SUGAR RESIDUES ON THE CELL SURFACE OF THE DISSOCIATED MOUSE KIDNEY TUBULE CELLS BY MEANS OF FERRITIN-LABELED LECTINS

Abstract

Lectin-binding sites at the cell surface of mouse kidney tubules were studied using the ferritin labeling technique. Mouse kidney tissues were successfully dissociated in an enzyme solution containing collagenase and hyaluronidase. The dissociated cells were fixed, reacted with ferritin-lectin conjugates and processed for electron microscopy. Lectins used were concanavalin A (Con A), Ricinus communis agglutinin (RcA) and Bauhinia purpusea albs hemagglutinin (BpH). The ferritin particles were found at all portions of the plasma membrane exposed directly to ferritin-lectin conjugates. Ferritin-Con A particles were typically clustered and ferritin-RcA also tended to cluster. Ferritin-BpH particles were observed abundantly at the cell surface with some sporadic clustering occurring as well. Binding sites of the three lectins tested were more abundant at the apical surface when compared with the lateral and the basal portions of the plasma membrane. It is concluded that dissociated renal tubule cells still retained the carbohydrate moieties at the cell surface and that the apical plasma membranes possess more terminal oligosaccharides, presumably, of glycoprotein than the lateral and the basal plasma membranes in renal proximal tubule cells. The regional differences of glycoprotein represents the plasma membrane polarity in terms of surface specificities in these highly organized tissue cells.