Inhibition of fibronectin receptor function by antibodies against baby hamster kidney cell wheat germ agglutinin receptors.

Abstract

Previous studies suggest that the baby hamster kidney (BHK) cell fibronectin receptor is also a wheat germ agglutinin receptor (WGA-R). To analyze this possibility further, IgG and Fab fragments of antibodies produced against a BHK cell WGA-R preparation were tested to determine their effects on cell adhesion mediated by fibronectin, wheat germ agglutinin, concanavalin A, and polycationic ferritin. The WGA-R preparation was isolated by octylglucoside extraction of BHK cells followed by chromatography of the extract on WGAagarose. The antibodies against the WGA-R preparation reacted primarily wih polypeptides of molecular weights 48, 61, 83, 105, 120, 165,210, and 230 kilodaltons (kdaltons). tt was concluded that the antibodies interfered with BHK cell fibronectin receptors on the basis of the ability of anti-WGA-R IgG or Fab fragments to (a) inhibit cell spreading on fibronectin-coated substrata; (b) cause rounding and detachment of cells previously spread on fibronectin-coated substrata; and (c) inhibit binding of fibronectin-coated latex beads to the cells. Antibody activity was blocked by treatment of anti-WGA-R with the WGA-R preparation or by absorption of anti-WGA-R with intact BHK cells. The antibodies also appeared to prevent coupling of ligandreceptor complexes (involving concanavalin A or polycationic ferritin) with the cytoskeleton. Finally, cell rounding and detachment caused by the antibodies were found to require metabolic energy since it did not occur in the presence of azide or at 4°C.

Signal transduction and cytoskeletal reorganization are required for cell detachment from cell culture surfaces grafted with a temperature-responsive polymer

“…When BHK cells were treated at 4°C with antibodies against membrane proteins that also bind wheat germ aggluthinin lectin, no rounding of the cells occurred. 36 Then, when these cells were washed and incubated at 37°C, cell rounding was observed. If sodium azide was included in the incubation, the ability of the antibodies to induce cell rounding was markedly decreased.…”

Two distinct mechanisms for the interaction of cells with fibronectin substrata

“…0.01 186 k 35.1 6.0 f 1.2 strongly promotes cell adhesion but which lacks GAG binding ability (Piersbacher et al, 1983). This domain presumably interacts with a cell surface "receptor" for Fn and evidence is mounting that this "Fn receptor" is likely to be a glycoprotein (Tarone et al, 1982;Oppenheimer-Marks and Grinnell, 1982;Damsky et al, 1982;Schwarz and Juliano, 1984a).…”

“…Our results furthermore suggest that Fn may have two distinct mechanisms for interaction with cell surfaces. One of these seems to involve heparan sulfate proteoglycans and is sensitive to inhibition with heparin, while the other is insensitive to heparin and presumably involves a protein receptor for fibronectin (Oppenheimer-Marks and Grinnell, 1982;Schwarz and Juliano, 1984a).…”

Inhibitory Effect of Wheat Germ Agglutinin on Mouse Mast Cell Adhesion to Fibronectin

“…All integrins are glycoproteins [reviewed in ref. 26], and integrin FN receptor is recognized by WGA in vitro [14, 15, 27]. Although integrin-mediated adhesion to FN is based on interaction of the specific amino acid residues on α- and β-subunits with amino acid motifs on FN, the strength of binding may be modulated by various factors including glycosylation of integrin receptor [28, 29, 30].…”