SMAD2 and renal fibrosis: Phosphorylated Smad2/3 heteroligomerizes with Smad 4, a common partner Smad, and the complexes translocate into the nucleus to regulate the transcription of target genes.32 In a rat UUO model, TGFβ‐RII mRNA significantly increased, and inhibition of TGFβ‐RII ameliorated the progression of renal fibrosis.33 Consistent with the reported data, we also found that TGFβ‐RI and RII were highly expressed in the fibrotic kidneys.