The enzymes of the FATylation pathway play a pivotal role in a number of cellular processes including regulated and targeted proteasomal degradation of ubiquitylated substrate proteins (Buchsbaum et al., 2011). Three classes of enzymes are involved in the process of FATylation; the activating enzyme Uba6, conjugating enzymes (E2s) and protein ligases (E3s). UBE2Z is a member of the E2 conjugating enzyme family and cloning of the human gene was first described by Gu et al. (2007) and Jin et al. (2007). UBE2Z is widely expressed in human tissues and expression is particularly high in the placenta, pancreas, spleen and testis (Gu et al., 2007). UBE2Z has been identified as an interaction partner of FAT10. FAT10 can be transferred from Uba6 to UBE2Z in vitro and both FAT10 and UBE2Z have been co-immunoprecipitated from intact cells. Down regulation of UBE2Z by siRNA resulted in a strong reduction of endogenous conjugate formation suggesting UBE2Z is the major E2 conjugating enzyme in the FAT10 cascade (Aichem et al., 2010).
Aichem, A., C. Pelzer, et al. (2010) USE1 is a bispecific conjugating enzyme for ubiquitin and FAT10, which FAT10ylates itself in cis. Nat Commun 1: 13.
Buchsbaum, S., B. Bercovich, et al. (2011) FAT10 is a proteasomal degradation signal which is itself regulated by ubiquitination. Mol Biol Cell. (in press)
Gu, X., F. Zhao, et al. (2007) Cloning and characterization of a gene encoding the human putative ubiquitin conjugating enzyme E2Z (UBE2Z). Mol Biol Rep 34(3): 183-8.
Jin, J., X. Li, et al. (2007) Dual E1 activation systems for ubiquitin differentially regulate E2 enzyme charging. Nature 447(7148): 1135-8.