FIG 2.

VopQ but not VopQ^S200P induces an early activation of ERK1/2 MAPK signaling. (A) Immunoblot showing phosphorylated Erk1 and Erk2 (p-Erk1/2) and total Erk1/2 in starved mouse embryonic fibroblasts (MEFs) 45, 60, 75, and 90 min after infection with T3SS1⁺ or T3SS1⁻ V. parahaemolyticus. A pulse of p-Erk1/2 was observed early during infection with T3SS1⁺ but not T3SS1⁻ V. parahaemolyticus. (B) Immunoblot for total Egr1 in starved MEFs 45, 60, 75, and 90 min after infection with POR3:T3SS1⁺ or POR3:T3SS1⁻. A rise in Egr1 protein levels over time was observed only in T3SS1⁺-infected MEFs. (C) Immunoblot for p-Erk1/2 and total Erk1/2 in starved MEFs 45, 60, 75, and 90 min after infection with T3SS1⁺ΔvopQ or T3SS1⁺ΔvopS V. parahaemolyticus. T3SS1⁺ΔvopQ did not induce Erk1/2 phosphorylation while T3SS1⁺ΔvopS induced prolonged Erk1/2 phosphorylation. (D) Immunoblot for total Egr1 in starved MEFs 45, 60, 75, and 90 min after infection with V. parahaemolyticus T3SS1⁺ΔvopQ or T3SS1⁺ΔvopS. No rise in Egr1 protein levels was observed in T3SS1⁺ΔvopQ-infected MEFs, while T3SS1⁺ΔvopS caused an increase in Egr1 protein levels. (E) Immunoblot showing p-Erk1/2 and total Erk1/2 in starved MEFs infected with T3SS1⁺, T3SS1⁺vopQ^S200P, T3SS1⁺ΔvopQ, and T3SS1⁺ΔvopQ+pvopQ V. parahaemolyticus strains for 45, 60, 75, and 90 min. No pulse of pERK1/2 was observed in T3SS1⁺vopQ^S200P-infected MEFs. (F) Immunoblot for total Egr1 in starved MEFs infected for 45, 60, 75, and 90 min with the same V. parahaemolyticus strains as in panel E. T3SS1⁺vopQ^S200P did not trigger an increase Egr1 protein levels in infected MEFs. In panels B, D, and F, the target band is marked with a red line, and background bands are indicated with a blue star. Blots are representative of 3 independent experiments.