GPR39 and infection: In human colon epithelial cancer cells (Caco-2), through the mitogen-activated protein kinase (MAPK) and phosphatidylinositol 3-kinase (PI3K) pathways, ZnR/GPR39 activated Zn2+-dependent mTOR/p70 ribosomal S6 protein kinase (p70S6K) and protein kinase C-ζ (PKCz), enhanced cell proliferation and differentiation, and promoted the abundant expression of ZO-1, occludin and E-cadherin to attenuate the colitis and intestinal damage caused by STm infections [59, 62].