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Hsp90-dependent assembly of the DBC2/RhoBTB2-Cullin3 E3-ligase complex
Jacob R Manjarrez1, Liang Sun1, Thomas Prince1
1Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, Oklahoma, United States of America.
Plos One
|March 11, 2014
Summary
The tumor suppressor DBC2 (Deleted-in-Breast Cancer 2) interacts with Hsp90 (heat shock protein 90). Hsp90 influences DBC2
Area of Science:
- Oncology
- Molecular Biology
- Protein Biochemistry
Background:
- The tumor suppressor gene DBC2 (Deleted-in-Breast Cancer 2), also known as RhoBTB2, is frequently downregulated in various cancers.
- DBC2's role in cancer pathogenesis is under investigation, with potential links to cellular regulatory pathways.
Purpose of the Study:
- To investigate the interaction between DBC2 and the Hsp90 (90 kDa heat shock protein) chaperone machinery.
- To elucidate the functional implications of Hsp90 on DBC2's GTP-binding capacity and E3 ligase complex assembly.
Main Methods:
- Protein pull-down assays were used to confirm DBC2 association with Hsp90 and its co-chaperones.
- GTP-binding assays were performed in the presence of Hsp90 inhibitors (geldanamycin) and modulators (molybdate).
- Analysis of DBC2-Cullin3-COP9 E3 ligase complex formation was conducted.
Main Results:
- Ectopically expressed DBC2 was confirmed to associate with Hsp90 and its co-chaperones.
- Hsp90 modulates DBC2's GTP-binding ability, with inhibitors suppressing and molybdate enhancing binding.
- Hsp90 is essential for the assembly of DBC2-Cullin3-COP9 E3 ubiquitin ligase complexes.
Conclusions:
- DBC2 is a client protein of the Hsp90 chaperone machine.
- Hsp90 plays a critical role in regulating DBC2 function, including its GTP-binding and E3 ligase complex assembly.
- This suggests a novel mechanism of Hsp90-mediated regulation of E3 ubiquitin ligase complexes.
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