title: ADP-ribosylation of Rho enhances adhesion of U937 cells to fibronectin via the alpha 5 beta 1 integrin receptor.
abstract: To examine the role of Rho GTP binding proteins in the adhesion of monocytic cells to fibronectin we used the C3 exoenzyme of Clostridium botulinum which ADP-ribosylates and inactivates Rho proteins in situ. Treatment of human monocytic U937 cells with C3 exoenzyme (10 micrograms/ml, 24 h) increased adhesion to fibronectin 2-fold but had no effect on adhesion to collagen or huamn serum albumin. The increase in fibronectin adhesion was prevented by antibodies against the alpha 5 and beta 1 integrin subunits, but surface expression of beta 1 and alpha 5 was not altered. These results suggest that Rho proteins regulate the interaction of the monocyte alpha 5 beta 1 integrin receptor with fibronectin by post receptor mechanisms.
authors.affiliation: Institut für Prophylaxe und Epidemiologie der Kreislaufkrankheiten, Ludwig-Maximilians Universität München, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Aepfelbacher
mesh_terms: D036002:ADP Ribose Transferases / Q000378:metabolism; D000244:Adenosine Diphosphate / Q000378:metabolism; D000246:Adenosine Diphosphate Ribose / Q000378:metabolism*; D001905:Botulinum Toxins; D002448:Cell Adhesion; D002460:Cell Line; D005353:Fibronectins / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000378:metabolism*; D020690:GTPase-Activating Proteins; D006801:Humans; D016023:Integrins / Q000378:metabolism*; D009243:NAD / Q000378:metabolism; D017469:Receptors, Fibronectin
chemical_list: D005353:Fibronectins; D020690:GTPase-Activating Proteins; D016023:Integrins; D017469:Receptors, Fibronectin; C085379:rho GTPase-activating protein; D009243:NAD; D000246:Adenosine Diphosphate Ribose; D000244:Adenosine Diphosphate; D036002:ADP Ribose Transferases; C063007:exoenzyme C3, Clostridium botulinum; D001905:Botulinum Toxins; D019204:GTP-Binding Proteins