Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

In Situ Structure of Intestinal Apical Surface Reveals Nanovilli on Microvilli

ABSTRACT: Microvilli are actin bundle-supported membrane protrusions essential for absorption, secretion, and sensation. Microvilli defects cause human diseases, including gastrointestinal disorders and inherited deafness; however, mechanisms controlling microvilli formation and organization remain unclear. Here, we study microvilli by vitrifying the C. elegans larvae and mouse intestinal tissues with high-pressure freezing, thinning them by cryo-focused ion beam milling, cryo-electron tomography, and sub-tomogram averaging. We show that hundreds of previously unrecognized stick-like structures, which we refer to as nanovilli, decorate the lateral surface of C. elegans and mouse microvilli. The C. elegans 37.5-nm long and 4.5-nm wide nanovilli are composed of the protocadherin family protein CDH-8. Loss of nanovilli slows down animal growth and increases the number of Y-shaped microvilli, intermediate structures when a microvillus splits from its tip and separates into two. Our results indicate that nanovilli space microvilli and suggest a microvilli division model through which microvilli assemble with striking uniformity.

ORGANISM(S): Caenorhabditis elegans

PROVIDER: GSE167859 | GEO | 2021/04/30

REPOSITORIES: GEO

ACCESS DATA

Json Xml

Dataset's files

Source:

			Action	DRS
		Other

Items per page:

1 - 1 of 1

Similar Datasets

CDK1-formin signal confers microvillar effacement by an attaching and effacing (A/E) pathogen

Project description:Enterohemorrhagic Escherichia coli (EHEC) induces the attachment and effacement of intestinal microvilli. While the molecular mechanisms contributed to the attachment of EHEC have been thoroughly studied, the underlying mechanisms for the effacement of intestinal microvilli induced by EHEC remained elusive. By focus RNAi screening and genetic analysis in C. elegans and further reconfirmed in human Caco-2 intestinal epithelial cells, we demonstrate that the CDK1-formin signal axis is required for this EHEC-induced microvillar effacement in vitro and in vivo.

2020-11-11 | GSE142507 | GEO

Phosphoproteome of SARS-CoV-2 infected Human Nasal Epithelium

Project description:The nasal epithelium is the primary initial site of SARS-CoV-2 entry in the human body. Since much of the molecular detail defining coronavirus entry and replication was derived from non-nasal cell lines, it remains unclear how SARS-CoV-2 overcomes the physical nasal mucus and periciliary mucin layers to infect and spread through the nasal epithelium. Using air-liquid interface cultured primary nasal epithelial cells, we observed that SARS-CoV-2 attaches to motile cilia during the initial stage of infection. Depletion of cilia inhibited SARS-CoV-2, as well as respiratory syncytial virus and parainfluenza virus infection, suggesting a widely-used ciliary mechanism for respiratory viral entry. Using electron and immunofluorescence microscopy, we further observed that SARS-CoV-2 progeny virions attached to airway microvilli 24 hours post infection and triggered the formation of apically extended and highly branched microvilli that organize viral egress from the microvillar base back into the mucus layer, supporting a model of virus dispersion throughout airway tissue via mucociliary transport. Chemical perturbation of microvillus formation severely impaired viral egress and subsequent spread. Phosphoproteomic analyses indicate that virally-triggered microvillar branching is linked to the p21-activated kinase 1 and 4 (PAK1/4) signaling pathway and viral infection is impaired by PAK1/4 kinase inhibitors. Our work provides insight into the mechanisms by which SARS-CoV-2 and potentially many respiratory viruses penetrate the physical nasal epithelium barrier, a first line of defense against pathogens, thus revealing a new view of the motile cilia and microvilli as critical host factors required for viral entry and egress.

2023-03-10 | PXD028123 | Pride

Loss-of-function of MYO5B induces epithelial cell scattering in enterocytes

Project description:A non-functional myosin Vb motor in duodenal enterocytes results in disruption of epithelial cell polarity characterized by complete loss of microvilli and mislocalization of apical brush border proteins in the cytoplasm which finally cause a devastating disease in neonates with severe malabsorption defects accompanied by protracted diarrhea during infancy, classified as microvillus inclusion disease (MVID). The exact mechanisms how loss-of-function of MYO5B induces polarity loss are not completely understood in MVID pathogenesis. Obtaining better insights in cell polarity defects caused by loss of MYO5B, we performed microarray- in combination with protein expression-analysis in an inducible CaCo2 MYO5B RNAi cell system. Surprisingly, in MYO5B-depleted CaCo2 cells, CDH1 coding for the cell adhesion protein E-Cadherin and important for cell adhesion and therefore maintenance of cell polarity, was significantly downregulated. Interestingly, mesenchymal cell markers, specifically Vimentin and N-Cadherin, physiologically not expressed in differentiated epithelium, were upregulated and accompanied by increased phospho-c-jun levels in the nucleus. Importantly phospho-c-jun was also found in nuclei of duodenal enterocytes in MVID patients, indicating loss of MYO5B induces epithelial cell scattering in enterocytes. 3 Myosin 5B KD versus 3 control samples

2013-03-14 | E-GEOD-45134 | biostudies-arrayexpress

Structural basis of nucleosomal H4K20 recognition and methylation by SUV420H1 methyltransferase

Project description:Here we report the cryo-electron microscopy (cryo-EM) structures of SUV420H1 associated with canonical nucleosome core particles (NCPs) or H2AZ containing NCPs. We find that SUV420H1 shows conformational change after bound to a nucleosome and make extensive site-specific contacts with histone and DNA regions, thus enabling H4K20 insertion for catalysis specifically. Through in vivo functional analysis, we validated special residues of SUV420H1 that are critical for its catalytic activity and function in chromatin state regulation.Thus, our study provides molecular insights into the nucleosome-based recognition and histone- methylation mechanisms of SUV420H1.

