Fig. 5. LOX-1-dependent OxLDL endocytosis is inhibited by potassium depletion. (A) HeLa cells were incubated with rhodamine-conjugated transferrin (red) for 15 minutes under control conditions or in potassium-free or hypertonic buffers as described in Materials and Methods. The plasma membrane was labelled with FITC-conjugated Con A (green) immediately before fixation. (B) LOX-1 expressing HeLa cells were pulsed with labelled OxLDL (red) for 5 minutes and chased at 37°C (for 55 minutes) in control, potassium-free or hypertonic buffers before labelling the plasma membrane with FITC-conjugated Con A (green) and fixation. (C) Addition of exogenous 10 mM KCl or addition of normal media for 1 hour reverses the inhibitory effects (washout) on labelled OxLDL uptake. Scale bars: 10 µm. Asterisks indicate cell nuclei. (D) The amount of internalised OxLDL under these conditions was again calculated as described in Materials and Methods (n=3 separate experiments in each of which five cells were quantified, values are mean ± s.e.m.). Comparison with control to calculate P values, ^*P<0.05.