In vitro migration of Rho-deficient neutrophils is stimulus dependent. (A) Migration of WT neutrophils through Boyden chambers toward fMLF with or without Tat-C3 pretreatment (left panel) or of the indicated genotypes (right panel). (B) Migration of WT neutrophils through Boyden chambers toward CXCL1 with or without Tat-C3 pretreatment (left panel) or of the indicated genotypes (right panel). (C) Migration of neutrophils toward fMLF or CXCL1 through type 1 collagen. (D) Migration of RhoB KO² or RhoA/B dKO neutrophils toward either fMLF or CXCL1 after inhibitor pretreatment. (E) Immunoblot depicting Erk (p42/44 MAPK) phosphorylation in attached Rho-deficient neutrophils stimulated with fMLF (+/− 5 µM U0126) or CXCL1; total Erk served as the loading control. (F) Migration of neutrophils toward CXCL1 through 5-µm pore filters. Means ± SEM (n = 3): (A-C) *P < .05, **P < .01 by unpaired 2-tailed Student t test; (D) *P < .05, **P < .01, by 1-way ANOVA post hoc Dunnett’s multiple variance test.