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Effects of partner proteins on BCA2 RING ligase activity
Stephanie Bacopulos1, Yutaka Amemiya, Wenyi Yang
1Sunnybrook Research Institute, Toronto, ON, Canada.
BMC Cancer
|February 10, 2012
Summary
The E3 ligase BCA2 (BCA2) is stabilized by interactions with hHR23a in breast cancer cells. This stabilization is crucial for cancer progression, as BCA2 expression correlates with tumor grade.
Area of Science:
- Biochemistry
- Molecular Biology
- Oncology
Background:
- BCA2 (BCA2) is an E3 ligase associated with hormone-responsive breast cancers.
- BCA2 exhibits autoubiquitination activity and is inherently unstable.
- Previously identified BCA2 interactors included Rab7, tetherin, ubiquitin, and UBC9.
Purpose of the Study:
- To identify novel proteins that interact with BCA2.
- To investigate the functional consequences of these interactions on BCA2 stability and activity.
- To explore the correlation between BCA2 expression and clinical parameters in breast cancer.
Main Methods:
- Yeast and bacterial two-hybrid screening identified BCA2-interacting proteins.
- Immunohistochemistry (IHC) on tissue microarrays (TMAs) assessed co-expression.
- In vivo and in vitro assays examined molecular interactions and functional effects.
Main Results:
- Ten unique BCA2-interacting proteins were identified, including hHR23a and 14-3-3sigma.
- hHR23a and BCA2 showed significant co-expression and correlation in breast cancer cell lines and tumors.
- hHR23a binding reduced BCA2 ubiquitination, stabilizing BCA2; 14-3-3sigma also stabilized BCA2.
Conclusions:
- hHR23a interaction stabilizes BCA2 in breast cancer cells.
- BCA2 expression correlates with tumor grade, highlighting its importance in cancer progression.
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