Codistribution of syntaxin 6 with a marker of ISGs
but not MSGs. The distribution of endogenous SgII (A and E), p18 (B and
H), and syntaxin 6 (D and G) in PC12/PC2 cells is shown by double
labeling in confocal images, with the use of the anti-SgII antibody
175, the anti-p18 antibody 6B1/3, and anti-syntaxin 6 antibodies (D,
mAb; G, polyclonal antibody), respectively. Superimposed images (C, F,
and I) demonstrate the overlapping distribution of the syntaxin 6 only
with SgII in TGN and ISGs. Full-length SgII, recognized by 175, appears
mainly in the perinuclear region containing Golgi membranes and early
ISGs (A), whereas p18 staining is found mainly distributed in maturing
ISGs and MSGs distributed throughout the cytoplasm (B). Syntaxin 6
immunostaining can be found in the Golgi apparatus (D), where it
colocalizes with SgII (E and F). In addition to the perinuclear Golgi
staining, a punctate syntaxin 6 staining appears over the entire cell
(D and G), which does not colocalize with p18 (H and I). Selected
images from three independent experiments are shown.