13,395 results match your criteria activity xenopus


Bicc1 and Dicer regulate left-right patterning through post-transcriptional control of the Nodal inhibitor Dand5.

Nat Commun 2021 Sep 16;12(1):5482. Epub 2021 Sep 16.

University of Hohenheim, Institute of Biology, Department of Zoology, Stuttgart, Germany.

Rotating cilia at the vertebrate left-right organizer (LRO) generate an asymmetric leftward flow, which is sensed by cells at the left LRO margin. Ciliary activity of the calcium channel Pkd2 is crucial for flow sensing. How this flow signal is further processed and relayed to the laterality-determining Nodal cascade in the left lateral plate mesoderm (LPM) is largely unknown. Read More

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September 2021

Imaging Structural and Functional Dynamics in Neurons.

Authors:
Hollis T Cline

Cold Spring Harb Protoc 2021 Sep 16. Epub 2021 Sep 16.

Department of Neuroscience, Dorris Neuroscience Center, The Scripps Research Center, La Jolla, California 92039, USA

In vivo time-lapse imaging has been a fruitful approach to identify structural and functional changes in the nervous system in tadpoles and adult frogs. Structural imaging studies have identified fundamental aspects of brain connectivity, development, plasticity, and disease and have been instrumental in elucidating mechanisms regulating these events in vivo. Similarly, assessment of nervous system function using dynamic changes in calcium signals as a proxy for neuronal activity has demonstrated principles of neuron and circuit function and principles of information organization and transfer within the brain of living animals. Read More

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September 2021

Transmembrane H fluxes and the regulation of neural induction in .

Zygote 2021 Sep 17:1-12. Epub 2021 Sep 17.

Division of Life Science and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Hong Kong, China.

It has previously been reported that in ex vivo planar explants prepared from Xenopus laevis embryos, the intracellular pH (pHi) increases in cells of the dorsal ectoderm from stage 10.5 to 11.5 (i. Read More

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September 2021

Design, Synthesis, and Activity of an α-Conotoxin LtIA Fluorescent Analogue.

ACS Chem Neurosci 2021 Sep 15. Epub 2021 Sep 15.

Key Laboratory of Tropical Biological Resources of Ministry of Education, School of Life and Pharmaceutical Sciences, Hainan University, Haikou 570228, China.

Nicotinic acetylcholine receptors (nAChRs) are essential pentameric ligand-gated ion channels that are distributed throughout the central and peripheral nervous systems and non-neuronal tissues in mammalian species that play critical roles in a variety of neural and mental activities. The α3β2 nAChR subtype participates in pain, addiction to nicotine, and other neurophysiological and pathological activities. Owing to the lack of highly selective pharmacological tools targeting α3β2, related research on its tissue distribution and function has been hindered. Read More

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September 2021

Two Calcium-Dependent Protein Kinases Enhance Maize Drought Tolerance by Activating Anion Channel ZmSLAC1 in Guard Cells.

Plant Biotechnol J 2021 Sep 9. Epub 2021 Sep 9.

State Key Laboratory of Plant Physiology and Biochemistry (SKLPPB), College of Biological Sciences, China Agricultural University, Beijing, 100193, China.

Stomatal closure is an important process to prevent water loss in plants response to drought stress, which is finely modulated by ion channels together with their regulators in guard cells, especially the S-type anion channel AtSLAC1 in Arabidopsis. However, the functional characterization and regulation analyses of anion channels in gramineous crops, such as in maize guard cells are still limited. In this study, we identified an S-type anion channel ZmSLAC1 that was preferentially expressed in maize guard cells and involved in stomatal closure under drought stress. Read More

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September 2021

Biochemical and developmental effects of thyroid and anti-thyroid drugs on different early life stages of Xenopus laevis.

Environ Toxicol Pharmacol 2021 Oct 4;87:103738. Epub 2021 Sep 4.

Department of Biology, Faculty of Arts and Science, Inonu University, 44280, Malatya, Turkey. Electronic address:

The effects of two drugs containing the synthetic thyroid hormone levothyroxine (LEV) and an anti-thyroid drug containing propylthiouracil (PTU) on the three early life stages of Xenopus laevis were evaluated with the Frog Embryo Teratogenesis Assay-Xenopus, Tadpole Toxicity Test, and Amphibian Metamorphosis Assay using biochemical and morphological markers. Tested drugs caused more effective growth retardation in stage 8 embryos than stage 46 tadpoles. Significant inhibition of biomarker enzymes has been identified in stage 46 tadpoles for both drugs. Read More

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October 2021

Sub-lethal exposure to malaria vector control pesticides causes alterations in liver metabolomics and behaviour of the African clawed frog (Xenopus laevis).

