Differential rates of glycoprotein secretion by isolated rat hepatocytes studied in terms of concanavalin A binding.
Using a concanavalin-A-based method which respects cell function, we have shown that the kinetics of glycoprotein secretion appear to depend on the nature of the oligosaccharide moiety. In 37 degrees C pulse/chase experiments using freshly isolated normal rat hepatocytes, we found that except for transferrin, whose rate of secretion was independent of its concanavalin A reactivity, the secretion of the concanavalin-A-retained forms of alpha 1 acid glycoprotein, T-kininogen, alpha 1 protease inhibitor and alpha 1 inhibitor III was slower than that of the concanavalin-A-non-retained forms. When hepatocytes were incubated at 20 degrees C, secretion was blocked with the accumulation of mainly endoglycosidase-H-sensitive forms. The secretion kinetics of the concanavalin-A-differentiated forms were still different when the temperature was shifted back to 37 degrees C. The divergence between the secretion rates of the concanavalin-A-differentiated forms would appear to be due to a late event in intracellular protein trafficking, which may depend on the sugar content and/or the number of carbohydrate chains of the glycoproteins.
Poüs
C
C
Laboratoire de biochimie générale, UFR des sciences Pharmaceutiques et Biologiques, Châtenay-Malabry, France.
Drechou
A
A
Rouzeau
J D
JD
Guibourdenche
J
J
el Moujahed
A
A
Durand
G
G
D000209:Acute-Phase Proteins; D000818:Animals; D002853:Chromatography, Liquid; D003208:Concanavalin A / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D006023:Glycoproteins / Q000378:metabolism*; D006026:Glycoside Hydrolases / Q000378:metabolism; D006596:Hexosaminidases / Q000378:metabolism; D007700:Kinetics; D007704:Kininogens / Q000378:metabolism; D008099:Liver / Q000166:cytology / Q000378:metabolism*; D008297:Male; D009961:Orosomucoid / Q000378:metabolism; D011233:Precipitin Tests; D011480:Protease Inhibitors / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D000515:alpha 1-Antitrypsin / Q000378:metabolism
D000209:Acute-Phase Proteins; D006023:Glycoproteins; D007704:Kininogens; D009961:Orosomucoid; D011480:Protease Inhibitors; D000515:alpha 1-Antitrypsin; C017894:alpha 1-inhibitor 3; D003208:Concanavalin A; D006026:Glycoside Hydrolases; D006596:Hexosaminidases