Chromatin constitutes a repressive barrier to the process of ligand-dependent transcriptional activity of nuclear receptors. Nucleosomes prevent the binding of estrogen receptor α (ERα) in absence of ligand and thus represent an important level of transcriptional regulation. Here, we show that in breast cancer MCF-7 cells, TLE3, a co-repressor of the Groucho/Grg/TLE family, interacts with FoxA1 and is detected at regulatory elements of ERα target genes in absence of estrogen.
View Article and Find Full Text PDFAdipogenesis, the biological process by which preadipocytes differentiate into mature fat cells, is coordinated by a tightly regulated gene expression program. Indeed, it has been reported that a large number of genetic events, from fat cell-specific transcription factors expression, such as the master regulator of fat cell differentiation peroxisome proliferator-activated receptor (PPAR)γ2 to epigenetic modifications, govern the acquisition of a mature adipocyte phenotype. Here, we provide evidence that the E1A-binding protein p400 (p400) complex subunit bromo-containing protein 8 (Brd8) plays an important role in the regulation of PPARγ target genes during adipogenesis by targeting and incorporating the histone variant H2A.
View Article and Find Full Text PDFBiochem Biophys Res Commun
September 2011
DLK, a serine/threonine kinase that functions as an upstream activator of the mitogen-activated protein kinase (MAPK) pathways, has been shown to play a role in development, cell differentiation, apoptosis and neuronal response to injury. Interestingly, recent studies have shown that DLK may also be required for cell proliferation, although little is known about its specific functions. To start addressing this issue, we studied how DLK expression is modulated during cell cycle progression and what effect DLK depletion has on cell proliferation in WI-38 fibroblasts.
View Article and Find Full Text PDFDLK (dual leucine zipper-bearing kinase) is a key regulator of development, cell differentiation and apoptosis. Interestingly, recent studies have shown that DLK expression is up-regulated in 3T3-L1 cells induced to differentiate into adipocytes and that DLK knockdown impairs the expression of PPARγ (peroxisome-proliferator-activated receptor γ), a master regulator of adipogenesis. Because the PPARγ agonist rosiglitazone was found to increase DLK expression in 3T3-L1 cells, we hypothesized that PPARγ is required for the transcriptional activation of the DLK gene.
View Article and Find Full Text PDFBackground: The mixed-lineage kinase (MLK) family member DLK has been proposed to serve as a regulator of differentiation in various cell types; however, its role in adipogenesis has not been investigated. In this study, we used the 3T3-L1 preadipocyte cell line as a model to examine the function of DLK in adipocyte differentiation.
Methods And Findings: Immunoblot analyses and kinase assays performed on 3T3-L1 cells showed that the expression and activity of DLK substantially increase as differentiation occurs.
It has been recently proposed that the second extracellular loop of the human bradykinin (BK) B1 receptor (B1R) contains a conserved HExxH motif also present in peptidases possessing a Zn2+ prosthetic group, such as angiotensin converting enzyme (ACE), and that ACE inhibitors directly activate B1R signaling in endothelial cells. However, the binding of ACE inhibitors to the B1Rs has never been directly evaluated. Information about binding of a radiolabeled inhibitor to natural or recombinant ACE in intact cells (physiologic ionic composition) was also collected.
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