Fig. 3.

ABCA1 silencing is associated with decreased activation of PI3 kinase and increased TG secretion. Control and ABCA1 siRNA transfected McA cells were incubated with 0.8 mM oleate for 24 h. A: PI3 kinase activation was determined by Western blot analysis of p-PI3 kinase p85/p55. Data represent mean ± SEM for three samples obtained in two separate experiments. B: Cells were harvested and Western blotted for ABCA1, p-PI3 kinase p85/p55, p-AKT, p-mTOR, MTP, and β-actin (loading control) as indicated. C: Control or ABCA1 siRNA transfected McA cells were incubated with vehicle (DMSO), LY294002 (10 μM), or wortmannin (100 nM) as indicated for 1 h before addition of radiolabeling medium ([³H]oleate (5 μCi/ml) + 0.8 mM oleate). After additional 12 h incubation, lipids were extracted from medium and radiolabel incorporation into TG was quantified by TLC. Data (mean ± SEM, n = 3–4) were normalized to cellular protein content. ** (P < 0.01) by Student's t-test; ns, not significant.