STX2 and digestive system infectious disorder: In order to explore the roles that ER stress and apoptosis play in cell death and kidney dysfunction in vivo, we examined expression of cellular ER stress markers, as well as anti- and pro-apoptotic markers in animal models of Stx2-induced kidney injury using either Stx2 challenge alone or Stx2 exposure from intestinal infection with toxin-producing Citrobacter rodentium [23].