ApoB/LDL effects on PCSK9 internalization and function.

Abstract

<p>(A and B) PCSK9-488 internalization in the presence of J16 (top row), LDL and J16 (middle row), or LDL+5F6+J16 (bottom row) in APLP2 siRNA treated cells. Dotted line indicates background signal, as measured by IC alone. Scale bars, 10 μM. (B) Quantification of (A) shown as average+SEM of J16 fluorescent signal per cell in APLP2 siRNA treated cells from 3 independent experiments. Dotted line indicates average IC background levels. Scale bars, 10 μM. (C) Representative western blot showing APLP2, LDLR, ApoB, Transferrin receptor (TFNR) levels in input fraction (I), IC or J16 immunoprecipitated samples (IP Ab.) under pH 7.4 or pH 6.0 conditions with increasing concentrations of ApoB, as indicated. (D) Western blot showing recombinant ApoB, LDLR-ECD, or PCSK9 in anti-LDLR immunoprecipitated samples at pH 6.0, with or without 5F6 Fab, as indicated. All experiments were performed independently at least 3 times and representative data are shown here.</p