Role of concanavalin A as an endocytic modulator in Chinese hamster ovary cells.
The effect of the lectin, concanavalin A (Con A), on pinocytic uptake and pinosome-lysosome fusion in Chinese hamster ovary (CHO) cells, a fibroblast line, was investigated. The glycosylated protein, horseradish peroxidase (HRPase), and the non-glycosylated protein, 125I-labelled bovine serum albumin ([125I]BSA), was used as endocytic tracers. Con A at high concentrations (greater than or equal to 50 micrograms/ml) promoted the uptake of HRPase and inhibited the degradation of ingested HRPase. Con A inhibited the degradation of HRPase whether the two were added simultaneously or at different times to the cultures. Fusion of HRPase-positive pinosomes with secondary lysosomes was observed by electron microscopy in Con A-treated CHO cells. Con A at 200 micrograms/ml had no effect on either the uptake or degradation of [125I]BSA. Together these observations strongly suggest that the effects of high Con A concentrations on the uptake and degradation of HRPase are a consequence of direct complex formation between lectin and glycoprotein. Con A does not appear to have a general modulating effect on the dynamics of endocytic membrane in CHO cells.
D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002459:Cell Fusion / Q000187:drug effects; D002460:Cell Line; D003208:Concanavalin A / Q000494:pharmacology*; D006224:Cricetinae; D003412:Cricetulus; D005260:Female; D005347:Fibroblasts / Q000502:physiology; D006735:Horseradish Peroxidase / Q000378:metabolism; D007700:Kinetics; D008247:Lysosomes / Q000502:physiology; D010053:Ovary / Q000166:cytology; D010873:Pinocytosis / Q000187:drug effects*; D012710:Serum Albumin, Bovine / Q000378:metabolism
D003208:Concanavalin A; D012710:Serum Albumin, Bovine; D006735:Horseradish Peroxidase