RAC2 and nonpapillary renal cell carcinoma: Renal proteomic analysis revealed potential substrates of NEDD4L, among which Ras-related C3 botulinum toxin substrate 2 (RAC2) was further confirmed as a novel substrate of NEDD4L through the threonine108–proline motif, and NEDD4L-mediated RAC2 upregulation was associated with ccRCC by comprehensive analysis and functional study.