Fig. 5. Localization of Golgi stack residents in cells overexpressing C312. HeLa cells transiently transfected with C312 were analyzed by IFM using antibodies to the HA-epitope (to detect C312) and to endogenous Golgi markers as indicated. (Aa-h) Cells overexpressing C312 and co-stained for giantin, mannosidase II (ManII), GM130 or p115. Examples are representative of all cells examined. (B) Cells co-stained for galactosyltransferase (GalT; a-f) or Rab6 (g-l). In approximately 46% of analyzed C312-overexpressing cells (n=369 over 3 experiments), the GalT staining pattern was similar to untransfected cells in the same field (a,b) and to cells transfected with C312(Y2187A) (e,f), whereas in the other 54%, GalT staining was diffuse (c,d). A similar disparity was seen for Rab6; in approximately 74% of analyzed C312-overexpressing cells (n=175 over 2 representative experiments), Rab6 staining was similar to controls (g,h compared with k,l) and in 26%, Rab6 staining was diffuse (i,j).