Fig. 3.
ApoER2 and JIP4 partnership is required for aPL activation of PP2A and inhibition of trophoblast cell proliferation and migration. (A) HTR8/SVneo trophoblasts were treated with control siRNA or siRNA targeting ApoER2, treated with NHIgG or aPL, and PP2A activity was measured. N=6. (B) ApoER2fl/fl or ApoERΔTR mice were injected with NHIgG or aPL as in Fig. 1, and PP2A activity in the placenta was measured on day 15. N=15. (C) Cells were treated with NHIgG or aPL, ApoER2 was immunoprecipitated, and ApoER2, Dab2, JIP4, PP2A-Aα and L309 methylation of PP2A-C were detected. (D) Cells previously transfected with siRNA targeting ApoER2 were then transfected with vector alone (+Con) or cDNA encoding wild-type apoER2 (+WT), ApoER2 with NPVA point mutation (+NPVA) or ApoER2 with C-terminal deletion (+Δ59). ApoER2 was immunoprecipitated, and ApoER2, Dab2 and JIP4 were detected. (E) Cells were transfected with control siRNA or siRNA targeting JIP4, treated with NHIgG or aPL, and PP2A activity was measured. N=6. (F, G) Similarly transfected cells were incubated with or without 10% serum and cell proliferation (F, N=18) and cell migration were assessed (G, N=15). Values are Mean±SEM. Two-way ANOVA with Tukey’s post-hoc test (A), or aligned rank transform two-way ANOVA with Benjamini and Hochberg correction (B, E-G) was used.