Figure 8.

Repletion with raft-altering sterols affects Fcγ receptor–mediated signaling.A, macrophages were mock treated (control) or pretreated with 10 mM methyl-beta-cyclodextrin (MβCD) to deplete cholesterol and then washed and incubated with 2.5 mM MβCD loaded with 0.2 mM of indicated sterol. Cells were then stimulated with bovine serum albumin (BSA)–IgG immune complex (IC) for 5 min. Fc receptor γ chain (FcRγ) was immunoprecipitated (IP) and evaluated for phosphorylation of the tyrosine residue. IP samples were probed for FcRγ or phosphotyrosine (p-Tyr). Representative immunoblots are shown. B, immunoblots were quantified using ImageJ software; p-Tyr was normalized by FcRγ (n = 3). Error bars represent the SEM, and statistical significance was determined using one-way ANOVA with Tukey's multiple comparisons test. ∗p < 0.05, ∗∗p < 0.01, compared with the untreated control. ^#p < 0.05, ^##p < 0.01 compared with 0.2 mM coprostanol. All p values were adjusted for multiplicity.