Alternative titles; symbols
HGNC Approved Gene Symbol: UBE2G2
Cytogenetic location: 21q22.3 Genomic coordinates (GRCh38) : 21:44,768,580-44,801,820 (from NCBI)
In eukaryotes, conjugation of target proteins to ubiquitin is an essential step in the proteasome-dependent degradation process and is mediated by a family of ubiquitin-conjugating (UBC) enzymes. See 600012. Katsanis and Fisher (1998) stated that S. cerevisiae Ubc7 is an endoplasmic reticulum-bound molecule whose active site faces the cytosol. Ubc7 has been shown to confer resistance to cadmium and to participate in the degradation of specific yeast proteins. As part of an effort to generate a transcriptional map of human chromosome 21, Katsanis and Fisher (1998) identified UBE2G2 cDNAs. The predicted 165-amino acid protein shares 60% sequence identity with yeast Ubc7. The nucleotide sequence of UBE2G2 is 57% similar to that of UBE2G1 (601569), another human Ubc7 homolog. Northern blot analysis revealed that UBE2G2 is expressed ubiquitously as 2.9- and 7-kb mRNAs. The highest level of expression was seen in skeletal muscle.
To dissect the mechanism of ubiquitin ligase (E3) catalysis, Li et al. (2007) used mouse Ube2g2, a ubiquitin-conjugating enzyme (E2) identical at the amino acid level to human UBE2G2, and a human E3, GP78 (603243), an endoplasmic reticulum (ER)-associated conjugating system essential for the degradation of misfolded ER proteins. Li et al. (2007) demonstrated by expressing recombinant proteins in E. coli that Ube2g2/GP78-mediated polyubiquitination involves preassembly of lys48-linked ubiquitin chains at the catalytic cysteine of Ube2g2. The growth of Ube2g2-anchored ubiquitin chains seems to be mediated by an aminolysis-based transfer reaction between 2 Ube2g2 molecules that each carries a ubiquitin moiety in its active site. The authors noted that their results, which support a 'preassembly' model in which polyubiquitination of a substrate can be achieved by transferring preassembled ubiquitin chains from Ube2g2 to a lysine residue in a substrate, is distinct from the generally presumed 'sequential addition' model, in which ubiquitin molecules are added one at a time, first to a lysine residue in a substrate and then to lys48 in the distal ubiquitin of a growing chain.
By inclusion within mapped clones and by analysis of somatic cell hybrid panels, Katsanis and Fisher (1998) mapped the UBE2G2 gene to 21q22.3. Rose et al. (1998) confirmed the localization to 21q22.3 by FISH.
Katsanis, N., Fisher, E. M. C. Identification, expression, and chromosomal localization of ubiquitin conjugating enzyme 7 (UBE2G2), a human homologue of the Saccharomyces cerevisiae Ubc7 gene. Genomics 51: 128-131, 1998. [PubMed: 9693041] [Full Text: https://doi.org/10.1006/geno.1998.5263]
Li, W., Tu, D., Brunger, A. T., Ye, Y. A ubiquitin ligase transfers preformed polyubiquitin chains from a conjugating enzyme to a substrate. Nature 446: 333-337, 2007. [PubMed: 17310145] [Full Text: https://doi.org/10.1038/nature05542]
Rose, S. A., Leek, J. P., Moynihan, T. P., Ardley, H. C., Markham, A. F., Robinson, P. A. Assignment of the ubiquitin conjugating enzyme gene, UBE2G2, to human chromosome band 21q22.3 by in situ hybridization. Cytogenet. Cell Genet. 83: 98-99, 1998. [PubMed: 9925943] [Full Text: https://doi.org/10.1159/000015141]