TGFB1 and renal fibrosis: Given that TGF-β1 treatment increased TAZ protein levels, but not YAP1 protein levels (Fig. 4a,b), and that Sav1 depletion activated YAP1/TAZ target gene transcription (Fig. 4c), we examined TAZ mRNA expression in kidney tissues and assessed the functional role of TAZ in renal fibrosis.