scholarly journals Neuronal Activity-Induced BRG1 Phosphorylation Regulates Enhancer Activation

2020 ◽  
Author(s):  
Bongwoo Kim ◽  
Yi Luo ◽  
Xiaoming Zhan ◽  
Zilai Zhang ◽  
Xuanming Shi ◽  
...  
Keyword(s):  
Rna Polymerase Ii ◽  
Chromatin Remodeling ◽  
Neuronal Activity ◽  
Phosphorylation Site ◽  
Serine Phosphorylation ◽  
Dependent Manner ◽  
Enhancer Rna ◽  
Induce Activity ◽  
Chromatin Remodeling Complexes ◽  
Activity Dependent

SUMMARYNeuronal activity-induced enhancers drive the gene induction in response to stimulation. Here, we demonstrate that BRG1, the core subunit of SWI/SNF-like BAF ATP-dependent chromatin remodeling complexes, regulates neuronal activity-induced enhancers. Upon stimulation, BRG1 is recruited to enhancers in an H3K27Ac-dependent manner. BRG1 regulates enhancer basal activities and inducibility by affecting cohesin binding, enhancer-promoter looping, RNA polymerase II recruitment, and enhancer RNA expression. Furthermore, we identified a serine phosphorylation site in BRG1 that is induced by neuronal activities and is sensitive to CaMKII inhibition. BRG1 phosphorylation affects its interaction with several transcription co-factors, possibly modulating BRG1 mediated transcription outcomes. Using mice with knock-in mutations, we showed that non-phosphorylatable BRG1 fails to efficiently induce activity-dependent genes, whereas phosphomimic BRG1 increases the enhancer activities and inducibility. These mutant mice displayed anxiety-like phenotypes and altered responses to stress. Therefore, our data reveal a mechanism connecting neuronal signaling to enhancer activities through BRG1 phosphorylation.

scholarly journals Chromatin Remodeling Complexes Interact Dynamically with a Glucocorticoid Receptor–regulated Promoter

2008 ◽  
Vol 19 (8) ◽  
pp. 3308-3322 ◽  
Author(s):  
Thomas A. Johnson ◽  
Cem Elbi ◽  
Bhavin S. Parekh ◽  
Gordon L. Hager ◽  
Sam John
Keyword(s):  
Rna Polymerase Ii ◽  
Chromatin Remodeling ◽  
Transcriptional Activation ◽  
Tandem Repeats ◽  
Inducible Promoter ◽  
Kinetic Properties ◽  
Dependent Manner ◽  
Chromatin Remodeling Complexes ◽  
Mmtv Promoter

Brahma (BRM) and Brahma-related gene 1 (BRG1) are the ATP-dependent catalytic subunits of the SWI/SNF family of chromatin-remodeling complexes. These complexes are involved in essential processes such as cell cycle, growth, differentiation, and cancer. Using imaging approaches in a cell line that harbors tandem repeats of stably integrated copies of the steroid responsive MMTV-LTR (mouse mammary tumor virus–long terminal repeat), we show that BRG1 and BRM are recruited to the MMTV promoter in a hormone-dependent manner. The recruitment of BRG1 and BRM resulted in chromatin remodeling and decondensation of the MMTV repeat as demonstrated by an increase in the restriction enzyme accessibility and in the size of DNA fluorescence in situ hybridization (FISH) signals. This chromatin remodeling event was concomitant with an increased occupancy of RNA polymerase II and transcriptional activation at the MMTV promoter. The expression of ATPase-deficient forms of BRG1 (BRG1-K-R) or BRM (BRM-K-R) inhibited the remodeling of local and higher order MMTV chromatin structure and resulted in the attenuation of transcription. In vivo photobleaching experiments provided direct evidence that BRG1, BRG1-K-R, and BRM chromatin-remodeling complexes have distinct kinetic properties on the MMTV array, and they dynamically associate with and dissociate from MMTV chromatin in a manner dependent on hormone and a functional ATPase domain. Our data provide a kinetic and mechanistic basis for the BRG1 and BRM chromatin-remodeling complexes in regulating gene expression at a steroid hormone inducible promoter.

