UBB and Alzheimer disease: Furthermore, DUBs such as UCHL1, USP10, and USP11, as well as the E2 enzyme of E2-25K/HIP-2, and a frameshift ubiquitin mutant with 20 extra amino acid residues at its C-terminus (UBB+1), are reportedly involved in AD (Upadhya and Hegde 2007; Wei et al., 2022; Yan et al., 2022).