MAPK3 and cyst: Furthermore, Weng Lin et al. [46] enlightened the controversial role of cAMP-PKA pathway in MDCK-cell and embryonic kidney-cyst models, where cAMP-PKA showed to exert a protective role by inhibiting TGF-β1-induced ERK1/2 phosphorylation, whereas it exacerbates the fibrotic process in cells not stimulated by TGF-β1.