Effect of monensin on fluid phase and receptor mediated endocytosis by rat hepatocyte monolayers.
We have investigated the effect of monensin on the uptake of sucrose and sucrose-asialofetuin by rat hepatocyte monolayers and on the intracellular traffic of these molecules. Endocytosis of sucrose is not affected by monensin while that of sucrose-asialofetuin is markedly inhibited. Monensin causes a decrease of galactosyltransferase, a Golgi membrane enzyme without affecting dipeptidylpeptidase IV a plasma membrane enzyme and three lysosomal hydrolases. The inhibition of sucrose-asialofetuin uptake is proportional to the reduction of galactosyltransferase activity. Differential and isopycnic centrifugation results indicate that monensin at a concentration (10 mumol/l) that markedly decreases sucrose-asialofetuin uptake does not prevent the transfer of sucrose and sucrose-asialofetuin from endosomes to lysosomes.
Thirion
J
J
Laboratoire de Chimie Physiologique, Facultés Universitaires Notre-Dame de la Paix, Namur, Belgium.
Wattiaux
R
R
D000818:Animals; D001212:Asialoglycoproteins; D018819:Dipeptidyl Peptidase 4; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases / Q000378:metabolism; D004705:Endocytosis / Q000187:drug effects*; D060748:Fetuins; D005700:Galactosyltransferases / Q000378:metabolism; D006056:Golgi Apparatus / Q000201:enzymology; D008099:Liver / Q000166:cytology*; D008247:Lysosomes / Q000201:enzymology; D008985:Monensin / Q000494:pharmacology*; D051381:Rats; D013395:Sucrose / Q000378:metabolism; D000509:alpha-Fetoproteins / Q000378:metabolism
D001212:Asialoglycoproteins; D060748:Fetuins; D000509:alpha-Fetoproteins; C017029:asialofetuin; D013395:Sucrose; D008985:Monensin; D005700:Galactosyltransferases; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases; D018819:Dipeptidyl Peptidase 4