RAC1 and hepatocellular carcinoma: Altogether, in this study we demonstrated that MG53 exerted its anti-tumor effect by ubiquitination mediated degradation of RAC1 atLys5 residue and further inhibiting the RAC1-MAPK signaling pathway in HCC, which finally reversed the malignant behaviors of HCC cells and enhanced the chemosensitivity of HCC cells to sorafenib treatment (Fig. 6K).