TNF-α was not associated with activity of Rab5 through the NF-κB pathway. (A) Ca9-22 cells were transfected with an expression vector with an inserted GFP-Rab5 gene. The transfected cells were preincubated with an NF-κB inhibitor (PDTC, 5 μM) at 37°C for 1 h and were then incubated with TNF-α for 3 h. The active form of Rab5 in the cell lysates was subjected to a GST-R5BD pull-down assay and was analyzed by Western blotting with anti-GFP antibodies as described in Methods. (B) Level of the active form of Rab5-GTP was normalized to total GFP-Rab5 and quantified by a densitometer. (means ± deviations [SD] [n = 3]).