scholarly journals Essential roles of Gα12/13 signaling in distinct cell behaviors driving zebrafish convergence and extension gastrulation movements

2005 ◽  
Vol 169 (5) ◽  
pp. 777-787 ◽  
Author(s):  
Fang Lin ◽  
Diane S. Sepich ◽  
Songhai Chen ◽  
Jacek Topczewski ◽  
Chunyue Yin ◽  
...  
Keyword(s):  
Wnt Signaling ◽  
Cell Elongation ◽  
Dominant Negative ◽  
Embryonic Patterning ◽  
Mesodermal Cell ◽  
Cell Behaviors ◽  
Cellular Processes ◽  
Distinct Cell ◽  
Convergence And Extension ◽  
Modified Oligonucleotide

Gα12/13 have been implicated in numerous cellular processes, however, their roles in vertebrate gastrulation are largely unknown. Here, we show that during zebrafish gastrulation, suppression of both Gα12 and Gα13 signaling by overexpressing dominant negative proteins and application of antisense morpholino-modified oligonucleotide translation interference disrupted convergence and extension without changing embryonic patterning. Analyses of mesodermal cell behaviors revealed that Gα12/13 are required for cell elongation and efficient dorsalward migration during convergence independent of noncanonical Wnt signaling. Furthermore, Gα12/13 function cell-autonomously to mediate mediolateral cell elongation underlying intercalation during notochord extension, likely acting in parallel to noncanonical Wnt signaling. These findings provide the first evidence that Gα12 and Gα13 have overlapping and essential roles in distinct cell behaviors that drive vertebrate gastrulation.

scholarly journals Cooperation of polarized cell intercalations drives convergence and extension of presomitic mesoderm during zebrafish gastrulation

2008 ◽  
Vol 180 (1) ◽  
pp. 221-232 ◽  
Author(s):  
Chunyue Yin ◽  
Maria Kiskowski ◽  
Philippe-Alexandre Pouille ◽  
Emmanuel Farge ◽  
Lilianna Solnica-Krezel
Keyword(s):  
Wnt Signaling ◽  
Time Lapse ◽  
Presomitic Mesoderm ◽  
Mesodermal Cell ◽  
Cell Behaviors ◽  
Embryonic Tissues ◽  
Dorsal Mesoderm ◽  
Radial Cell ◽  
Convergence And Extension ◽  
Cell Layers

During vertebrate gastrulation, convergence and extension (C&E) movements narrow and lengthen the embryonic tissues, respectively. In zebrafish, regional differences of C&E movements have been observed; however, the underlying cell behaviors are poorly understood. Using time-lapse analyses and computational modeling, we demonstrate that C&E of the medial presomitic mesoderm is achieved by cooperation of planar and radial cell intercalations. Radial intercalations preferentially separate anterior and posterior neighbors to promote extension. In knypek;trilobite noncanonical Wnt mutants, the frequencies of cell intercalations are altered and the anteroposterior bias of radial intercalations is lost. This provides evidence for noncanonical Wnt signaling polarizing cell movements between different mesodermal cell layers. We further show using fluorescent fusion proteins that during dorsal mesoderm C&E, the noncanonical Wnt component Prickle localizes at the anterior cell edge, whereas Dishevelled is enriched posteriorly. Asymmetrical localization of Prickle and Dishevelled to the opposite cell edges in zebrafish gastrula parallels their distribution in fly, and suggests that noncanonical Wnt signaling defines distinct anterior and posterior cell properties to bias cell intercalations.

scholarly journals Glucocorticoid Receptor β (GRβ): Beyond Its Dominant-Negative Function

2021 ◽  
Vol 22 (7) ◽  
pp. 3649
Author(s):  
Patricia Ramos-Ramírez ◽  
Omar Tliba
Keyword(s):  
Current Knowledge ◽  
Inflammatory Diseases ◽  
Cell Communication ◽  
Cell Types ◽  
The Body ◽  
Dominant Negative ◽  
Negative Effects ◽  
Independent Manner ◽  
Distinct Cell ◽  
Induced Apoptosis

