Dataset Information
LRP16 integrates into NF-?B transcriptional complex and is required for its functional activation.
Ontology highlight
ABSTRACT: Background
Nuclear factor ?B (NF-?B)-mediated pathways have been widely implicated in cell survival, development and tumor progression. Although the molecular events of determining NF-?B translocation from cytoplasm to nucleus have been extensively documented, the regulatory mechanisms of NF-?B activity inside the nucleus are still poorly understood. Being a special member of macro domain proteins, LRP16 was previously identified as a coactivator of both estrogen receptor and androgen receptor, and as an interactor of NF-?B coactivator UXT. Here, we investigated the regulatory role of LRP16 on NF-?B activation.Methodology
GST pull-down and coimmunoprecipitation (CoIP) assays assessed protein-protein interactions. The functional activity of NF-?B was assessed by luciferase assays, changes in expression of its target genes, and its DNA binding ability. Annexin V staining and flow cytometry analysis were used to evaluate cell apoptosis. Immunohistochemical staining of LRP16 and enzyme-linked immunosorbent assay-based evaluation of active NF-?B were performed on primary human gastric carcinoma samples.Results
We demonstrate that LRP16 integrates into NF-?B transcriptional complex through associating with its p65 component. RNA interference knockdown of the endogenous LRP16 in cells leads to impaired NF-?B activity and significantly attenuated NF-?B-dependent gene expression. Mechanistic analysis revealed that knockdown of LRP16 did not affect tumor necrosis factor ? (TNF-?)-induced nuclear translocation of NF-?B, but blunted the formation or stabilization of functional NF-?B/p300/CREB-binding protein transcription complex in the nucleus. In addition, knockdown of LRP16 also sensitizes cells to apoptosis induced by TNF-?. Finally, a positive link between LRP16 expression intensity in nuclei of tumor cells and NF-?B activity was preliminarily established in human gastric carcinoma specimens.Conclusions
Our findings not only indicate that LRP16 is a crucial regulator for NF-?B activation inside the nucleus, but also suggest that LRP16 may be an important contributor to the aberrant activation of NF-?B in tumors.
SUBMITTER: Wu Z
PROVIDER: S-EPMC3069058 | biostudies-literature | 2011 Mar
REPOSITORIES: biostudies-literature
Publications
LRP16 integrates into NF-κB transcriptional complex and is required for its functional activation.
PloS one 20110331 3
<h4>Background</h4>Nuclear factor κB (NF-κB)-mediated pathways have been widely implicated in cell survival, development and tumor progression. Although the molecular events of determining NF-κB translocation from cytoplasm to nucleus have been extensively documented, the regulatory mechanisms of NF-κB activity inside the nucleus are still poorly understood. Being a special member of macro domain proteins, LRP16 was previously identified as a coactivator of both estrogen receptor and androgen re ...[more]