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Published on: October 30, 2013
Targeting Ubc9 for cancer therapy
Yin-Yuan Mo1, Stergios J Moschos
1Department of Medical Microbiology, Immunology and Cell Biology, Southern Illinois University, PO Box 19626, Springfield, IL 62794, USA. ymo@siumed.edu
Abstract:
Ubiquitin-conjugating enzyme (Ubc9) was originally thought to be a conjugating enzyme for ubiquitylation, but was later shown to be responsible for the most recently identified type of post-translational modification, (i.e., SUMO [small ubiquitin-related modifier]) conjugation or sumoylation. Like ubiquitylation, sumoylation modulates protein function through post-translational covalent attachment to lysine residues within targeted proteins. However, although ubiquitylation can lead to protein degradation through the 26S proteasome, sumoylation does not cause protein degradation; instead, it has been implicated in other cellular processes, such as regulating the activity of transcription factors, mediating nuclear translocation of proteins or the formation of subnuclear structures. Interestingly, some proteins can be modified at the same lysine residue by both SUMO and ubiquitin, but with distinct functional consequences. Given that many proteins involved in cell-cycle regulation, proliferation, apoptosis and DNA repair are targets for sumoylation, alterations of sumoylation could ultimately have an impact on cell growth, cancer development and drug responsiveness. As Ubc9 is the sole E2-conjugating enzyme required for sumoylation, and, in particular, Ubc9 is upregulated in an increasing number of human malignancies, such as ovarian carcinoma, melanoma and lung adenocarcinoma, it is a potential target for cancer therapy.
Insights
Ubiquitin-conjugating enzyme 9 (Ubc9) is crucial for small ubiquitin-related modifier (SUMO) conjugation, a process impacting cell growth and cancer. Ubc9 upregulation in malignancies suggests its potential as a cancer therapy target.
Area of Science:
- Molecular Biology
- Biochemistry
- Cell Biology
Background:
- Ubiquitin-conjugating enzyme 9 (Ubc9) was initially identified for ubiquitylation but is now known to mediate small ubiquitin-related modifier (SUMO) conjugation (sumoylation).
- Sumoylation, distinct from ubiquitylation, modulates protein function without causing degradation, influencing transcription factors, nuclear translocation, and subnuclear structure formation.
- Some proteins undergo modification by both SUMO and ubiquitin at the same lysine residue, leading to different functional outcomes.
Purpose of the Study:
- To elucidate the role of Ubc9 in sumoylation and its implications in cellular processes.
- To explore the connection between sumoylation, cell growth, cancer development, and drug responsiveness.
- To evaluate Ubc9 as a potential therapeutic target in human malignancies.
Main Methods:
- The abstract does not detail specific experimental methods but discusses the known functions and implications of Ubc9 and sumoylation.
- Literature review and analysis of existing research on Ubc9, sumoylation, and cancer biology.
Main Results:
- Sumoylation regulates critical cellular processes including cell-cycle regulation, proliferation, apoptosis, and DNA repair.
- Alterations in sumoylation pathways can affect cell growth, cancer progression, and response to cancer therapies.
- Ubc9 is upregulated in various human cancers, including ovarian carcinoma, melanoma, and lung adenocarcinoma.
Conclusions:
- Ubc9, as the sole E2-conjugating enzyme for sumoylation, plays a vital role in cellular regulation.
- The dysregulation of sumoylation and the increased expression of Ubc9 in cancers highlight its significance in tumorigenesis.
- Ubc9 represents a promising therapeutic target for treating human malignancies.
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