Identification of a ZU5 and death domain-containing inhibitor of NF-kappaB
Jun Zhang1, Liang-Guo Xu, Ke-Jun Han
1Department of Immunology, National Jewish Medical and Research Center, University of Colorado Health Sciences Center, Denver, Colorado 80206, USA.
Abstract:
The transcription factor NF-kappaB plays important roles in inflammation and cell survival. NF-kappaB is composed of homodimeric and heterodimeric complexes of Rel/NF-kappaB family members, including p65 (RelA), c-Rel (Rel), RelB, NF-kappaB1/p50, and NF-kappaB2/p52. Here we report the identification and characterization of a novel ZU5 and death domain-containing protein designated ZUD. In reporter gene assays, overexpression of ZUD inhibited NF-kappaB-dependent transcription induced by both tumor necrosis factor (TNF) and interleukin-1 and their downstream signaling proteins. Gel shift assays indicated that the overexpression of ZUD inhibited binding of NF-kappaB to its target sequence. ZUD is a cytoplasmic protein, and coimmunoprecipitation assays indicated that ZUD interacted with the NF-kappaB subunit p105 and transactivator p65. Consistent with its role in inhibition of NF-kappaB-dependent transcription, ZUD sensitized cells to apoptosis induced by TNF and the TNF-related apoptosis-inducing ligand (TRAIL). Our findings suggest that ZUD is an inhibitor of NF-kappaB activation and that this protein may provide an alternative regulatory mechanism for NF-kappaB-mediated transcription.
Insights
A novel protein, ZUD, inhibits NF-kappaB activation by blocking its DNA binding. This discovery reveals a new regulatory mechanism for NF-kappaB, impacting inflammation and cell survival pathways.
Area of Science:
- Molecular Biology
- Cell Biology
- Immunology
Background:
- Nuclear Factor kappa B (NF-kappaB) is a crucial transcription factor regulating inflammation and cell survival.
- NF-kappaB exists as various homo- and heterodimeric complexes of Rel/NF-kappaB family members.
- Dysregulation of NF-kappaB is implicated in numerous diseases.
Purpose of the Study:
- To identify and characterize a novel protein, ZUD, that modulates NF-kappaB activity.
- To elucidate the mechanism by which ZUD affects NF-kappaB-dependent transcription.
- To investigate the functional consequences of ZUD's interaction with NF-kappaB signaling.
Main Methods:
- Reporter gene assays to assess NF-kappaB transcriptional activity.
- Gel shift assays to evaluate NF-kappaB DNA binding.
- Coimmunoprecipitation to identify protein interactions.
- Apoptosis assays to determine cellular sensitivity to TNF and TRAIL.
Main Results:
- Overexpression of ZUD inhibited NF-kappaB-dependent transcription induced by TNF and IL-1.
- ZUD was found to inhibit the binding of NF-kappaB to its target DNA sequence.
- ZUD interacted with NF-kappaB subunits p105 and p65.
- ZUD sensitized cells to TNF- and TRAIL-induced apoptosis.
Conclusions:
- ZUD acts as an inhibitor of NF-kappaB activation.
- ZUD's mechanism involves blocking NF-kappaB DNA binding and interacting with key NF-kappaB subunits.
- ZUD represents a novel regulatory component of NF-kappaB signaling, potentially influencing inflammatory responses and cell fate.
