Presence of asialoglycoprotein receptors in the Golgi complex in the absence of protein synthesis.
In rat hepatocytes the Golgi complex contains a considerable amount of receptors for asialoglycoproteins (ASGP-R). To establish whether the presence of ASGP-R in the Golgi complex originate from de novo synthesis isolated rat hepatocytes were incubated with 100 micrograms/ml cycloheximide to stop protein synthesis. Provided that protein synthesis was completely inhibited by cycloheximide, uptake and degradation of ligand (asialo-orosomucoid) were unaffected. Also intracellular transport of newly synthesized proteins, as determined by monitoring biosynthesis and intracellular transport of albumin and ASGP-R, was not affected. After culturing the cells for 3.5 h in the presence of cycloheximide, no more albumin could be detected in the Golgi complex with immunofluorescence microscopy. However, immunocytochemical assessment showed that the ASGP-R was still in the Golgi complex. These results suggest that the Golgi complex contains a pool of ASGP-R which is independent of neosynthesis for several hours.
D000418:Albumins / Q000378:metabolism; D000818:Animals; D037263:Asialoglycoprotein Receptor; D001692:Biological Transport / Q000187:drug effects; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D003513:Cycloheximide / Q000494:pharmacology; D004705:Endocytosis / Q000187:drug effects; D004721:Endoplasmic Reticulum / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D006056:Golgi Apparatus / Q000032:analysis*; D008099:Liver; D014176:Protein Biosynthesis; D051381:Rats; D011919:Rats, Inbred Strains; D011971:Receptors, Immunologic / Q000032:analysis* / Q000096:biosynthesis / Q000378:metabolism
D000418:Albumins; D037263:Asialoglycoprotein Receptor; D011971:Receptors, Immunologic; D003513:Cycloheximide