2023-12-04 | GSE236249 | GEO

Analysis of active and inactive X chromosome architecture reveals the independent organization of 30-nm and large scale chromatin structures

Project description:Using a genetic model, we present a high resolution chromatin fibre analysis of transcriptionally active (Xa) and inactive (Xi) X chromosomes packaged into euchromatin and facultative heterochromatin. Our results show that gene promoters have an open chromatin structure that is enhanced upon transcriptional activation but the Xa and the Xi have similar overall 30-nm chromatin fibre structures. Therefore, the formation of facultative heterochromatin is dependent on factors that act at a level above the 30-nm fibre and transcription does not alter bulk chromatin fibre structures. However, large scale chromatin structures on Xa are decondensed compared to the Xi and transcription inhibition is sufficient to promote large scale chromatin compaction. We show a link between transcription and large scale chromatin packaging independent of the bulk 30-nm chromatin fibre and propose that transcription, not the global compaction of 30-nm chromatin fibres, determines the cytological appearance of large scale chromatin structures. This SuperSeries is composed of the SubSeries listed below.

2010-08-27 | GSE23818 | GEO

Loss-of-function of MYO5B induces epithelial cell scattering in enterocytes

2013-03-14 | GSE45134 | GEO

Gene-Edited Human Kidney Organoids Reveal Mechanisms of Disease in Podocyte Development

Project description:A critical event during kidney organogenesis is the differentiation of podocytes, specialized epithelial cells that filter blood plasma to form urine. Podocytes derived from human pluripotent stem cells (hPSC-podocytes) have recently been generated in nephron-like kidney organoids, but the developmental stage of these cells and their capacity to reveal disease mechanisms remains unclear. Here, we show that hPSC-podocytes phenocopy mammalian podocytes at the capillary loop stage (CLS), recapitulating key features of ultrastructure, gene expression, and mutant phenotype. hPSC-podocytes in vitro progressively establish junction-rich basal membranes (nephrin+ podocin+ ZO-1+) and microvillus-rich apical membranes (podocalyxin+), similar to CLS podocytes in vivo. Ultrastructural, biophysical, and transcriptomic analysis of podocalyxin-knockout hPSCs and derived podocytes, generated using CRISPR/Cas9, reveals defects in the assembly of microvilli and lateral spaces between developing podocytes, resulting in failed junctional migration. These defects are phenocopied in CLS glomeruli of podocalyxin-deficient mice, which cannot produce urine, thereby demonstrating that podocalyxin has a conserved and essential role in mammalian podocyte maturation. Defining the maturity of hPSC-podocytes and their capacity to reveal and recapitulate pathophysiological mechanisms establishes a powerful framework for studying human kidney disease and regeneration.

2017-09-20 | GSE103547 | GEO

Proteomics analysis between T cell lysate and T cell microvilli-derived particles

Project description:Although T cell activation is closely linked to internalization of the T cell antigen receptor (TCR), relatively few studies have examined the release of TCRs via shedding of T cell microvilli following physical interaction with cognate antigen-presenting cells. In this study, we investigated the physiological implications of the release of TCRs and other external membrane components. We term this event “trogocytic molting”, as it occurs through a combined process of trogocytosis and enzymatic vesiculation of microvillar membrane structures. Surprisingly, in contrast to TCR internalization, this event leads to rapid upregulation of surface TCRs and remarkable metabolic reprogramming of cholesterol and fatty acids synthesis to meet the demands of clonal expansion, which drives multiple rounds of division and cell survival. To elucidate a potential mechanism for how trogocytic molting of microvilli enhances T-cell proliferation, purified TISs obtained from activated naive CD3+ T cells were subjected to LC-MS/MS analysis to identify TISs-enriched functional proteins.

2023-05-09 | PXD041442 | Pride

Ribosome collisions trigger subunit splitting in E. coli

Project description:Although many clinically important antibiotics inhibit bacterial ribosomes, the mechanisms by which bacterial cells rescue ribosomes stalled by antibiotics remain poorly understood. Ribosome stalling leads to collisions that recruit ribosome quality control (RQC) factors that recycle the ribosome subunits and target nascent proteins for degradation. Surprisingly, loss of known RQC factors in E. coli does not lead to significant antibiotic sensitivity, even though antibiotics stall ribosomes and induce collisions, suggesting the existence of additional, uncharacterized RQC mechanisms. Here we report a novel mechanism for ribosome quality control (RQC) in bacteria in which the DExH-box ATPase HrpA splits stalled ribosomes into subunits. HrpA selectively acts on collided ribosomes and its activity is dependent on ATP hydrolysis. The cryo-EM structure of HrpA bound to collided ribosomes reveals insight into its selectivity and mechanism: the C-terminal domain of HrpA senses the collision and its helicase domain bind mRNA downstream of the ribosomes, where it likely exerts a pulling force that destabilizes the stalled ribosome. These studies highlight the importance of ribosome splitting as a highly conserved RQC mechanism across all three domains of life and identify an important pathway in proteobacteria that allows proteobacteria to tolerate ribosome-targeting antibiotics.

2024-10-10 | GSE270401 | GEO

Intestinal epithelial microvilli are abnormal in Crohn's disease

Project description:Intestinal epithelial microvilli are abnormal in Crohn's disease

| PRJNA445829 | ENA