(A–E) PC12 cells and (F–J) CHO-K1/1.5 cells were fixed 24 h after transient transfection with the indicated constructs. Each is typical of at least five independent experiments. (A, F) Wild-type β3. (B, G) The ΔECD mutant. (C, H) The ΔICD mutant. (D, I) The C96A mutant. (E, J) The C24A mutant. Wild-type β3 and ΔECD and C24A mutants exhibit some plasma-membrane staining. The ΔICD and C96A mutants failed to reach the plasma membrane and were retained inside the cell. Scale bar, 2 μm.