Rad17 Translocates to Nucleolus upon UV Irradiation through Nucleolar Localization Signal in the Central Basic Domain

Area of Science:

• Cell Biology
• Molecular Biology
• Genetics

Background:

• The nucleolus is a dynamic nuclear substructure crucial for ribosomal biogenesis and mRNA translation regulation.
• DNA damage response pathways, such as the ATR pathway, are vital for maintaining genomic stability.
• Rad17 is a key protein in initiating and maintaining ATR pathway activation following DNA damage.

Purpose of the Study:

• To investigate the nucleolar localization of Rad17.
• To identify the signals responsible for Rad17's nucleolar import.
• To explore the regulation and potential function of Rad17 in the nucleolus.

Main Methods:

• Analysis of Rad17's central basic domain for localization signals.
• Use of phosphomimetic mutations to assess the role of post-translational modifications.
• Treatment with proteasome inhibitors and UV irradiation to study Rad17 accumulation.

Main Results:

• The central basic domain of Rad17 contains both nuclear and nucleolar localization signals, with overlap between them.
• Phosphomimetic mutations impair Rad17's accumulation in the nucleolus.
• Proteasome inhibition and UV irradiation enhance Rad17's presence in the nucleolus.

Conclusions:

• Rad17 localizes to the nucleolus, regulated by its central basic domain and post-translational modifications.
• UV irradiation and proteasome inhibition promote Rad17 nucleolar accumulation.
• Rad17 may play a role in the nucleolus in response to UV-induced DNA damage.