scholarly journals Pregnane X Receptor (PXR)-Mediated Gene Repression and Cross-Talk of PXR with Other Nuclear Receptors via Coactivator Interactions

2016 ◽  
Vol 7 ◽  
Author(s):  
Petr Pavek
Keyword(s):  
Nuclear Receptors ◽  
Cross Talk ◽  
Pregnane X Receptor ◽  
Gene Repression

scholarly journals Cross-Talk between PPARs and the Partners of RXR: A Molecular Perspective

PPAR Research ◽  
2009 ◽  
Vol 2009 ◽  
pp. 1-9 ◽  
Author(s):  
Lap Shu Alan Chan ◽  
Richard A. Wells
Keyword(s):  
Dna Binding ◽  
Nuclear Receptors ◽  
Cross Talk ◽  
Molecular Level ◽  
Signaling Networks ◽  
Future Studies ◽  
Functional Roles ◽  
Dimerization Interface ◽  
Experimental Approaches ◽  
Nuclear Receptor Subfamily

The PPARs are integral parts of the RXR-dependent signaling networks. Many other nuclear receptor subfamily 1 members also require RXR as their obligatory heterodimerization partner and they are often co-expressed in any given tissue. Therefore, the PPARs often complete with other RXR-dependent nuclear receptors and this competition has important biological implications. Thorough understanding of this cross-talk at the molecular level is crucial to determine the detailed functional roles of the PPARs. At the level of DNA binding, most RXR heterodimers bind selectively to the well-known “DR1 to 5” DNA response elements. As a result, many heterodimers share the same DR element and must complete with each other for DNA binding. At the level of heterodimerization, the partners of RXR share the same RXR dimerization interface. As a result, individual nuclear receptors must complete with each other for RXR to form functional heterodimers. Cross-talk through DNA binding and RXR heterodimerization present challenges to the study of these nuclear receptors that cannot be adequately addressed by current experimental approaches. Novel tools, such as engineered nuclear receptors with altered dimerization properties, are currently being developed. These tools will enable future studies to dissect specific RXR heterodimers and their signaling pathways.

Cross-talk between an activator of nuclear receptors-mediated transcription and the D1 dopamine receptor signaling pathway

2005 ◽  
Vol 80 (3) ◽  
pp. 379-385 ◽  
Author(s):  
Azriel Schmidt ◽  
Robert Vogel ◽  
Su Jane Rutledge ◽  
Evan E. Opas ◽  
Gideon A. Rodan ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Dopamine Receptor ◽  
Nuclear Receptors ◽  
Cross Talk ◽  
Receptor Signaling ◽  
D1 Dopamine Receptor ◽  
Receptor Signaling Pathway

Regulatory Cross-Talk between Drug Metabolism and Lipid Homeostasis: Constitutive Androstane Receptor and Pregnane X Receptor Increase Insig-1 Expression

2008 ◽  
Vol 73 (4) ◽  
pp. 1282-1289 ◽  
Author(s):  
Adrian Roth ◽  
Renate Looser ◽  
Michel Kaufmann ◽  
Sharon M. Blättler ◽  
Franck Rencurel ◽  
...  
Keyword(s):  
Drug Metabolism ◽  
Cross Talk ◽  
Constitutive Androstane Receptor ◽  
Pregnane X Receptor ◽  
Lipid Homeostasis

scholarly journals Nuclear receptor phosphorylation in xenobiotic signal transduction

2020 ◽  
Vol 295 (45) ◽  
pp. 15210-15225 ◽  
Author(s):  
Masahiko Negishi ◽  
Kaoru Kobayashi ◽  
Tsutomu Sakuma ◽  
Tatsuya Sueyoshi
Keyword(s):  
Dna Binding ◽  
Cell Signaling ◽  
Nuclear Receptors ◽  
Nuclear Receptor ◽  
Pregnane X Receptor ◽  
Receptor Activation ◽  
Binding Domain ◽  
Activation Mechanism ◽  
Dna Binding Domain ◽  
Phosphorylation Motif

