Fig. 8.

Effect of ubiquitin mutant Ub-K48R on PMA-regulated OAT1 internalization. (A) COS-7 cells were transfected with OAT1 (1 μg) and Ub-K48R (4 μg) (or vector as control). OAT1 internalization (15 minutes) was then determined as described under Materials and Methods, followed by immunoblotting using anti-myc antibody. (B) densitometry plot of results from (A) as well as from other experiments. The internalized surface OAT1 in PMA-treated cells was expressed as the percentage of internalized surface OAT1 in control cells. The values are mean ± S.E. (n = 3).