Possible multifunctional enzyme with both glycosyltransferase and deubiquitinase activities. May be involved in protein N-glycosylation, second step of the dolichol-linked oligosaccharide pathway. N-acetyl-alpha-D-glucosaminyl-diphosphodolichol + UDP-N-acetyl-alpha-D-glucosamine = H(+) + N,N'-diacetylchitobiosyl diphosphodolichol + UDP Thiol-dependent hydrolysis of ester, thioester, amide, peptide and isopeptide bonds formed by the C-terminal Gly of ubiquitin (a 76-residue protein attached to proteins as an intracellular targeting signal). Isoform 2 may interact with ALG14. Could be recruited to the cytosolic face of the endoplasmic reticulum membrane through its interaction with ALG14. Contains 1 OTU domain with intact active sites. No deubiquitinase activity has been detected when tested (PubMed:23827681). The disease is caused by variants affecting the gene represented in this entry. Belongs to the glycosyltransferase 28 family. Truncated N-terminus. Truncated N-terminus. Truncated N-terminus. Truncated N-terminus. Truncated N-terminus. Truncated C-terminus.