Nuclear pregnane X receptor (PXR, NR1I2) and constitutive active/androstane receptor (CAR, NR1I3) are nuclear receptors characterized in 1998 by their capability to respond to xenobiotics and activate cytochrome P450 (CYP) genes. An anti-epileptic drug, phenobarbital (PB), activates CAR and its target CYP2B genes, whereas PXR is activated by drugs such as rifampicin and statins for the CYP3A genes. Inevitably, both nuclear receptors have been investigated as ligand-activated nuclear receptors by identifying and characterizing xenobiotics and therapeutics that directly bind CAR and/or PXR to activate them. However, PB, which does not bind CAR directly, presented an alternative research avenue for an indirect ligand-mediated nuclear receptor activation mechanism: phosphorylation-mediated signal regulation. This review summarizes phosphorylation-based mechanisms utilized by xenobiotics to elicit cell signaling. First, the review presents how PB activates CAR (and other nuclear receptors) through a conserved phosphorylation motif located between two zinc fingers within its DNA-binding domain. PB-regulated phosphorylation at this motif enables nuclear receptors to form communication networks, integrating their functions. Next, the review discusses xenobiotic-induced PXR activation in the absence of the conserved DNA-binding domain phosphorylation motif. In this case, phosphorylation occurs at a motif located within the ligand-binding domain to transduce cell signaling that regulates hepatic energy metabolism. Finally, the review delves into the implications of xenobiotic-induced signaling through phosphorylation in disease development and progression.

scholarly journals Embryonic and fetal β-globin gene repression by the orphan nuclear receptors, TR2 and TR4

2007 ◽  
Vol 26 (9) ◽  
pp. 2295-2306 ◽  
Author(s):  
Osamu Tanabe ◽  
David McPhee ◽  
Shoko Kobayashi ◽  
Yannan Shen ◽  
William Brandt ◽  
...  
Keyword(s):  
Nuclear Receptors ◽  
Globin Gene ◽  
Gene Repression ◽  
Orphan Nuclear Receptors

The dominant negative thyroid hormone receptor β-mutant Δ337T alters PPARα signaling in heart

2007 ◽  
Vol 292 (2) ◽  
pp. E453-E460 ◽  
Author(s):  
Norman E. Buroker ◽  
Martin E. Young ◽  
Caimiao Wei ◽  
Kyle Serikawa ◽  
Ming Ge ◽  
...  
Keyword(s):  
Gene Expression ◽  
Thyroid Hormone ◽  
Protein Content ◽  
Nuclear Receptors ◽  
Cross Talk ◽  
Target Genes ◽  
Thyroid Hormone Receptor ◽  
Dominant Negative ◽  
Variable Cross ◽  
Multiple Genes

PPARα and TR independently regulate cardiac metabolism. Although ligands for both these receptors are currently under evaluation for treatment of congestive heart failure, their interactions or signaling cooperation have not been investigated in heart. We tested the hypothesis that cardiac TRs interact with PPARα regulation of target genes and used mice exhibiting a cardioselective Δ337T TRβ1 mutation (MUT) to reveal cross-talk between these nuclear receptors. This dominant negative transgene potently inhibits DNA binding for both wild-type (WT) TRα and TRβ. We used UCP3 and MTE-1 as principal reporters and analyzed gene expression from hearts of transgenic (MUT) and nontransgenic (WT) littermates 6 h after receiving either specific PPARα ligand (WY-14643) or vehicle. Interactions were determined through qRT-PCR analyses, and the extent of these interactions across multiple genes was determined using expression arrays. In the basal state, we detected no differences between groups for protein content for UCP3, PPARα, TRα2, RXRβ, or PGC-1α. However, protein content for TRα1 and the PPARα heterodimeric partner RXRα was diminished in MUT, whereas PPARβ increased. We demonstrated cross-talk between PPAR and TR for multiple genes, including the reporters UCP3 and MTE1. WY-14643 induced a twofold increase in UCP3 gene expression that was totally abrogated in MUT. We demonstrated variable cross-talk patterns, indicating that multiple mechanisms operate according to individual target genes. The non-ligand-binding TRβ1 mutation alters expression for multiple nuclear receptors, providing a novel mechanism for interaction that has not been previously demonstrated. These results indicate that therapeutic response to PPARα ligands may be determined by thyroid hormone state and TR function.

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