Glucocorticoids (GCs) act via the GC receptor (GR), a receptor ubiquitously expressed in the body where it drives a broad spectrum of responses within distinct cell types and tissues, which vary in strength and specificity. The variability of GR-mediated cell responses is further extended by the existence of GR isoforms, such as GRα and GRβ, generated through alternative splicing mechanisms. While GRα is the classic receptor responsible for GC actions, GRβ has been implicated in the impairment of GRα-mediated activities. Interestingly, in contrast to the popular belief that GRβ actions are restricted to its dominant-negative effects on GRα-mediated responses, GRβ has been shown to have intrinsic activities and “directly” regulates a plethora of genes related to inflammatory process, cell communication, migration, and malignancy, each in a GRα-independent manner. Furthermore, GRβ has been associated with increased cell migration, growth, and reduced sensitivity to GC-induced apoptosis. We will summarize the current knowledge of GRβ-mediated responses, with a focus on the GRα-independent/intrinsic effects of GRβ and the associated non-canonical signaling pathways. Where appropriate, potential links to airway inflammatory diseases will be highlighted.

scholarly journals Chemogenetic Tools for Causal Cellular and Neuronal Biology

2018 ◽  
Vol 98 (1) ◽  
pp. 391-418 ◽  
Author(s):  
Deniz Atasoy ◽  
Scott M. Sternson
Keyword(s):  
G Protein ◽  
Ex Vivo ◽  
Cell Types ◽  
Cell Populations ◽  
Specific Cell ◽  
Cellular Processes ◽  
Distinct Cell ◽  
G Protein Coupled ◽  
Pharmacological Control

Chemogenetic technologies enable selective pharmacological control of specific cell populations. An increasing number of approaches have been developed that modulate different signaling pathways. Selective pharmacological control over G protein-coupled receptor signaling, ion channel conductances, protein association, protein stability, and small molecule targeting allows modulation of cellular processes in distinct cell types. Here, we review these chemogenetic technologies and instances of their applications in complex tissues in vivo and ex vivo.

Characterization of a dominant negativeC. elegansTwist mutant protein with implications for human Saethre-Chotzen syndrome

Development ◽  
2002 ◽  
Vol 129 (11) ◽  
pp. 2761-2772
Author(s):  
Ann K. Corsi ◽  
Thomas M. Brodigan ◽  
Erik M. Jorgensen ◽  
Michael Krause
Keyword(s):  
Dna Binding ◽  
Binding Activity ◽  
Binding Domain ◽  
Dominant Negative ◽  
Mutant Protein ◽  
Dna Binding Domain ◽  
Mesodermal Cell ◽  
C Elegans ◽  
Dna Binding Activity ◽  
A Charge

Twist is a transcription factor that is required for mesodermal cell fates in all animals studied to date. Mutations of this locus in humans have been identified as the cause of the craniofacial disorder Saethre-Chotzen syndrome. The Caenorhabditis elegans Twist homolog is required for the development of a subset of the mesoderm. A semidominant allele of the gene that codes for CeTwist, hlh-8, has defects that occur earlier in the mesodermal lineage than a previously studied null allele of the gene. The semidominant allele has a charge change (E29K) in the basic DNA-binding domain of CeTwist. Surprisingly, the mutant protein retains DNA-binding activity as both a homodimer and a heterodimer with its partner E/Daughterless (CeE/DA). However, the mutant protein blocks the activation of the promoter of a target gene. Therefore, the mutant CeTwist may cause cellular defects as a dominant negative protein by binding to target promoters as a homo- or heterodimer and then blocking transcription. Similar phenotypes as those caused by the E29K mutation were observed when amino acid substitutions in the DNA-binding domain that are associated with the human Saethre-Chotzen syndrome were engineered into the C. elegans protein. These data suggest that Saethre-Chotzen syndrome may be caused, in some cases, by dominant negative proteins, rather than by haploinsufficiency of the locus.

