Rev7/MAD2B links c-Jun N-terminal protein kinase pathway signaling to activation of the transcription factor Elk-1

Area of Science:

• Molecular Biology
• Cell Signaling
• Genetics

Background:

• Mitogen-activated protein (MAP) kinases are crucial for eukaryotic cells to interpret external signals.
• MAP kinase cascades modulate gene expression by targeting transcription factors like Elk-1.
• Elk-1 activity is regulated by phosphorylation, influencing its transcriptional function.

Purpose of the Study:

• To identify novel interaction partners of the transcription factor Elk-1.
• To investigate the role of human Rev7 (hRev7) in regulating Elk-1 activity.
• To elucidate the involvement of hRev7 in cellular responses to DNA damage.

Main Methods:

• Co-immunoprecipitation to identify protein interactions.
• In vitro kinase assays to assess protein phosphorylation.
• Quantitative gene expression analysis (e.g., egr-1) following DNA damage induction.

Main Results:

• Human Rev7 (hRev7) was identified as a binding partner of Elk-1.
• hRev7 was shown to promote Elk-1 phosphorylation by c-Jun N-terminal kinase (JNK).
• hRev7 facilitates the upregulation of Elk-1 target genes (e.g., egr-1) under DNA-damaging conditions.

Conclusions:

• hRev7 directly interacts with Elk-1 and enhances its JNK-mediated phosphorylation.
• hRev7 plays a significant role in the transcriptional response to DNA damage by modulating Elk-1 activity.
• These findings suggest hRev7 has a widespread function in coordinating cellular responses to DNA damage, beyond its known roles in DNA repair and cell cycle control.