Ubiquitin-conjugating enzyme E2 I (UBC9) (UBC9)

SUMO-conjugating enzyme UBC9, encoded by the UBE2I gene, is the sole E2 conjugating enzyme in the sumoylation pathway, a critical post-translational modification system [1, 2]. It facilitates the transfer of Small Ubiquitin-like Modifier (SUMO) proteins from the E1 activating complex to a wide array of substrate proteins, often recognizing a specific consensus motif (ΨKxD/E) [2, 13]. UBC9 plays a fundamental role in regulating diverse cellular processes, including nuclear transport, transcriptional regulation, DNA repair, and cell cycle progression [1, 11]. In many human malignancies, such as breast, gastric, and ovarian cancers, UBC9 is frequently overexpressed and correlates with poor prognosis, promoting tumor cell proliferation, invasion, and chemoresistance [7, 15, 16]. Beyond oncology, it is implicated in viral infections, neurodegenerative disorders, and cardiovascular health [2, 10, 22]. Therapeutic strategies targeting UBC9 involve small molecule inhibitors like ginkgolic acid and 2-D08, which aim to block its catalytic activity or allosterically modulate its function [5, 6, 21]. However, because UBC9 is essential for normal cell viability and development, achieving therapeutic selectivity without systemic toxicity remains a significant challenge [6, 12, 18].

Other names

UBE2IP18UBCE9C358B7.1Ubiquitin carrier protein 9Ubiquitin carrier protein IUbiquitin-conjugating enzyme E2 ISUMO-protein ligaseSUMO-conjugating enzyme UBC9

Inhibition of SUMO E2 conjugating activity, blocking formation of UBC9-SUMO thioester complex, and allosteric inhibition of sumoylation [5, 6, 8].