Rapid endocytosis and recycling of wheat germ agglutinin binding sites on CHO cells: evidence for two compartments in a nondegradative pathway.

摘要: The internalization and recycling of CHO cell plasma membrane components have been quantified by using iodinated wheat germ agglutinin (WGA) as an adsorptive tracer. Most these binding sites are thought to be composed a subpopulation proteins called high-molecular-weight acidic glycoproteins (HMWAG). Greater than 90% the WGA bound on surface can removed brief treatment with N-acetylglucosamine (GlcNAc). At 37 degrees C, endocytosis that had allowed bind at 4 C is curvilinear initial rapid phase occurring t1/2 6-8 min. Within 20 min, accumulation has slowed gradually steady-state 65% cell-associated located intracellularly or resistant removal GlcNAc. These portions unaffected increasing extracellular concentration from 0.003 microM 2.8 microM. By pulse-chase experiments, observed decrease in rate shown due return WGA-HMWAG complexes surface. More 60% internalized recycled within 30 mean 17 Recycling involved least two intracellular populations where significant fraction (less 30%) lost rapidly pool. not delivered lysosome. results demonstrate magnitude continuous between endosomes fibroblasts.