SKP2 and Hepatic fibrosis: Other E3 ligases that are moderately increased upon CCl4-induced liver fibrosis include Rnf4 (ring finger protein 4), Skp2 (S-phase kinase-associated protein 2), Ttc3 (tetratricopeptide repeat domain 3), and Tnfaip3 (tumor necrosis factor alpha-induced protein 3) (Figure 3c).