TGFB1 and polycystic kidney disease: In mouse models of polycystic kidney disease pERK1/2 has been shown to improve kidney function and inhibit cell proliferation [28, 29] and in a model of chronic allograft nephropathy the effects of CI-1040 on attenuating fibrosis appeared to be mediated by a reduction in TGF-β1 biosynthesis in the allograft [22].