scholarly journals Wnt canonical pathway activates macropinocytosis and lysosomal degradation of extracellular proteins

2019 ◽  
Vol 116 (21) ◽  
pp. 10402-10411 ◽  
Author(s):  
Nydia Tejeda-Muñoz ◽  
Lauren V. Albrecht ◽  
Maggie H. Bui ◽  
Edward M. De Robertis
Keyword(s):  
Wnt Signaling ◽  
Cancer Progression ◽  
Glycogen Synthase ◽  
Extracellular Fluid ◽  
Multivesicular Body ◽  
Extracellular Proteins ◽  
Dominant Negative ◽  
Canonical Wnt Signaling ◽  
Vacuolar Protein ◽  
Canonical Wnt

Canonical Wnt signaling is emerging as a major regulator of endocytosis. Wnt treatment markedly increased the endocytosis and degradation in lysosomes of BSA. In this study, we report that in addition to receptor-mediated endocytosis, Wnt also triggers the intake of large amounts of extracellular fluid by macropinocytosis, a nonreceptor-mediated actin-driven process. Macropinocytosis induction is rapid and independent of protein synthesis. In the presence of Wnt, large amounts of nutrient-rich packages such as proteins and glycoproteins were channeled into lysosomes after fusing with smaller receptor-mediated vesicles containing glycogen synthase kinase 3 (GSK3) and protein arginine ethyltransferase 1 (PRMT1), an enzyme required for canonical Wnt signaling. Addition of Wnt3a, as well as overexpression of Disheveled (Dvl), Frizzled (Fz8), or dominant-negative Axin induced endocytosis. Depletion of the tumor suppressors adenomatous polyposis coli (APC) or Axin dramatically increased macropinocytosis, defined by incorporation of the high molecular weight marker tetramethylrhodamine (TMR)-dextran and its blockage by the Na+/H+ exchanger ethylisopropyl amiloride (EIPA). Macropinocytosis was blocked by dominant-negative vacuolar protein sorting 4 (Vps4), indicating that the Wnt pathway is dependent on multivesicular body formation, a process called microautophagy. SW480 colorectal cancer cells displayed constitutive macropinocytosis and increased extracellular protein degradation in lysosomes, which were suppressed by restoring full-length APC. Accumulation of the transcriptional activator β-catenin in the nucleus of SW480 cells was inhibited by methyltransferase inhibition, EIPA, or the diuretic amiloride. The results indicate that Wnt signaling switches metabolism toward nutrient acquisition by engulfment of extracellular fluids and suggest possible treatments for Wnt-driven cancer progression.

scholarly journals The PRH/Hex repressor protein causes nuclear retention of Groucho/TLE co-repressors

2008 ◽  
Vol 417 (1) ◽  
pp. 121-132 ◽  
Author(s):  
Cecile Desjobert ◽  
Peter Noy ◽  
Tracey Swingler ◽  
Hannah  Williams ◽  
Kevin Gaston ◽  
...  
Keyword(s):  
Transcriptional Repression ◽  
Dominant Negative ◽  
Vertebrate Development ◽  
Nuclear Retention ◽  
Subnuclear Localization ◽  
Cellular Processes ◽  
Haematopoietic Cells ◽  
Repressor Proteins ◽  
Homeobox Protein ◽  
Important Regulator