Comp Biochem Physiol C Toxicol Pharmacol 2021 Sep 4:109173. Epub 2021 Sep 4.

Water Research Group, Unit for Environmental Sciences and Management, North-West University, Potchefstroom, South Africa.

In this study we explore the sub-lethal effects of two malaria vector control pesticides, deltamethrin and dichlorodiphenyltrichloroethane (DDT), on Xenopus laevis by incorporating different levels of biological organisation. Pesticide accumulation in frog tissue was measured alongside liver metabolomics and individual swimming behaviour to assess whether changes presented at these different levels, and if such changes could be linked between levels. Results showed evidence of concentration dependent accumulation of DDT and its metabolites, but no measurable accumulation of deltamethrin in adult X. Read More

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September 2021

Noncanonical Notch signals have opposing roles during cardiac development.

Biochem Biophys Res Commun 2021 Sep 2;577:12-16. Epub 2021 Sep 2.

Division of Cardiology, Department of Medicine, Johns Hopkins University, Baltimore, MD, USA; Heart and Vascular Institute, Cellular and Molecular Medicine, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Biomedical Engineering, Department of Cell Biology, Johns Hopkins University, Baltimore, MD, USA. Electronic address:

The Notch pathway is an ancient intercellular signaling system with crucial roles in numerous cell-fate decision processes across species. While the canonical pathway is activated by ligand-induced cleavage and nuclear localization of membrane-bound Notch, Notch can also exert its activity in a ligand/transcription-independent fashion, which is conserved in Drosophila, Xenopus, and mammals. However, the noncanonical role remains poorly understood in in vivo processes. Read More

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September 2021

A D-pinitol transporter, LjPLT11, regulates plant growth and nodule development in Lotus japonicus.

J Exp Bot 2021 Aug 30. Epub 2021 Aug 30.

Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement & Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China.

Polyol transporters (PLTs) have been functionally characterized in yeast and Xenopus laevis oocytes as H +-symporters with broad substrate specificity, but little is known about their physiological roles in planta. To extend this knowledge we investigated roles of LjPLT11 in Lotus japonicus-Mesorhizobium symbiosis. Functional analyses of the LjPLT11 in yeast characterized this protein as an energy-independent transporter of xylitol, two O-methyl inositols, xylose and galactose. Read More

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Crystal structure of aspartyl dipeptidase from Xenopus laevis revealed ligand binding induced loop ordering and catalytic triad assembly.

Proteins 2021 Aug 25. Epub 2021 Aug 25.

Beamline Development and Application Section, Bhabha Atomic Research Centre, Mumbai, India.

Gene encoding aspartyl dipeptidase from Xenopus levies (PepExl) is upregulated by thyroid hormone and is proposed to play a significant role in resorption of tadpole tail during metamorphosis. However, the importance of peptidase activity for the resorption of the tail remain elusive. Here we report the crystal structures of first eukaryotic S51 peptidase, PepExl, in its ligand-free and Asp-bound states at 1. Read More

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Progeny of Xenopus laevis from altitudinal extremes display adaptive physiological performance.

J Exp Biol 2021 04 15;224(7). Epub 2021 Apr 15.

Centre for Invasion Biology, Department of Botany and Zoology, Stellenbosch University, Stellenbosch, 7602 South Africa.

Environmental temperature variation generates adaptive phenotypic differentiation in widespread populations. We used a common garden experiment to determine whether offspring with varying parental origins display adaptive phenotypic variation related to different thermal conditions experienced in parental environments. We compared burst swimming performance and critical thermal limits of African clawed frog (Xenopus laevis) tadpoles bred from adults captured at high (∼2000 m above sea level) and low (∼ 5 m above sea level) altitudes. Read More

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Neonatal Na 1.5: Pharmacological distinctiveness of a cancer-related voltage-gated sodium channel splice variant.

Br J Pharmacol 2021 Aug 19. Epub 2021 Aug 19.

Imperial College London, Department of Life Sciences, Neuroscience Solutions to Cancer Research Group, London, UK.

