FIG 2.

USP13 cooperates with USP20 to regulate ERK3 protein expression. HeLa cells were transfected with the indicated SMARTpool siRNAs. After 48 h, cells were exposed to pH 6.4 acidic medium for 3 h, and lysates were analyzed by immunoblotting with anti-ERK3 antibody. (Top) Representative immunoblot; (bottom) quantification of ERK3 levels performed in three independent experiments. Results are expressed as means ± standard deviations. Statistical significance was determined by one-way analysis of variance with a Bonferroni posttest. ***, P < 0.001; **, P < 0.01; *, P < 0.05; n.s., not significant.