125I-Mannose-BSA is taken up by macrophages by receptor-mediated pinocytosis. Previous studies indicated that uptake is rapid and proceeds linearly with time in the absence of protein synthesis suggesting that receptors are conserved and recycled. Chloroquine and NH4+ inhibit uptake of 125I-Mannose-BSA and its subsequent digestion by macrophages. Inhibition of uptake is inhibitor-concentration and time dependent. Both binding of ligand (4°) and internalization of pre-bound ligand (4°) following warm-up are unaffected by the inhibitors. However, brief incubation of cells at 37° with inhibitor in the absence of ligand results in a substantial reduction in cell surface binding sites. Our interpretation of these results is that chloroquine and NH4+ inhibit receptor recycling and thereby inhibit ligand uptake.
|Number of pages||8|
|Journal||Biochemical and Biophysical Research Communications|
|State||Published - Mar 13 1980|