A lipid raft-associated 67 kDa laminin receptor mediates suppressive effect of epigallocatechin-3-O-gallate on FcεRI expression

(-)-Epigallocatechin-3-O-gallate (EGCG), a major green tea polyphenol, has previously exhibited a suppressive effect on the expression of the high-affinity IgE receptor (Fc epsilon RI). This effect has been shown to be elicited by interaction with the plasma membrane microdomain lipid rafts. Recently, we have identified the 67 kDa laminin receptor (67LR) as a cell surface EGCG receptor that mediates an anti-cancer action. Here we show that the 67LR is highly associated with lipid rafts on human basophilic KU812 cells. Experiments using 67LR-enhanced and -reduced cells revealed that the EGCG's ability to downregulate Fc epsilon RI expression correlated with the amount of 67LR. Thus, these results suggest that the lipid raft-associated 67LR plays an important role in mediating the Fc epsilon RI-suppressive action of EGCG. (c) 2005 Elsevier Inc. All rights reserved.