver / Q000378:metabolism*; D008297:Male; D010446:Peptide Fragments / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D017469:Receptors, Fibronectin; D011971:Receptors, Immunologic / Q000378:metabolism*; D014357:Trypsin / Q000378:metabolism
D005353:Fibronectins; D010446:Peptide Fragments; D017469:Receptors, Fibronectin; D011971:Receptors, Immunologic; D014357:Trypsin