The PRH (proline-rich homeodomain) [also known as Hex (haematopoietically expressed homeobox)] protein is a transcription factor that functions as an important regulator of vertebrate development and many other processes in the adult including haematopoiesis. The Groucho/TLE (transducin-like enhancer) family of co-repressor proteins also regulate development and modulate the activity of many DNA-binding transcription factors during a range of diverse cellular processes including haematopoiesis. We have shown previously that PRH is a repressor of transcription in haematopoietic cells and that an Eh-1 (Engrailed homology) motif present within the N-terminal transcription repression domain of PRH mediates binding to Groucho/TLE proteins and enables co-repression. In the present study we demonstrate that PRH regulates the nuclear retention of TLE proteins during cellular fractionation. We show that transcriptional repression and the nuclear retention of TLE proteins requires PRH to bind to both TLE and DNA. In addition, we characterize a trans-dominant-negative PRH protein that inhibits wild-type PRH activity by sequestering TLE proteins to specific subnuclear domains. These results demonstrate that transcriptional repression by PRH is dependent on TLE availability and suggest that subnuclear localization of TLE plays an important role in transcriptional repression by PRH.

Flt3 Internal Tandem Duplications Cooperate with Wnt Signaling in Leukemic Signal Transduction.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 822-822
Author(s):  
Lara Tickenbrock ◽  
Joachim Schwable ◽  
Markus Wiedehage ◽  
Bjoern Steffen ◽  
Chunaram Choudhary ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Wnt Signaling ◽  
Fusion Proteins ◽  
Transcriptional Activity ◽  
Dominant Negative ◽  
Cell Surface Receptor ◽  
Hematopoietic Stem ◽  
Cell Fate Decisions ◽  
Wnt Proteins ◽  
Tandem Duplications

Abstract Flt3 internal tandem duplications cooperate with Wnt signaling in leukemic signal transduction Lara Tickenbrock, Joachim Schwable, Markus Wiedehage, Bjoern Steffen, Chunaram Choudhary, Wolfgang E. Berdel, Carsten Muller-Tidow and Hubert Serve Department of Medicine, Hematology and Oncology, University of Muenster, D-48149 Muenster, Germany The type III receptor tyrosine kinase (RTK) Flt3 plays an important role in survival and proliferation of hematopoietic progenitor cells. Somatic mutations of Flt3 consisting of internal tandem duplications (ITD) occur in 25% of patients with acute myeloid leukemia (AML), and are associated with a poor prognosis. They result in Flt3-ligand (FL) independent kinase activation of Flt3. The Wnt signal transduction pathway has recently been implicated to be an important regulator of early hematopoietic stem cell fate decisions. Also, we previously showed that activation of Wnt-dependent Tcf transcriptional activity is induced by the leukemia-associated fusion proteins PML-RAR? and AML1-ETO. Here, we show that Flt3-ITD mutations enhance basal and Wnt3a-stimulated Tcf activity in myeloid cells. Microarray experiments analyzing Flt3-ITD target genes in 32D cells revealed up to 8-fold induction of Frizzled-4, a cell surface receptor for Wnt proteins, by Flt3-ITD mutations. This could be verified by real-time RT-PCR and Western Blot analyses. In functional analyses, we explored the synergism of Flt3-ITD and the activation of Wnt signaling. Flt3-ITD mutations induced the accumulation of ?-Catenin and TCF-dependent transcriptional activity. Also, the presence of Flt3-ITD highly sensitized cells for ?-Catenin-induction by the Wnt3a. Wnt3a incubation enhanced 32D cell proliferation in the presence of activated Flt3 receptors. More importantly, Flt3-ITD-mediated clonogenic growth highly depended on the activity of Tcf transcription factors, since transient transfection of Flt3-ITD cells with dominant negative TCF4 almost abolished 32D cell colony growth. Our results indicate that Flt3-ITD mutations mediate their leukemogenic effects in part through the activation of Wnt-dependent signaling pathways, possibly defining this signal system as a converging point of leukemogenic events elicited by Flt3-mutations and leukemia-associated fusion proteins.

scholarly journals Extracellular Signal-Regulated Kinase 1c (ERK1c), a Novel 42-Kilodalton ERK, Demonstrates Unique Modes of Regulation, Localization, and Function

