Figure 8.

STxB and BiP colocalize even after extraction with Triton X-100. Cy3-coupled STxB-Glyc-KDEL was bound to the plasma membrane of HeLa cells on ice. The cells were washed, shifted to 37°C for 4 h, placed on ice, incubated (+TX100) or not (−TX100) for 1 min in 1% Triton X-100-containing buffer, and then fixed at room temperature for 15 min. The fixed and permeabilized (saponin) cells were incubated with the indicated antibodies, mounted in Mowiol, and viewed by confocal microscopy. Note that even after extraction with Triton X-100, BiP labeling colocalized with STxB-Glyc-KDEL-specific labeling.