Background And Purpose: Voltage-gated sodium (Na ) channels are expressed de novo in carcinomas where their activity promotes invasiveness. Breast and colon cancer cells express the neonatal splice variant of Na 1.5 (nNa 1. Read More

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Genetic and Physiological Effects of Insulin on Human Urate Homeostasis.

Front Physiol 2021 2;12:713710. Epub 2021 Aug 2.

Renal Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States.

Insulin and hyperinsulinemia reduce renal fractional excretion of urate (FeU) and play a key role in the genesis of hyperuricemia and gout, via uncharacterized mechanisms. To explore this association further we studied the effects of genetic variation in insulin-associated pathways on serum urate (SU) levels and the physiological effects of insulin on urate transporters. We found that urate-associated variants in the human insulin (INS), insulin receptor (INSR), and insulin receptor substrate-1 (IRS1) loci associate with the expression of the insulin-like growth factor 2, IRS1, INSR, and ZNF358 genes; additionally, we found genetic interaction between and the three loci, most evident in women. Read More

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Cy3-RgIA-5727 Labels and Inhibits α9-Containing nAChRs of Cochlear Hair Cells.

Front Cell Neurosci 2021 23;15:697560. Epub 2021 Jul 23.

Department of Biology, University of Utah, Salt Lake City, UT, United States.

Efferent cholinergic neurons inhibit sensory hair cells of the vertebrate inner ear through the combined action of calcium-permeable α9α10-containing nicotinic acetylcholine receptors (nAChRs) and associated calcium-dependent potassium channels. The venom of cone snails is a rich repository of bioactive peptides, many with channel blocking activities. The conopeptide analog, RgIA-5474, is a specific and potent antagonist of α9α10-containing nAChRs. Read More

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SnoRNA guide activities - real and ambiguous.

RNA 2021 Aug 12. Epub 2021 Aug 12.

Carnegie Institution for Science, Department of Embryology.

In eukaryotes, rRNAs and spliceosomal snRNAs are heavily modified posttranscriptionally. Pseudouridylation and 2'-O-methylation are the most abundant types of RNA modifications. They are mediated by modification guide RNAs, also known as small nucleolar (sno)RNAs and small Cajal body-specific (sca)RNAs. Read More

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Influence of Sox protein SUMOylation on neural development and regeneration.

Authors:
Kun-Che Chang

Neural Regen Res 2022 Mar;17(3):477-481

Department of Ophthalmology, Louis J. Fox Center for Vision Restoration, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.

SRY-related HMG-box (Sox) transcription factors are known to regulate central nervous system development and are involved in several neurological diseases. Post-translational modification of Sox proteins is known to alter their functions in the central nervous system. Among the different types of post-translational modification, small ubiquitin-like modifier (SUMO) modification of Sox proteins has been shown to modify their transcriptional activity. Read More

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Analysis of Transforming Growth Factor ß Family Cleavage Products Secreted Into the Blastocoele of Xenopus laevis Embryos.

J Vis Exp 2021 Jul 21(173). Epub 2021 Jul 21.

Departments of Neurobiology and Department of Internal Medicine, Division of Hematology and Hematologic Malignancies, University of Utah, School of Medicine;

The two arms of the Transforming Growth Factor ß (Tgfß) superfamily, represented by Tgfß/Nodal or Bone morphogenetic protein (Bmp) ligands, respectively, play essential roles in embryonic development and adult homeostasis. Members of the Tgfß family are made as inactive precursors that dimerize and fold within the endoplasmic reticulum. The precursor is subsequently cleaved into ligand and prodomain fragments. Read More

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Modulation of Intracellular ROS and Senescence-Associated Phenotypes of Oocytes and Eggs by Selective Antioxidants.

Antioxidants (Basel) 2021 Jul 1;10(7). Epub 2021 Jul 1.

Laboratory of Cell Signaling and Development, Faculty of Life Sciences, Kyoto Sangyo University, Kyoto 603-8555, Japan.

Aging of oocytes and eggs diminishes their reproductive and developmental potential. It has been demonstrated previously that reactive oxygen species (ROS) contribute to accelerated aging of various cells. In the present study, we measured intracellular levels of ROS and investigated effects of several selective antioxidants (AOXs) on the viability and functional activity of aging oocytes and eggs of the African clawed frog . Read More

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The expression of constitutively active CPK3 impairs potassium uptake and transport in Arabidopsis under low K stress.

Cell Calcium 2021 09 19;98:102447. Epub 2021 Jul 19.

