Fig. 1. Rate of internalization of CT in HeLa K44A cells, with (
) and without (
) induction of mutant dynamin. The cells were washed, and TAG- and biotin-labeled CT (9 ng/ml) in 0.2 ml of Hepes-buffered MEM medium was added to each well containing approximately 40,000 cells. The cells were incubated at 37°C for 2-20 minutes, and bound and endocytosed CT were quantified as described in Materials and Methods, and are presented here as percent of total cell-associated toxin (mean ± s.d., n=6). The amount of total cell-associated CT at 2 and 20 minutes was 0.11 and 0.38 ng/40,000 cells, respectively. Equal amounts of CT were bound to non-induced and induced cells.
