OTUB1 and nonpapillary renal cell carcinoma: Treating ccRCC cells with MG132 to inhibit SIRT3 ubiquitination, we found that knocking down NUDT1 can significantly reduce the expression of OTUB1 that binds to SIRT3, which indicates that OTUB1 plays an important role in the process of NUDT1 affecting SIRT3 ubiquitination (Figure 4H).