Extracellular Release of ILEI/FAM3C and Amyloid-β Is Associated with the Activation of Distinct Synapse Subpopulations

2021 ◽  
pp. 1-16
Author(s):  
Masaki Nakano ◽  
Yachiyo Mitsuishi ◽  
Lei Liu ◽  
Naoki Watanabe ◽  
Emi Hibino ◽  
...  
Keyword(s):  
Neuronal Activity ◽  
Epithelial Mesenchymal Transition ◽  
Surrogate Marker ◽  
Amyloid Β ◽  
Dependent Manner ◽  
Mesenchymal Transition ◽  
Extracellular Release ◽  
Activity Dependent ◽  
Aβ Production

Background: Brain amyloid-β (Aβ) peptide is released into the interstitial fluid (ISF) in a neuronal activity-dependent manner, and Aβ deposition in Alzheimer’s disease (AD) is linked to baseline neuronal activity. Although the intrinsic mechanism for Aβ generation remains to be elucidated, interleukin-like epithelial-mesenchymal transition inducer (ILEI) is a candidate for an endogenous Aβ suppressor. Objective: This study aimed to access the mechanism underlying ILEI secretion and its effect on Aβ production in the brain. Methods: ILEI and Aβ levels in the cerebral cortex were monitored using a newly developed ILEI-specific ELISA and in vivo microdialysis in mutant human Aβ precursor protein-knockin mice. ILEI levels in autopsied brains and cerebrospinal fluid (CSF) were measured using ELISA. Results: Extracellular release of ILEI and Aβ was dependent on neuronal activation and specifically on tetanus toxin-sensitive exocytosis of synaptic vesicles. However, simultaneous monitoring of extracellular ILEI and Aβ revealed that a spontaneous fluctuation of ILEI levels appeared to inversely mirror that of Aβ levels. Selective activation and inhibition of synaptic receptors differentially altered these levels. The evoked activation of AMPA-type receptors resulted in opposing changes to ILEI and Aβ levels. Brain ILEI levels were selectively decreased in AD. CSF ILEI concentration correlated with that of Aβ and were reduced in AD and mild cognitive impairment. Conclusion: ILEI and Aβ are released from distinct subpopulations of synaptic terminals in an activity-dependent manner, and ILEI negatively regulates Aβ production in specific synapse types. CSF ILEI might represent a surrogate marker for the accumulation of brain Aβ.

scholarly journals The Transition of Poised RNA Polymerase II to an Actively Elongating State Is a “Complex” Affair

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Marie N. Yearling ◽  
Catherine A. Radebaugh ◽  
Laurie A. Stargell
Keyword(s):  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Chromatin Remodeling ◽  
Transcriptional Activation ◽  
Quarter Century ◽  
Evolutionary Spectrum ◽  
Chromatin Remodeling Complexes ◽  
Initial Discovery ◽  
Transcription Complexes ◽  
Productive Elongation

The initial discovery of the occupancy of RNA polymerase II at certain genes prior to their transcriptional activation occurred a quarter century ago in Drosophila. The preloading of these poised complexes in this inactive state is now apparent in many different organisms across the evolutionary spectrum and occurs at a broad and diverse set of genes. In this paper, we discuss the genetic and biochemical efforts in S. cerevisiae to describe the conversion of these poised transcription complexes to the active state for productive elongation. The accumulated evidence demonstrates that a multitude of coactivators and chromatin remodeling complexes are essential for this transition.

scholarly journals Phosphorylation of Connexin36 near the C-terminus switches binding affinities for PDZ-domain and 14–3–3 proteins in vitro

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Stephan Tetenborg ◽  
Helen Y. Wang ◽  
Lena Nemitz ◽  
Anne Depping ◽  
Alexsandra B. Espejo ◽  
...  
Keyword(s):  
Gap Junctions ◽  
Binding Affinity ◽  
Protein Microarray ◽  
Pdz Domain ◽  
Phosphorylation Site ◽  
Binding Domain ◽  
Dependent Manner ◽  
C Terminus ◽  
Activity Dependent

