RIPK1 and Yersinia infectious disease: IKK has been shown to phosphorylate RIPK1 both at Ser6 and Ser25 (14), and it is this latter site that has been shown to be important to prevent cell death in MEFs and during Yersinia infection (16), in which effective immune control of infection depends on RIPK1 triggered cell death processes in myeloid cells (25).