Identification and characterization of the novel protein CCDC106 that interacts with p53 and promotes its degradation

Area of Science:

• Molecular and Cellular Biology
• Cancer Research

Background:

• The CCDC106 protein was initially identified as a p53-interacting partner via yeast two-hybrid screening.
• Experimental validation of CCDC106 sequence and function was lacking.

Purpose of the Study:

• To experimentally validate the CCDC106 protein sequence and characterize its function.
• To investigate the interaction between CCDC106 and p53 protein.
• To elucidate the functional consequences of CCDC106 on p53 activity.

Main Methods:

• Identification and analysis of CCDC106 variant transcripts.
• Determination of nuclear localization signal (NLS) in CCDC106.
• Double immunofluorescence staining to assess protein colocalization.
• Co-immunoprecipitation assays to confirm in vivo interaction.
• Assays to evaluate p53 degradation and transactivity.

Main Results:

• Three CCDC106 variant transcripts were identified, all encoding an identical 280-residue protein.
• A bipartite nuclear localization signal (residues 151-164) was identified, mediating CCDC106 nuclear entry.
• Endogenous CCDC106 and p53 proteins were found to colocalize in the nucleus.
• In vivo interaction between CCDC106 and p53 was confirmed.
• CCDC106 was shown to promote p53 protein degradation and inhibit its transactivity.

Conclusions:

• CCDC106 is experimentally validated as a nuclear protein that interacts with p53.
• CCDC106 negatively regulates p53 stability and function.
• These findings implicate CCDC106 as a novel regulator of the p53 pathway in cancer.