Abstract Connexin36 (Cx36) is the most abundant connexin in central nervous system neurons. It forms gap junction channels that act as electrical synapses. Similar to chemical synapses, Cx36-containing gap junctions undergo activity-dependent plasticity and complex regulation. Cx36 gap junctions represent multimolecular complexes and contain cytoskeletal, regulatory and scaffolding proteins, which regulate channel conductance, assembly and turnover. The amino acid sequence of mammalian Cx36 harbors a phosphorylation site for the Ca2+/calmodulin-dependent kinase II at serine 315. This regulatory site is homologous to the serine 298 in perch Cx35 and in close vicinity to a PDZ binding domain at the very C-terminal end of the protein. We hypothesized that this phosphorylation site may serve as a molecular switch, influencing the affinity of the PDZ binding domain for its binding partners. Protein microarray and pulldown experiments revealed that this is indeed the case: phosphorylation of serine 298 decreased the binding affinity for MUPP1, a known scaffolding partner of connexin36, and increased the binding affinity for two different 14–3–3 proteins. Although we did not find the same effect in cell culture experiments, our data suggest that phosphorylation of serine 315/298 may serve to recruit different proteins to connexin36/35-containing gap junctions in an activity-dependent manner.

scholarly journals Histone H3K4me1 and H3K27ac play roles in nucleosome depletion and eRNA transcription, respectively, at enhancers

2021 ◽  
Author(s):  
Yujin Kang ◽  
Yea Woon Kim ◽  
Jin Kang ◽  
AeRi Kim
Keyword(s):  
Target Genes ◽  
K562 Cells ◽  
Reciprocal Effects ◽  
Dependent Manner ◽  
Set Domain ◽  
Histone Methyltransferases ◽  
Enhancer Rna ◽  
Genome Wide ◽  
Chromatin Remodeling Complexes

ABSTRACTHistone H3K4me1 and H3K27ac are enhancer specific modifications and are required for enhancers to activate transcription of target genes. However the reciprocal effects of these histone modifications on each other and their roles in enhancers are not clear. Here to comparatively analyze the role of these modifications, we inhibited H3K4me1 and H3K27ac by deleting SET domain of histone methyltransferases MLL3 and MLL4 and HAT domain of histone acetyltransferase p300, respectively, in erythroid K562 cells. The loss of H3K4me1 reduced H3K27ac at the β-globin enhancer LCR HSs, but H3K27ac reduction did not affect H3K4me1. This unequal relationship between two modifications was revealed in putative enhancers by genome-wide analysis using ChIP-seq. Histone H3 depletion at putative enhancers was weakened by the loss of H3K4me1 but not by the loss of H3K27ac. Chromatin remodeling complexes were recruited into the β-globin LCR HSs in a H3K4me1-dependent manner. In contrast, H3K27ac was required for enhancer RNA (eRNA) transcription, and H3K4me1 was not enough for it. Forced H3K27ac induced eRNA transcription without affecting H3K4me1 at the β-globin LCR HSs. These results indicate that H3K4me1 and H3K27ac affect each other in different ways and play more direct roles in nucleosome depletion and eRNA transcription, respectively, at enhancers.

scholarly journals Octamer Transfer and Creation of Stably Remodeled Nucleosomes by Human SWI-SNF and Its Isolated ATPases

2000 ◽  
Vol 20 (17) ◽  
pp. 6380-6389 ◽  
Author(s):  
Michael L. Phelan ◽  
Gavin R. Schnitzler ◽  
Robert E. Kingston
Keyword(s):  
Chromatin Remodeling ◽  
Dependent Manner ◽  
Chromatin Remodeling Complexes ◽  
Atpase Subunits ◽  
Histone Octamers

ABSTRACT Chromatin remodeling complexes help regulate the structure of chromatin to facilitate transcription. The multisubunit human (h) SWI-SNF complex has been shown to remodel mono- and polynucleosome templates in an ATP-dependent manner. The isolated hSWI-SNF ATPase subunits BRG1 and hBRM also have these activities. The intact complex has been shown to produce a stable remodeled dimer of mononucleosomes as a product. Here we show that the hSWI-SNF ATPases alone can also produce this product. In addition, we show that hSWI-SNF and its ATPases have the ability to transfer histone octamers from donor nucleosomes to acceptor DNA. These two reactions are characterized and compared. Our results are consistent with both products of SWI-SNF action being formed as alternative outcomes of a single remodeling mechanism. The ability of the isolated ATPase subunits to catalyze these reactions suggests that these subunits play a key role in determining the mechanistic capabilities of the SWI-SNF family of remodeling complexes.

scholarly journals MyoD Targets Chromatin Remodeling Complexes to the Myogenin Locus Prior to Forming a Stable DNA-Bound Complex

