Micro-heterogenous expression of peanut agglutinin-binding sites in the extracellular matrix of cultured cells.
Using double-label techniques with fluorochrome-conjugated peanut agglutinin (PNA) and indirect immunofluorescence with rabbit species-specific anti-fibronectin antibodies and a mouse monoclonal anti-fibronectin, the extracellular matrix (ECM) of cultured human and mouse fibroblasts (Hell7 and 3T3K) and human bladder epithelial cells (T24) was studied. The antibodies and PNA co-localized extensively. However, a small but consistent degree of micro-heterogeneity was revealed insofar as both PNA-positive fibronectin-negative fibrils as well as PNA-negative fibronectin-positive fibrils were observed. Fibronectin production by T24 cells (but not fibroblasts) was influenced by the growth medium, but this did not affect the heterogeneity. Trypsin removed most cell-surface fibronectin and all PNA-binding sites, but did not account for the observed phenomenon. Intracellular fibronectin, whether present naturally or induced to accumulate by culture in presence of Monensin, was PNA-negative. These data suggest that PNA-binding sites appear on fibronectin as a consequence of incorporation into the extracellular matrix, and that the resultant heterogeneity of spatial expression of beta-galactose-like residues may offer a mechanism whereby mesenchymal cells could modulate the behaviour of overlying cell-types.
D000818:Animals; D010367:Arachis; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism / Q000648:ultrastructure; D002478:Cells, Cultured; D016650:Fluorescein-5-isothiocyanate; D005452:Fluoresceins; D005455:Fluorescent Antibody Technique; D005456:Fluorescent Dyes; D006801:Humans; D007700:Kinetics; D037102:Lectins; D008168:Lung; D051379:Mice; D019887:Peanut Agglutinin; D037121:Plant Lectins; D011975:Receptors, Mitogen / Q000378:metabolism*; D013861:Thiocyanates; D001749:Urinary Bladder Neoplasms
D005452:Fluoresceins; D005456:Fluorescent Dyes; D037102:Lectins; D019887:Peanut Agglutinin; D037121:Plant Lectins; D011975:Receptors, Mitogen; D013861:Thiocyanates; C038223:peanut agglutinin receptor; D016650:Fluorescein-5-isothiocyanate