FIGURE 6.

Co-expression of sortilin, APLP2, or both with PCSK9 has no major effect on LDLR degradation. Huh7 cells were transfected with a total of 3 μg using 1 μg of each vector encoding for either a control protein 7B2 (−), sortilin (+), APLP2 (+), or PCSK9 (+), as indicated. After 48 h, lysates were analyzed by Western blotting for expression of the LDLR, sortilin-Myc, APLP2-V5, intracellular pro- and mature-PCSK9-V5, and β-actin. Media were analyzed for secreted endogenous and overexpressed PCSK9-V5 using a rabbit polyclonal human PCSK9 antibody. Quantification of LDLR expression was normalized against that of β-actin. These data are representative of at least 3 different experiments showing similar results.