CCN2 and acute kidney injury: Increased expression of the transcription factor krϋppel-like transcription factor4 (KLF4) promotes the expression of the E3 enzyme itchy E3 ubiquitin-protein ligase (ITCH).ITCH activates YAP by promoting the ubiquitination of the phosphatase large tumor suppressor 1 (LATS1).YAP can promote renal fibrosis after AKI by promoting the expression of transforming growth factor-β (TGF-β) and connective tissue growth factor (CTGF)28.