2005 ◽  
Vol 25 (10) ◽  
pp. 3997-4009 ◽  
Author(s):  
Ivana L. de la Serna ◽  
Yasuyuki Ohkawa ◽  
Charlotte A. Berkes ◽  
Donald A. Bergstrom ◽  
Caroline S. Dacwag ◽  
...  
Keyword(s):  
Chromatin Remodeling ◽  
Dominant Negative ◽  
Regulatory Proteins ◽  
Specific Gene ◽  
Dependent Manner ◽  
Independent Manner ◽  
Chromatin Remodeling Complexes ◽  
Direct Binding ◽  
Induced Genes ◽  
Step Mechanism

ABSTRACT The activation of muscle-specific gene expression requires the coordinated action of muscle regulatory proteins and chromatin-remodeling enzymes. Microarray analysis performed in the presence or absence of a dominant-negative BRG1 ATPase demonstrated that approximately one-third of MyoD-induced genes were highly dependent on SWI/SNF enzymes. To understand the mechanism of activation, we performed chromatin immunoprecipitations analyzing the myogenin promoter. We found that H4 hyperacetylation preceded Brg1 binding in a MyoD-dependent manner but that MyoD binding occurred subsequent to H4 modification and Brg1 interaction. In the absence of functional SWI/SNF enzymes, muscle regulatory proteins did not bind to the myogenin promoter, thereby providing evidence for SWI/SNF-dependent activator binding. We observed that the homeodomain factor Pbx1, which cooperates with MyoD to stimulate myogenin expression, is constitutively bound to the myogenin promoter in a SWI/SNF-independent manner, suggesting a two-step mechanism in which MyoD initially interacts indirectly with the myogenin promoter and attracts chromatin-remodeling enzymes, which then facilitate direct binding by MyoD and other regulatory proteins.

scholarly journals PKCα-dependent interaction of otoferlin and calbindin: evidence for regulation of endocytosis in inner hair cells

2019 ◽  
Author(s):  
Andreia P. Cepeda ◽  
Hanan Al-Moyed ◽  
Christof Lenz ◽  
Henning Urlaub ◽  
Ellen Reisinger
Keyword(s):  
Hair Cell ◽  
Serine Phosphorylation ◽  
Dependent Manner ◽  
Myosin Vi ◽  
Inner Hair Cell ◽  
Signaling Complex ◽  
Calbindin D28k ◽  
Vesicle Cycle ◽  
Activity Dependent

AbstractOtoferlin is essential for the fast and indefatigable release of synaptic vesicles at auditory inner hair cell (IHC) ribbon synapses, being involved in exocytic, endocytic and regenerative steps of the synaptic vesicle cycle. Serving diverse functions at this highly dynamic synapse implies that this multi-C2 domain protein is precisely regulated. Here we found protein kinase C α (PKCα) and otoferlin to colocalize in endocytic recycling compartments upon IHC depolarization and to interact in an activity-dependent manner. In vitro assays confirmed that PKCα can phosphorylate otoferlin at five serine residues, which correlates with increased serine phosphorylation in <40 nm proximity to otoferlin in murine IHCs that can be fully blocked by combining PKC and CaMKII inhibitors. Moreover, otoferlin interacts with calbindin-D28k in stimulated IHCs, which was precluded when PKCα was inhibited. Similarly, the activity-dependent increase in otoferlin-myosin VI interaction depends on PKCα activation. We propose that upon strong hair cell depolarization, PKCα phosphorylates otoferlin, thereby enabling it to interact with calbindin-D28k and myosin VI, building a Ca2+-dependent signaling complex that possibly regulates different modes of endocytosis.

scholarly journals Protein Kinase C δ Associates with the Interleukin-6 Receptor Subunit Glycoprotein (gp) 130 via Stat3 and Enhances Stat3-gp130 Interaction

2002 ◽  
Vol 277 (51) ◽  
pp. 49134-49142 ◽  
Author(s):  
Veronica Novotny-Diermayr ◽  
Tong Zhang ◽  
Lei Gu ◽  
Xinmin Cao
Keyword(s):  
Protein Kinase ◽  
Catalytic Domain ◽  
Nuclear Translocation ◽  
Phosphorylation Site ◽  
Initial Step ◽  
Dominant Negative ◽  
Serine Phosphorylation ◽  
Dependent Manner ◽  
Transactivation Domain ◽  
Receptor Subunit