State Key Laboratory of Subtropical Silviculture, School of Forestry and Biotechnology, Zhejiang A & F University, Hangzhou, Zhejiang 311300, China. Electronic address:

Potassium (K) is a vital cation and is involved in multiple physiological functions in plants. K uptake from outer medium by roots is a tightly regulated process and is mainly carried out by two high affinity K transport proteins AKT1 and HAK5. It has been shown that calcium (Ca) signaling plays important roles in the regulation of K transport in plants. Read More

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September 2021

The Amyloid Precursor Protein C99 Fragment Modulates Voltage-Gated Potassium Channels.

Cell Physiol Biochem 2021 Jul;55(S3):157-170

Bioelectricity Laboratory, Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, CA, USA,

Background/aims: The Amyloid Precursor Protein (APP) is involved in the regulation of multiple cellular functions via protein-protein interactions and has been most studied with respect to Alzheimer's disease (AD). Abnormal processing of the single transmembrane-spanning C99 fragment of APP contributes to the formation of amyloid plaques, which are causally related to AD. Pathological C99 accumulation is thought to associate with early cognitive defects in AD. Read More

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Identification of Dihydromyricetin and Metabolites in Serum and Brain Associated with Acute Anti-Ethanol Intoxicating Effects in Mice.

Int J Mol Sci 2021 Jul 12;22(14). Epub 2021 Jul 12.

Department of Medicinal Chemistry, Ernest Mario School of Pharmacy, Rutgers University, Piscataway, NJ 08854, USA.

Dihydromyricetin is a natural bioactive flavonoid with unique GABA receptor activity with a putative mechanism of action to reduce the intoxication effects of ethanol. Although dihydromyricetin's poor oral bioavailability limits clinical utility, the promise of this mechanism for the treatment of alcohol use disorder warrants further investigation into its specificity and druggable potential. These experiments investigated the bioavailability of dihydromyricetin in the brain and serum associated with acute anti-intoxicating effects in C57BL/6J mice. Read More

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Role of matrix metalloproteinase-9 in neurodevelopmental deficits and experience-dependent plasticity in .

Elife 2021 07 20;10. Epub 2021 Jul 20.

Department of Neuroscience, Brown University, Providence, United States.

Matrix metalloproteinase-9 (MMP-9) is a secreted endopeptidase targeting extracellular matrix proteins, creating permissive environments for neuronal development and plasticity. Developmental dysregulation of MMP-9 may also lead to neurodevelopmental disorders (ND). Here, we test the hypothesis that chronically elevated MMP-9 activity during early neurodevelopment is responsible for neural circuit hyperconnectivity observed in tadpoles after early exposure to valproic acid (VPA), a known teratogen associated with ND in humans. Read More

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Spatio-temporal expression pattern and role of the tight junction protein MarvelD3 in pancreas development and function.

Sci Rep 2021 Jul 15;11(1):14519. Epub 2021 Jul 15.

Cell Biology Unit, de Duve Institute, UCLouvain, Woluwe, Belgium.

Tight junction complexes are involved in the establishment and maintenance of cell polarity and the regulation of signalling pathways, controlling biological processes such as cell differentiation and cell proliferation. MarvelD3 is a tight junction protein expressed in adult epithelial and endothelial cells. In Xenopus laevis, MarvelD3 morphants present differentiation defects of several ectodermal derivatives. Read More

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[2.2]Paracyclophane-Based TCN-201 Analogs as GluN2A-Selective NMDA Receptor Antagonists.

ChemMedChem 2021 Jul 15. Epub 2021 Jul 15.

Institut für Pharmazeutische und Medizinische Chemie der, Westfälischen Wilhelms-Universität Münster, Corrensstraße 48, 48149, Münster, Germany.

Recent studies have shown the involvement of GluN2A subunit-containing NMDA receptors in various neurological and pathological disorders. In the X-ray crystal structure, TCN-201 (1) and analogous pyrazine derivatives 2 and 3 adopt a U-shape (hairpin) conformation within the binding site formed by the ligand binding domains of the GluN1 and GluN2A subunits. In order to mimic the resulting π/π-interactions of two aromatic rings in the binding site, a [2. Read More

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Identification of a gustatory receptor tuned to sinigrin in the cabbage butterfly Pieris rapae.

PLoS Genet 2021 Jul 15;17(7):e1009527. Epub 2021 Jul 15.

State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.

