A crosstalk between hSiah2 and Pias E3-ligases modulates Pias-dependent activation
A Depaux1, F Regnier-Ricard, A Germani
1Institut Cochin, Université Paris Descartes, CNRS (UMR 8104), Paris, France.
Oncogene
|May 30, 2007
Summary
Protein inhibitor of activated STAT (Pias) proteins are degraded by hSiah2, linking sumoylation and ubiquitination pathways. This interaction regulates protein degradation and impacts c-jun N-terminal kinase pathways.
Area of Science:
- Molecular Biology
- Cellular Biology
- Biochemistry
Background:
- Protein inhibitor of activated STAT (Pias) proteins function as E3-ligases for small ubiquitin-related modifiers (Sumo) conjugation, impacting transcription factor activity.
- Human homologues of seven in absentia (hSiah) proteins possess E3-ligase activity, targeting proteins for proteasomal degradation.
- Both Pias and hSiah proteins are involved in post-translational modifications and protein degradation pathways.
Purpose of the Study:
- To investigate the interaction between Pias and hSiah2 proteins.
- To elucidate the role of hSiah2 in regulating Pias protein stability.
- To understand the functional implications of this interaction on cellular signaling pathways.
Main Methods:
- Co-immunoprecipitation assays to identify protein interactions.
- Western blotting to assess protein degradation levels.
- Analysis of c-jun N-terminal kinase (JNK) pathway activation.
Main Results:
- Pias proteins were identified as novel interaction partners of hSiah2.
- hSiah2 specifically targets Pias proteins for proteasome-dependent degradation.
- Pias proteins do not affect hSiah2 degradation.
- hSiah2-mediated degradation of Pias regulates c-jun N-terminal kinase-activating pathways.
Conclusions:
- hSiah2 regulates Pias protein levels through proteasomal degradation.
- This study reveals a novel link between sumoylation and ubiquitination pathways.
- The interaction modulates E3-ligase availability and impacts signaling pathways like JNK.
