Figure 3.

Palmitoylation of apoB-29 is required for secretion of larger and lower-density lipoprotein particles. (A) ApoB-29 particles secreted from McArdle-RH7777 cells were separated on 3–10% nondenaturing gradient gel electrophoresis and analyzed by Western blot analysis. Typical gel migration patterns of WT palmitoylated apoB-29 and nonpalmitoylated Cys1085Ser apoB-29 are shown. (B) Isopycnic density gradient analyses of lipoprotein particles secreted from McArdle-RH7777 cells. Fractions collected from the bottom to the top of the gradient were numbered 1–20. Densities (grams per milliliter) of fractions 1, 5, 10, 15, and 20 are shown above the corresponding fraction numbers. Typical distributions of Cys1085Ser mutant apoB-29, WT apoB-29, and endogenous rat apoB-100 lipoproteins throughout the KBr gradient as revealed by Western blot analysis are shown. (C) Graphical representation of the average relative distribution of WT (□) and Cys1085Ser mutant (♦) apoB-29s in the KBr gradient as a function of fraction number. Relative amounts of apoB-29s were calculated as a percentage of the peak value in fractions 1–14 of each gradient. Average peak densities (grams per milliliter) of particles containing WT (n = 7) or Cys1085Ser mutant (n = 6) apoB-29s are shown above the corresponding curves.