Ask1 inhibition reduces kidney and liver fibrosis [42] Cdc42 and Rac1 mediate JNK activation in the context of polycystin overexpression in cells [12,14] and activate Mlk2 and Mlk3 [37,43,44] However, in our model, Ask1 deletion (S2A Fig) or double deletion of Mlk2 and Mlk3 (S2B Fig) did not reduce cystic burden in Pkd2 mutants. This evidence concerns the gene MAP3K5 and Hepatic fibrosis.