scholarly journals CLAVATA3 mediated simultaneous control of transcriptional and post-translational processes provides robustness to the WUSCHEL gradient

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Alexander Plong ◽  
Kevin Rodriguez ◽  
Mark Alber ◽  
Weitao Chen ◽  
G. Venugopala Reddy
Keyword(s):  
Translational Control ◽  
Transcriptional Repression ◽  
De Novo ◽  
Dual Control ◽  
Receptor Kinase ◽  
Unstable System ◽  
Simultaneous Control ◽  
Seamless Connection ◽  
Nuclear Levels ◽  
Receptor Kinase Signaling

AbstractRegulation of the homeodomain transcription factor WUSCHEL concentration is critical for stem cell homeostasis in Arabidopsis shoot apical meristems. WUSCHEL regulates the transcription of CLAVATA3 through a concentration-dependent activation-repression switch. CLAVATA3, a secreted peptide, activates receptor kinase signaling to repress WUSCHEL transcription. Considering the revised regulation, CLAVATA3 mediated repression of WUSCHEL transcription alone will lead to an unstable system. Here we show that CLAVATA3 signaling regulates nuclear-cytoplasmic partitioning of WUSCHEL to control nuclear levels and its diffusion into adjacent cells. Our work also reveals that WUSCHEL directly interacts with EXPORTINS via EAR-like domain which is also required for destabilizing WUSCHEL in the cytoplasm. We develop a combined experimental and computational modeling approach that integrates CLAVATA3-mediated transcriptional repression of WUSCHEL and post-translational control of nuclear levels with the WUSCHEL concentration-dependent regulation of CLAVATA3. We show that the dual control by the same signal forms a seamless connection between de novo WUSCHEL synthesis and sub-cellular partitioning in providing robustness to the WUSCHEL gradient.

scholarly journals A conserved regulatory module regulates receptor kinase signaling in immunity and development

2021 ◽  
Author(s):  
Thomas A. DeFalco ◽  
Pauline Anne ◽  
Sean R. James ◽  
Andrew Willoughby ◽  
Oliver Johanndrees ◽  
...  
Keyword(s):  
Cell Surface ◽  
Cellular Responses ◽  
Receptor Signaling ◽  
Receptor Kinase ◽  
Surface Receptors ◽  
Receptor Complexes ◽  
Regulatory Circuit ◽  
Regulatory Module ◽  
Molecular Patterns ◽  
Receptor Kinase Signaling

ABSTRACTLigand recognition by cell-surface receptors underlies development and immunity in both animals and plants. Modulating receptor signaling is critical for appropriate cellular responses but the mechanisms ensuring this are poorly understood. Here, we show that signaling by plant receptors for pathogen-associated molecular patterns (PAMPs) in immunity and CLAVATA3/EMBRYO SURROUNDING REGION-RELATED peptides (CLEp) in development employ a similar regulatory module. In the absence of ligand, signaling is dampened through association with specific type-2C protein phosphatases (PP2Cs). Upon activation, PAMP and CLEp receptors phosphorylate divergent cytosolic kinases, which, in turn, phosphorylate the phosphatases, thereby promoting their release from the receptor complexes. Our work reveals a regulatory circuit shared between immune and developmental receptor signaling, which may have broader important implications for plant receptor kinase-mediated signaling in general.

scholarly journals Reorganization of budding yeast cytoplasm upon energy depletion

2020 ◽  
Vol 31 (12) ◽  
pp. 1232-1245 ◽  
Author(s):  
Guendalina Marini ◽  
Elisabeth Nüske ◽  
Weihua Leng ◽  
Simon Alberti ◽  
Gaia Pigino
Keyword(s):  
Translational Control ◽  
De Novo ◽  
Budding Yeast ◽  
Energy Depletion

Yeast responds to energy depletion with a rapid cytoplasmic reorganization that includes cytosol compaction and de novo formation of membraneless compartments. The reversible polymerization of eIF2B into filamentous assemblies suggests a mechanism of translational control that allows cells to move quickly back and forth between response states.

