USP33 and von Hippel-Lindau disease: UBP33 (encoded by USP33/VDU1) and UBP20 (encoded by USP20/VDU2) are 59% identical USP-type DUBs that interact with the tumor suppressor E3 ubiquitin ligase VHL (pVHL), mutations in which are associated with von Hippel-Lindau disease [43].