Fig. 9. The activation and endosomal localization of Rab21 depends on the endogenous Varp protein. (A) HeLa cells were transfected with a Varp-siRNA- or control siRNA-expressing construct and the cell lysates were analyzed by western blotting with anti-Varp and anti-Hsp70 antibodies 72 hours post transfection. (B) HeLa cells were transfected with (a-f) indicated siRNA- and EGFP-Rab21 WT-expressing plasmids for 72 hours, and were fixed and labeled with an anti-EEA1 antibody (red). (g-i) HeLa cells expressing EGFP-Rab21 T33N were labeled with an anti-EEA1 antibody. Bars, 10 µm.