FIGURE 6.

The effect of the AAA and DRK mutation on lipoprotein release in cellular assays. The ability of fibroblasts expressing normal LDLR (WT), LDLR-AAA (AAA), or LDLR-DRK (DRK) to internalize (A and C) and accumulate (B and D) LDL (A and B), and β-VLDL (C and D) was determined. Internalization assays determined the ratio of internal/surface ¹²⁵I-LDL (A) or ¹²⁵I-β-VLDL (C) over 15 min at 37 °C. The accumulation assays determined the amount of Alexa546-LDL (B) or DiI-β-VLDL (D) fluorescence associated with each cell type over 4 h. Data are presented as the percent of normal (WT) at 4 h. All experiments were performed in triplicate and are presented as means ± S.D.