Table 2.

DUBs classification.

Categories	Families	DUBs
Cysteine proteases	USP	USP 1-8, USP 9X, USP 9Y, USP 10-16, USP 17 L1, USP 17 L2, USP 18-26, USP 27X, USP 28-54, USP L1, CYLD
	UCH	UCH L1, UCH L3, UCH L5, BAP1
	MJD	ATXN3, ATXN3L, JOSD1, JOSD2
	OTU	OTUB1, OTUB2, OTUD1, OTUD3, OTUD4, OTUD5, OTUD6A, OTUD6B, OTUD7A, OTUD7B, A2O, HIN1L, VCPIP1, TRABID, YOD1
	MINDY	FAM63A, FAM63B, FAM188A, FAM188B
Metalloproteases	JAMM	AMSH, AMSH-LP, BRCC36, COPS5, COPS6, EIF3F, EIF3H, MPND, MYSM1, PSMD7, PSMD14, PRPF8

Six classes of DUBs in the human genome are classified into two categories, cysteine proteases, and metalloproteases. Five classes are cysteine proteases: USP, ubiquitin-specific proteases; UCH, ubiquitin carboxyl-terminal hydrolases; MJD, Machado-Joseph disease protein domain proteases; OTU, ovarian-tumor proteases; MINDY, motif interacting with Ub-containing DUB family. One class is metalloproteases: JAMM, JAMM/MPN domain-associated metallopeptidases.