2004 ◽  
Vol 24 (22) ◽  
pp. 10000-10015 ◽  
Author(s):  
Daniel M. Aebersold ◽  
Yoav D. Shaul ◽  
Yuval Yung ◽  
Nirit Yarom ◽  
Zhong Yao ◽  
...  
Keyword(s):  
Cell Density ◽  
Differential Regulation ◽  
Dominant Negative ◽  
Signaling Specificity ◽  
Cellular Processes ◽  
Extracellular Signal ◽  
Extracellular Stimuli ◽  
Golgi Fragmentation ◽  
And Function ◽  
Rats And Mice

ABSTRACT Extracellular signal-regulated kinases (ERKs) are signaling molecules that regulate many cellular processes. We have previously identified an alternatively spliced 46-kDa form of ERK1 that is expressed in rats and mice and named ERK1b. Here we report that the same splicing event in humans and monkeys causes, due to sequence differences in the inserted introns, the production of an ERK isoform that migrates together with the 42-kDa ERK2. Because of the differences of this isoform from ERK1b, we named it ERK1c. We found that its expression levels are about 10% of ERK1. ERK1c seems to be expressed in a wide variety of tissues and cells. Its activation by MEKs and inactivation by phosphatases are slower than those of ERK1, which is probably the reason for its differential regulation in response to extracellular stimuli. Unlike ERK1, ERK1c undergoes monoubiquitination, which is increased with elevated cell density concomitantly with accumulation of ERK1c in the Golgi apparatus. Elevated cell density also causes enhanced Golgi fragmentation, which is facilitated by overexpression of native ERK1c and is prevented by dominant-negative ERK1c, indicating that ERK1c mediates cell density-induced Golgi fragmentation. The differential regulation of ERK1c extends the signaling specificity of MEKs after stimulation by various extracellular stimuli.

scholarly journals Critical Activities of Rac1 and Cdc42Hs in Skeletal Myogenesis: Antagonistic Effects of JNK and p38 Pathways

2000 ◽  
Vol 11 (8) ◽  
pp. 2513-2528 ◽  
Author(s):  
Mayya Meriane ◽  
Pierre Roux ◽  
Michael Primig ◽  
Philippe Fort ◽  
Cécile Gauthier-Rouvière
Keyword(s):  
Troponin T ◽  
Critical Role ◽  
Myoblast Fusion ◽  
Dominant Negative ◽  
Rho Proteins ◽  
Inhibitory Effects ◽  
Jnk Pathway ◽  
Antagonistic Effects ◽  
Cellular Processes ◽  
Rho Family

The Rho family of GTP-binding proteins plays a critical role in a variety of cellular processes, including cytoskeletal reorganization and activation of kinases such as p38 and C-jun N-terminal kinase (JNK) MAPKs. We report here that dominant negative forms of Rac1 and Cdc42Hs inhibit the expression of the muscle-specific genes myogenin, troponin T, and myosin heavy chain in L6 and C2 myoblasts. Such inhibition correlates with decreased p38 activity. Active RhoA, RhoG, Rac1, and Cdc42Hs also prevent myoblast-to-myotube transition but affect distinct stages: RhoG, Rac1, and Cdc42Hs inhibit the expression of all muscle-specific genes analyzed, whereas active RhoA potentiates their expression but prevents the myoblast fusion process. We further show by two different approaches that the inhibitory effects of active Rac1 and Cdc42Hs are independent of their morphogenic activities. Rather, myogenesis inhibition is mediated by the JNK pathway, which also leads to a cytoplasmic redistribution of Myf5. We propose that although Rho proteins are required for the commitment of myogenesis, they differentially influence this process, positively for RhoA and Rac1/Cdc42Hs through the activation of the SRF and p38 pathways, respectively, and negatively for Rac1/Cdc42Hs through the activation of the JNK pathway.

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