SptP, a Salmonella typhimurium type III-secreted protein, inhibits the mitogen-activated protein kinase pathway by inhibiting Raf activation.

Salmonella has developed ways to modulate host cellular response in order to survive. Although the steps required for such modulation have been incompletely characterized, there is increasing evidence for a role for SptP, a type III secretion protein. In part, the actions of SptP are thought to be mediated through its reported inhibition of the extracellular-regulated kinase (ERK) MAP kinase pathway.