The enzymes of the ubiquitylation pathway play a pivotal role in a number of cellular processes including regulated and targeted proteasomal degradation of substrate proteins. Three classes of enzymes are involved in the process of ubiquitylation; activating enzymes (E1s), conjugating enzymes (E2s) and protein ligases (E3s). UBE2D1 is a member of the E2 ubiquitin-conjugating enzyme family and cloning of the human gene was first described by Scheffner et al. (1994). UBE2D1 shares 89% sequence identity with its Drosophila homologue and mediates E6/UBE3A (E6AP)-induced ubiquitylation of p53 (Jensen et al., 1995; Scheffner et al., 1994). Ubiquitylation of the yeast PTS1 import receptor (pex5p) has been demonstrated in an in vitro assay in the presence of the human UBE2D1 in combination with the ring domain of the yeast E3 ligase pex10p (Williams et al., 2008). Sequence encoding the stimulated Iron transport gene SFT overlaps with intron 7 and exon 6 of UBE2D1, and RT/PCR has shown significantly upregulated levels of UBE2D1 in livers of iron-overloaded patients with hereditary hemochromatosis (Gehrke et al., 2003).
Gehrke SG, Riedel HD, Herrmann T, Hadaschik B, Bents K, Veltkamp C, Stremmel W (2003) UbcH5A, a member of human E2 ubiquitin-conjugating enzymes, is closely related to SFT, a stimulator of iron transport, and is up-regulated in hereditary hemochromatosis. Blood 101, 3288-93.
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Scheffner M, Huibregtse JM, Howley PM (1994) Identification of a human ubiquitin-conjugating enzyme that mediates the E6-AP-dependent ubiquitination of p53. Proc Natl Acad Sci USA 91, 8797-801.
Williams C, van den Berg M, Geers E, Distel B (2008) Pex10p functions as an E3 ligase for the Ubc4p-dependent ubiquitination of Pex5p. Biochem Biophys Res Commun 374, 620-4.