Molecular cloning of a centrin homolog from Marsilea vestita and evidence for its translational control during spermiogenesis

1999 ◽  
Vol 77 (2) ◽  
pp. 101-108 ◽  
Author(s):  
Peter E Hart ◽  
Stephen M Wolniak
Keyword(s):  
Translational Control ◽  
De Novo ◽  
Basal Bodies ◽  
Motile Cells ◽  
Marsilea Vestita ◽  
Stored Mrna ◽  
Eukaryotic Organisms ◽  
Alpha Amanitin ◽  
Made In

Spermiogenesis in the water fern Marsilea vestita is a process that reaches completion 11 h after dry microspores are immersed in an aqueous medium at 20°C. Each microspore produces 32 spermatozoids and each spermatozoid has a coiled cell body and approximately 140 cilia. The spermatids make basal bodies de novo, from a structure known as a blepharoplast. From the onset of development, the spores contain a large quantity of protein and stored mRNA. We have found previously that centrin, a protein involved in the function of microtubule organizing centers and present in association with basal bodies in motile cells, is made in large quantity approximately 4 h after the microspores are placed into liquid medium. In this paper, we show that a centrin cDNA (MvCen1) we isolated from M. vestita closely resembles centrin cDNAs from other eukaryotic organisms. MvCen1, synthesized in Escherichia coli as a GST-fusion protein, reacted with anti-centrin monoclonal antibodies on immunoblots. Northern blot analysis demonstrates that centrin mRNA is present in the dry microspore at the time of imbibition, at levels that remain constant over 10 h of development and are unaffected by treatment of spores with alpha-amanitin. The centrin transcripts, stored in dry microspores, cannot be translated in vitro for at least 30 min after imbibition.Key words: Marsilea vestita, spermatozoid, spermiogenesis, centrin, MTOC.

scholarly journals The KAP1 Corepressor Functions To Coordinate the Assembly of De Novo HP1-Demarcated Microenvironments of Heterochromatin Required for KRAB Zinc Finger Protein-Mediated Transcriptional Repression

2006 ◽  
Vol 26 (22) ◽  
pp. 8623-8638 ◽  
Author(s):  
Smitha P. Sripathy ◽  
Jessica Stevens ◽  
David C. Schultz
Keyword(s):  
Rna Polymerase Ii ◽  
Zinc Finger ◽  
Histone Modifications ◽  
Dna Sequences ◽  
Transcriptional Repression ◽  
Zinc Finger Protein ◽  
De Novo ◽  
Regulatory Sequences ◽  
Phd Finger ◽  
Finger Protein

ABSTRACT KAP1/TIF1β is proposed to be a universal corepressor protein for the KRAB zinc finger protein (KRAB-zfp) superfamily of transcriptional repressors. To characterize the role of KAP1 and KAP1-interacting proteins in transcriptional repression, we investigated the regulation of stably integrated reporter transgenes by hormone-responsive KRAB and KAP1 repressor proteins. Here, we demonstrate that depletion of endogenous KAP1 levels by small interfering RNA (siRNA) significantly inhibited KRAB-mediated transcriptional repression of a chromatin template. Similarly, reduction in cellular levels of HP1α/β/γ and SETDB1 by siRNA attenuated KRAB-KAP1 repression. We also found that direct tethering of KAP1 to DNA was sufficient to repress transcription of an integrated transgene. This activity is absolutely dependent upon the interaction of KAP1 with HP1 and on an intact PHD finger and bromodomain of KAP1, suggesting that these domains function cooperatively in transcriptional corepression. The achievement of the repressed state by wild-type KAP1 involves decreased recruitment of RNA polymerase II, reduced levels of histone H3 K9 acetylation and H3K4 methylation, an increase in histone occupancy, enrichment of trimethyl histone H3K9, H3K36, and histone H4K20, and HP1 deposition at proximal regulatory sequences of the transgene. A KAP1 protein containing a mutation of the HP1 binding domain failed to induce any change in the histone modifications associated with DNA sequences of the transgene, implying that HP1-directed nuclear compartmentalization is required for transcriptional repression by the KRAB/KAP1 repression complex. The combination of these data suggests that KAP1 functions to coordinate activities that dynamically regulate changes in histone modifications and deposition of HP1 to establish a de novo microenvironment of heterochromatin, which is required for repression of gene transcription by KRAB-zfps.

scholarly journals Emerging mechanisms to fine-tune receptor kinase signaling specificity

2020 ◽  
Vol 57 ◽  
pp. 41-51 ◽  
Author(s):  
Sergio Galindo-Trigo ◽  
Patrick Blümke ◽  
Rüdiger Simon ◽  
Melinka A Butenko
Keyword(s):  
Receptor Kinase ◽  
Kinase Signaling ◽  
Signaling Specificity ◽  
Receptor Kinase Signaling ◽  
Fine Tune

scholarly journals HERP, a Novel Heterodimer Partner of HES/E(spl) in Notch Signaling

2001 ◽  
Vol 21 (17) ◽  
pp. 6080-6089 ◽  
Author(s):  
Tatsuya Iso ◽  
Vittorio Sartorelli ◽  
Coralie Poizat ◽  
Simona Iezzi ◽  
Hung-Yi Wu ◽  
...  
Keyword(s):  
Dna Binding ◽  
Notch Signaling ◽  
Dna Sequences ◽  
Transcriptional Repression ◽  
De Novo ◽  
Single Cells ◽  
Binding Activity ◽  
Bhlh Protein ◽  
Helix Loop Helix ◽  
Dna Binding Activity

