NFKB1 and plague: This is especially relevant concerning the proposed function of YopK as a regulator of translocation of effector Yops, a model that predicts increased injection of at least 3 immunomodulators: YopJ, YopH and YopM by yopK mutant Yersinia. Although YopJ has well-characterized activity in the prevention of NF-κB activation, suppression of TNF-α secretion and induction of apoptosis in vitro and in vivo, yopJ mutant Y. pestis exhibited little to no virulence defects in rodent models of plague.