WNK2 and bacterial infectious disease: Similarly, the increased susceptibility of Gadd45b−/− mice to bacterial infections has been shown to involve a deregulation of the mitogen-activated protein kinase kinase kinase (MAPKKK), MAP/ERK kinase kinase 4 (MEKK4)/MAP three kinase 1 (MTK1) [36], rather than MKK7, and consequently would be unaffected by DTP3.