The transcriptional regulation of Stat proteins is controlled through their C-terminal domains, which harbor both a tyrosine phosphorylation site, required for dimerization and subsequent nuclear translocation, and a serine phosphorylation site, required for maximum transcriptional activity. Previously, we reported that protein kinase Cδ (PKCδ) phosphorylates and interacts with Stat3 in an interleukin (IL)-6-dependent manner. In this study, we further characterized this interaction, and investigated the potential role of such an interaction. We show here that the catalytic domain of PKCδ interacts with the Src homology 2 domain and part of the adjacent C-terminal transactivation domain of Stat3. This interaction, which does not seem to involve a classical phosphotyrosine SH2-mediated binding, however, significantly enhances the interaction of Stat3 and the IL-6 receptor subunit glycoprotein (gp) 130, which is the initial step for Stat3 activation by IL-6. Expression of a dominant negative PKCδ or depletion of the endogenous PKCδ by phorbol 12-myristate 3-acetate treatment abrogates the association of Stat3 with gp130. At the same time, PKCδ is recruited to gp130 via association with Stat3, which may facilitate its phosphorylation on the gp130 receptor. Finally, we identified Thr-890, a putative PKC phosphorylation site on gp130, to be critical for the effect of PKCδ. Our data indicate that PKCδ plays important regulatory roles in IL-6 signaling.

Abstract 1357: PGC-1 α as a Novel Regulator for Angiotensin II-induced Reactive Oxygen Species Production and Hypertrophy in Vascular Smooth Muscle Cells

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Shiqin Xiong ◽  
Mushtaq Ahmad ◽  
Nikolay A Patrushev ◽  
Lula Hilenski ◽  
San Martin Almeyda Alejandra ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Smooth Muscle ◽  
Angiotensin Ii ◽  
Vascular Smooth Muscle ◽  
Phosphorylation Site ◽  
Serine Phosphorylation ◽  
H2o2 Production ◽  
Dependent Manner ◽  
Ang Ii ◽  
Akt Inhibitor

Angiotensin II (Ang II) increases H 2 O 2 production and vascular smooth muscle cell (VSMCs) hypertrophy, in part through redox-sensitive PI3K/Akt, which is inhibited by catalase overexpression. The relevant molecular mechanism remains unclear. Peroxisome proliferator-activated receptor gamma coactivator-1 α (PGC-1 α ) is reported to protect from oxidative stress by regulating expression of antioxidant enzymes such as catalase. We thus hypothesized that PGC-1 α may be important mediator for Ang II-induced H2O2 production and vascular hypertrophy. Here we show that Ang II stimulation increases serine phosphorylation of PGC-1 α (2.2 folds) with a peak at 15 min, which is inhibited by LY294002, a specific PI3 kinase inhibitor (98% decrease), and by Akt inhibitor-2/Triciribine (95% decrease). Ang II promotes PGC-1 α phosphorylation mainly at Ser 570 in an Akt-dependent manner. Ang II significantly suppresses Gal4-fused PGC-1 α transcriptional activity in a dose dependent manner, which is partially reversed by PI3K/Akt inhibition. Chromatin immunoprecipitation (ChIP) assay shows that PGC-1 α associates with the catalase promoter and this association is blocked by Ang II in a PI3K/Akt-dependent manner. Consistent with these results, Ang II stimulation time-dependently decreases endogenous catalase expression at both messenger RNA and protein levels. Ang II-induced downregulation of catalase at protein level at 24 hrs is prevented by Akt inhibitor (86%) and by overexpression of PGC-1 α S570A, an Akt phosphorylation site mutant, (75%). Moreover, overexpression of PGC-1 α S570A significantly inhibits Ang II-induced increase in H2O2 production (>80%) and leucine incorporation (>90%) as measured at 12 and 24 hrs, respectively. In summary, Akt-dependent serine phosphorylation of PGC-1 α by Ang II plays an important role for Ang II-induced downregulation of catalase, thereby increasing H2O2 production, which may contribute to ROS-dependent VSMC hypertrophy. These findings provide insight into a novel mechanisms by which Ang II promotes long-term H2O2 production to increase oxidative stress via targeting PGC-1alpha, and mediates metabolic abnormalities.

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