AC-induced STAT3 activation in DCs is MerTK dependent. MerTK^+/+ BMDCs (A-C) or MerTK^+/+ and MerTK^−/− sDCs (D) were treated with ACs for the indicated times. pSTAT3, STAT3, and β actin were measured in whole-cell lysates via Western blot using the same membranes (A,D), or DNA-binding activity of nuclear STAT3 and SP1 determined by EMSA (B) and a supershift assay (C). (E) MerTK^+/+ and MerTK^−/− sDCs were treated with Gas6 (150 nM) for the indicated times, and pSTAT3 and STAT3 were measured in whole-cell lysates via Western blot using the same membrane. (D-E) Fold induction of pSTAT3 was determined by normalizing densitometric readings against control cultures. (F) MerTK^+/+ BMDCs were incubated with ACs for the indicated times, MerTK was immunoprecipitated from whole-cell lysates, and Western blot membranes were probed for STAT3 and MerTK protein using the same membrane. Data are representative of a minimum of 3 experiments.