ABSTRACT HERP1 and -2 are members of a new basic helix-loop-helix (bHLH) protein family closely related to HES/E(spl), the only previously known Notch effector. Like that of HES, HERP mRNA expression is directly up-regulated by Notch ligand binding without de novo protein synthesis. HES and HERP are individually expressed in certain cells, but they are also coexpressed within single cells after Notch stimulation. Here, we show that HERP has intrinsic transcriptional repression activity. Transcriptional repression by HES/E(spl) entails the recruitment of the corepressor TLE/Groucho via a conserved WRPW motif, whereas unexpectedly the corresponding—but modified—tetrapeptide motif in HERP confers marginal repression. Rather, HERP uses its bHLH domain to recruit the mSin3 complex containing histone deacetylase HDAC1 and an additional corepressor, N-CoR, to mediate repression. HES and HERP homodimers bind similar DNA sequences, but with distinct sequence preferences, and they repress transcription from specific DNA binding sites. Importantly, HES and HERP associate with each other in solution and form a stable HES-HERP heterodimer upon DNA binding. HES-HERP heterodimers have both a greater DNA binding activity and a stronger repression activity than do the respective homodimers. Thus, Notch signaling relies on cooperation between HES and HERP, two transcriptional repressors with distinctive repression mechanisms which, either as homo- or as heterodimers, regulate target gene expression.

Glucocorticoids inhibit IL-1β-induced GM-CSF expression at multiple levels: roles for the ERK pathway and repression by MKP-1

2010 ◽  
Vol 427 (1) ◽  
pp. 113-124 ◽  
Author(s):  
Robert Newton ◽  
Elizabeth M. King ◽  
Wei Gong ◽  
Christopher F. Rider ◽  
Karl J. Staples ◽  
...  
Keyword(s):  
Gene Expression ◽  
Protein Synthesis ◽  
Transcriptional Repression ◽  
Actinomycin D ◽  
De Novo ◽  
A549 Cells ◽  
Mitogen Activated Protein Kinase ◽  
Erk Pathway ◽  
Gm Csf ◽  
Erk Phosphorylation

In the present study, IL (interleukin)-1β increased GM-CSF (granulocyte/macrophage colony-stimulating factor) expression from pulmonary A549 cells and primary HBE (human bronchial epithelial) cells. These responses were repressed by the glucocorticoid dexamethasone, allowing the use of A549 cells as a relevant model. IL-1β induced GM-CSF release into the culture medium by 6 h and in cell lysates (cytosolic) at 2 h. These effects were profoundly inhibited by dexamethasone, yet IL-1β-induced GM-CSF mRNA and unspliced nRNA (nuclear RNA; a surrogate of transcription rate) were modestly inhibited by dexamethasone at times up to 2 h. Although this indicates an effect on protein synthesis, actinomycin D chase experiments also indicated post-transcriptional repression by dexamethasone. Dexamethasone-dependent mRNA repression increased with time and was prevented by translational blockade. In addition, dexamethasone and the dissociated steroid RU24858 repressed GM-CSF release in an actinomycin D-sensitive manner, thereby implicating glucocorticoid-induced gene expression. At 2 h, IL-1β-induced expression of GM-CSF protein, but not mRNA, was sensitive to the MEK [MAPK (mitogen-activated protein kinase)/ERK (extracellular-signal-regulated kinase) kinase] inhibitors PD098059 and U0126. Although this indicates a role for the MEK/ERK pathway in GM-CSF translation, PD098059 subsequently destabilized GM-CSF mRNA. Dexamethasone and RU24858 both reduced IL-1β-induced ERK phosphorylation and increased MKP-1 (MAPK phosphatase-1) expression. Inhibition of ERK phosphorylation was reproduced by MKP-1 overexpression and prevented by MKP-1-targeting siRNA (small interfering RNA). Since MKP-1 prevented GM-CSF expression by transcriptional, post-transcriptional and translational processes, we propose that glucocorticoids induce MKP-1 expression to reduce both MEK/ERK activation and GM-CSF protein synthesis. Thus de novo gene expression, particularly of MKP-1, is involved in the repressive effects of glucocorticoids.

scholarly journals Organization of the Receptor-Kinase Signaling Array That RegulatesEscherichia coliChemotaxis

2002 ◽  
Vol 277 (39) ◽  
pp. 36748-36754 ◽  
Author(s):  
Mikhail N. Levit ◽  
Thorsten W. Grebe ◽  
Jeffry B. Stock
Keyword(s):  
Receptor Kinase ◽  
Kinase Signaling ◽  
Receptor Kinase Signaling
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