SUMO-specific protease SENP3 enhances MDM2-mediated ubiquitination of PARIS/ZNF746 in HeLa cells

Area of Science:

• Molecular Biology
• Cell Biology
• Biochemistry

Background:

• The transcriptional repressor PARIS regulates PGC-1α and is implicated in neurodegenerative diseases and cancers.
• PARIS's transcriptional repression is modulated by SUMOylation and RNF4-mediated ubiquitination, particularly in parkin-deficient cells.

Purpose of the Study:

• To investigate the regulation of PARIS ubiquitination and degradation in parkin-deficient cells.
• To identify the key proteins and pathways involved in controlling PARIS stability.

Main Methods:

• Co-immunoprecipitation to assess protein interactions (SENP3-PARIS).
• Western blotting to detect ubiquitination and degradation of PARIS.
• Small interfering RNA (siRNA) knockdown of MDM2 and expression of dominant-negative MDM2 mutant.
• Analysis of the PI3K/AKT pathway involvement.

Main Results:

• SENP3 interacts with PARIS and enhances its ubiquitination independently of PARIS SUMOylation.
• SENP3-enhanced PARIS ubiquitination promotes proteasomal degradation, requiring the E3 ligase MDM2.
• MDM2 knockdown or dominant-negative mutant inhibits PARIS ubiquitination.
• The PI3K/AKT pathway is involved in activating MDM2 for PARIS ubiquitination.

Conclusions:

• PARIS ubiquitination is regulated by SENP3-mediated activation of MDM2 in parkin-deficient cells.
• This pathway, influenced by PI3K/AKT signaling, contributes to the control of PARIS function and degradation.
• Understanding this mechanism is crucial for targeting PARIS in associated pathologies.