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Cul3 substrate adaptor SPOP targets Nup153 for degradation
Joseph Y Ong1, Mai Abdusamad1, Ivan Ramirez1
1Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095.
Molecular Biology of the Cell
|January 9, 2025
Summary
The study identifies Nuclear Pore Protein 153 (Nup153) as a novel substrate of Speckle-type POZ protein (SPOP). SPOP regulates Nup153 levels, impacting cell proliferation and homeostasis.
Area of Science:
- Cell Biology
- Molecular Biology
- Cancer Research
Background:
- Speckle-type POZ protein (SPOP) is a crucial E3 ubiquitin ligase adaptor regulating protein degradation.
- Dysregulation of SPOP is implicated in cancer progression by affecting cell growth and proliferation.
- Understanding SPOP substrates is key to deciphering its role in cellular homeostasis.
Purpose of the Study:
- To identify novel substrates of SPOP.
- To investigate the functional relationship between SPOP and its newly identified substrate, Nup153.
- To elucidate the impact of SPOP-Nup153 interaction on cellular processes.
Main Methods:
- Co-immunoprecipitation to confirm SPOP-Nup153 binding.
- Immunofluorescence microscopy to assess subcellular localization.
- RNA interference (RNAi) to deplete SPOP levels.
- Western blotting to analyze protein stability.
Main Results:
- Nuclear Pore Protein 153 (Nup153) was identified as a novel SPOP substrate.
- SPOP and Nup153 interact and colocalize at the nuclear envelope.
- SPOP mediates Nup153 ubiquitylation and degradation; SPOP depletion stabilizes Nup153.
- Loss of SPOP enhances nuclear envelope localization of Mad1, a protein tethered by Nup153.
Conclusions:
- SPOP directly regulates Nup153 protein levels.
- This regulation impacts nuclear pore complex function and spindle assembly checkpoint.
- Findings expand the understanding of SPOP's role in protein homeostasis and cell proliferation control.
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