Internalization of PAs requires cholesterol and is not inhibited by chlorpromazine or amiloride.

<p>(A) PPC-1 cell association of PA <b>2</b> and PA <b>4</b> in presence of MβCD (cholesterol depletion agent) was reduced compared to controls Amiloride did not affect cell-association or internalization of PAs, whereas a low (10%) inhibition of cell-association was noted for PA <b>2</b> in presence of chlorpromazine. Average values and SEM are presented. (B) Qualitatively, the ratio of PAs localized on the plasma mebrane to the PAs found in intracellular vesicles was higher in MβCD treated-cells indicating that internalization was impaired. PA <b>2</b> associated with PPC-1 plasma membrane at 4°C but was not internalized after 1 hour. Scale bars: 20 µm.