Glucosinolates are token stimuli in host selection of many crucifer specialist insects, but the underlying molecular basis for host selection in these insects remains enigmatic. Using a combination of behavioral, electrophysiological, and molecular methods, we investigate glucosinolate receptors in the cabbage butterfly Pieris rapae. Sinigrin, as a potent feeding stimulant, elicited activity in larval maxillary lateral sensilla styloconica, as well as in adult medial tarsal sensilla. Read More

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A novel class III endogenous retrovirus with a class I envelope gene in African frogs with an intact genome and developmentally regulated transcripts in Xenopus tropicalis.

Retrovirology 2021 Jul 14;18(1):20. Epub 2021 Jul 14.

Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases, Bethesda, MD, 20892, USA.

Background: Retroviruses exist as exogenous infectious agents and as endogenous retroviruses (ERVs) integrated into host chromosomes. Such endogenous retroviruses (ERVs) are grouped into three classes roughly corresponding to the seven genera of infectious retroviruses: class I (gamma-, epsilonretroviruses), class II (alpha-, beta-, delta-, lentiretroviruses) and class III (spumaretroviruses). Some ERVs have counterparts among the known infectious retroviruses, while others represent paleovirological relics of extinct or undiscovered retroviruses. Read More

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Resolving different presynaptic activity patterns within single olfactory glomeruli of Xenopus laevis larvae.

Sci Rep 2021 Jul 9;11(1):14258. Epub 2021 Jul 9.

Institute for Neurophysiology and Cellular Biophysics, University Medical Center Göttingen, 37073, Göttingen, Germany.

Olfactory sensing is generally organized into groups of similarly sensing olfactory receptor neurons converging into their corresponding glomerulus, which is thought to behave as a uniform functional unit. It is however unclear to which degree axons within a glomerulus show identical activity, how many converge into a glomerulus, and to answer these questions, how it is possible to visually separate them in live imaging. Here we investigate activity of olfactory receptor neurons and their axon terminals throughout olfactory glomeruli using electrophysiological recordings and rapid 4D calcium imaging. Read More

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Stapled, Long-Acting Xenopus GLP-1-Based Dual GLP-1/Glucagon Receptor Agonists with Potent Therapeutic Efficacy for Metabolic Disease.

Mol Pharm 2021 08 9;18(8):2906-2923. Epub 2021 Jul 9.

School of Chemistry & Materials Science, Jiangsu Normal University, Xuzhou 221116, PR China.

Novel peptidic glucagon receptor (GCGR) and glucagon-like peptide 1 receptor (GLP-1R) dual agonists are reported to have increased efficacy over GLP-1R monoagonists for the treatment of diabetes and obesity. We identified a novel GLP-1-based dual GLP-1R/GCGR agonist (xGLP/GCG-13) designed with a proper activity ratio favoring the GLP-1R versus the GCGR. However, the clinical utility of xGLP/GCG-13 is limited by its short half-life. Read More

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Identification and functional characterization of sex pheromone receptors in mirid bugs (Heteroptera: Miridae).

Insect Biochem Mol Biol 2021 09 4;136:103621. Epub 2021 Jul 4.

State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China; Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China. Electronic address:

Mirid bugs are a group of important insect pests that cause large annual losses in agricultural production. Many studies have focused on the isolation and identification of sex pheromones in mirid bugs, and the components and biological activity of the sex pheromones have also been studied as a way to control these pests. However, few studies have focused on the mechanisms of pheromone perception. Read More

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September 2021

The Wnt/PCP formin Daam1 drives cell-cell adhesion during nephron development.

Cell Rep 2021 Jul;36(1):109340

Program in Genes and Development, MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX 77030, USA; Department of Pediatrics, Pediatric Research Center, UTHealth McGovern Medical School, Houston, TX 77030, USA; Department of Genetics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA; Program in Biochemistry and Cell Biology, MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX 77030, USA. Electronic address:

E-cadherin junctions facilitate assembly and disassembly of cell contacts that drive development and homeostasis of epithelial tissues. In this study, using Xenopus embryonic kidney and Madin-Darby canine kidney (MDCK) cells, we investigate the role of the Wnt/planar cell polarity (PCP) formin Daam1 (Dishevelled-associated activator of morphogenesis 1) in regulating E-cadherin-based intercellular adhesion. Using live imaging, we show that Daam1 localizes to newly formed cell contacts in the developing nephron. Read More

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