Ubiquitin-dependent recruitment of SLFN11 to chromatin is regulated by deubiquitinase (DUB) and RNF168

Area of Science:

• Molecular Biology
• Cancer Research
• Chromatin Biology

Background:

• SLFN11 (Schlafen Family Member 11) is a key protein involved in DNA damage response and transcriptional regulation.
• The precise mechanisms governing SLFN11's recruitment to chromatin are not fully understood.
• Understanding SLFN11 chromatin dynamics is crucial for developing targeted cancer therapies.

Purpose of the Study:

• To elucidate the molecular mechanisms of SLFN11 chromatin recruitment.
• To identify specific cellular pathways and modifications that regulate SLFN11 localization.
• To differentiate SLFN11 recruitment mechanisms induced by different stimuli.

Main Methods:

• High-throughput imaging of U2OS cells expressing inducible SLFN11.
• Screening of 162 oncology-focused compounds, including deubiquitinase (DUB) inhibitors.
• Utilizing specific inhibitors like TAK243 to assess ubiquitylation dependency.
• Investigating the role of RNF168 in SLFN11 ubiquitylation and chromatin association.

Main Results:

• Deubiquitinase inhibitors, such as VLX-1570, induce robust SLFN11 chromatin recruitment, particularly at promoter regions, suppressing transcription.
• SLFN11 recruitment by DUB inhibitors is ubiquitin-dependent and distinct from DNA damage-induced recruitment at replication forks.
• TAK243 inhibits SLFN11 chromatin recruitment by both DUB inhibitors and DNA damage, confirming ubiquitylation dependency.
• RNF168 is essential for SLFN11 ubiquitylation and subsequent chromatin association.
• Specific ubiquitylation sites (lysines 390, 391, 429) and K27-linked polyubiquitin chains on SLFN11 are critical for its chromatin recruitment.

Conclusions:

• SLFN11 chromatin recruitment is critically dependent on its ubiquitylation, particularly by RNF168.
• Deubiquitinase inhibitors represent a novel class of compounds that can modulate SLFN11 localization and function.
• Ubiquitylation of SLFN11 plays a vital role in its transcriptional regulatory activities at promoter regions, offering potential therapeutic strategies.