ZFP91 and hepatocellular carcinoma: Furthermore, while the wild-type hnRNP A1 vector or hnRNP A1 K8R mutant together with ZFP91 was cotransfected into HCC MHCC-LM3 cells, ZFP91 did not impair the HCC cell malignant phenotypes induced by hnRNP A1 K8R overexpression but not by wild-type hnRNP A1 overexpression because ZFP91 could ubiquitinate and degrade wild-type hnRNP A1 protein but not hnRNP A1 K8R mutant protein in which the ZFP91-regulated ubiquitination lysine site was mutated in hnRNP A1 protein (Figure 5E-5H).