scholarly journals Possible Involvement of Tight Junctions, Extracellular Matrix and Nuclear Receptors in Epithelial Differentiation

2011 ◽  
Vol 2011 ◽  
pp. 1-10 ◽  
Author(s):  
Naoki Ichikawa-Tomikawa ◽  
Kotaro Sugimoto ◽  
Seiro Satohisa ◽  
Keisuke Nishiura ◽  
Hideki Chiba
Keyword(s):  
Extracellular Matrix ◽  
Plasma Membrane ◽  
Tight Junctions ◽  
Nuclear Receptors ◽  
Functional Significance ◽  
Transmembrane Proteins ◽  
Intercellular Junctions ◽  
Epithelial Differentiation ◽  
Scaffolding Proteins ◽  
Fence Function

Tight junctions are intercellular junctions localized at the most apical end of the lateral plasma membrane. They consist of four kinds of transmembrane proteins (occludin, claudins, junctional adhesion molecules, and tricellulin) and huge numbers of scaffolding proteins and contribute to the paracellular barrier and fence function. The mutation and deletion of these proteins impair the functions of tight junctions and cause various human diseases. In this paper, we provide an overview of recent studies on transmembrane proteins of tight junctions and highlight the functional significance of tight junctions, extracellular matrix, and nuclear receptors in epithelial differentiation.

scholarly journals Claudin-4 Reconstituted in Unilamellar Vesicles is Sufficient to Form Tight Interfaces that Partition Membrane Proteins

2018 ◽  
Author(s):  
Brian Belardi ◽  
Sungmin Son ◽  
Michael D. Vahey ◽  
Jinzhi Wang ◽  
Jianghui Hou ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Membrane Proteins ◽  
Epithelial Cells ◽  
Tight Junctions ◽  
Direct Evidence ◽  
Accessory Proteins ◽  
Unilamellar Vesicles ◽  
Outer Leaflet ◽  
Fence Function

AbstractTight junctions have been hypothesized to act as molecular fences in the plasma membrane of epithelial cells, helping to form differentiated apical and basolateral domains. While this fence function is believed to arise from the interaction of four-pass transmembrane claudins, the complexity of tight junctions has made direct evidence of their role as a putative diffusion barrier difficult to obtain. Here we address this challenge by reconstituting claudin-4 into giant unilamellar vesicles using microfluidic jetting. We find that reconstituted claudin-4 is sufficient to form adhesive interfaces between unilamellar vesicles without accessory proteins present in vivo. By controlling the molecular composition of the inner and outer leaflets of jetted membranes, we show that claudin-4-mediated interfaces can drive partitioning of extracellular membrane proteins but not of inner or outer leaflet lipids. Our findings indicate that homotypic interactions of claudins and their small size can contribute to the polarization of epithelial cells.

The extracellular matrix of echinoderm and amphibian eggs: Visualization in quick-frozen, deep-etched, and rotary-shadowed specimens

1990 ◽  
Vol 48 (3) ◽  
pp. 60-61
Author(s):  
Barry Bonnell ◽  
Carolyn Larabell ◽  
Douglas Chandler
Keyword(s):  
Extracellular Matrix ◽  
Plasma Membrane ◽  
Sea Urchin ◽  
Crystalline Structure ◽  
Cortical Granule ◽  
Two Dimensional ◽  
Small Peptides ◽  
Deep Etching ◽  
Quick Freezing ◽  
Acrosomal Reaction

Eggs of many species including those of echinoderms, amphibians and mammals exhibit an extensive extracellular matrix (ECM) that is important both in the reception of sperm and in providing a block to polyspermy after fertilization.In sea urchin eggs there are two distinctive coats, the vitelline layer which contains glycoprotein sperm receptors and the jelly layer that contains fucose sulfate glycoconjugates which trigger the acrosomal reaction and small peptides which act as chemoattractants for sperm. The vitelline layer (VL), as visualized by quick-freezing, deep-etching, and rotary-shadowing (QFDE-RS), is a fishnet-like structure, anchored to the plasma membrane by short posts. Orbiting above the VL are horizontal filaments which are thought to anchor the thicker jelly layer to the egg. Upon fertilization, the VL elevates and is transformed by cortical granule secretions into the fertilization envelope (FE). The rounded casts of microvilli in the VL are transformed into angular peaks and the envelope becomes coated inside and out with sheets of paracrystalline protein having a quasi-two dimensional crystalline structure.

scholarly journals A family of pathogen-induced cysteine-rich transmembrane proteins is involved in plant disease resistance

Planta ◽  
2021 ◽  
Vol 253 (5) ◽  
Author(s):  
Marciel Pereira Mendes ◽  
Richard Hickman ◽  
Marcel C. Van Verk ◽  
Nicole M. Nieuwendijk ◽  
Anja Reinstädler ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Plasma Membrane ◽  
Disease Resistance ◽  
Plant Disease Resistance ◽  
Transmembrane Proteins ◽  
Series Data ◽  
Immune Gene ◽  
Biological Processes ◽  
Hypocotyl Growth ◽  
Enhanced Resistance

Abstract Main conclusion Overexpression of pathogen-induced cysteine-rich transmembrane proteins (PCMs) in Arabidopsis thaliana enhances resistance against biotrophic pathogens and stimulates hypocotyl growth, suggesting a potential role for PCMs in connecting both biological processes. Abstract Plants possess a sophisticated immune system to protect themselves against pathogen attack. The defense hormone salicylic acid (SA) is an important player in the plant immune gene regulatory network. Using RNA-seq time series data of Arabidopsis thaliana leaves treated with SA, we identified a largely uncharacterized SA-responsive gene family of eight members that are all activated in response to various pathogens or their immune elicitors and encode small proteins with cysteine-rich transmembrane domains. Based on their nucleotide similarity and chromosomal position, the designated Pathogen-induced Cysteine-rich transMembrane protein (PCM) genes were subdivided into three subgroups consisting of PCM1-3 (subgroup I), PCM4-6 (subgroup II), and PCM7-8 (subgroup III). Of the PCM genes, only PCM4 (also known as PCC1) has previously been implicated in plant immunity. Transient expression assays in Nicotiana benthamiana indicated that most PCM proteins localize to the plasma membrane. Ectopic overexpression of the PCMs in Arabidopsis thaliana resulted in all eight cases in enhanced resistance against the biotrophic oomycete pathogen Hyaloperonospora arabidopsidis Noco2. Additionally, overexpression of PCM subgroup I genes conferred enhanced resistance to the hemi-biotrophic bacterial pathogen Pseudomonas syringae pv. tomato DC3000. The PCM-overexpression lines were found to be also affected in the expression of genes related to light signaling and development, and accordingly, PCM-overexpressing seedlings displayed elongated hypocotyl growth. These results point to a function of PCMs in both disease resistance and photomorphogenesis, connecting both biological processes, possibly via effects on membrane structure or activity of interacting proteins at the plasma membrane.

scholarly journals Caveolins, a Family of Scaffolding Proteins for Organizing “Preassembled Signaling Complexes” at the Plasma Membrane

1998 ◽  
Vol 273 (10) ◽  
pp. 5419-5422 ◽  
Author(s):  
Takashi Okamoto ◽  
Amnon Schlegel ◽  
Philipp E. Scherer ◽  
Michael P. Lisanti
Keyword(s):  
Plasma Membrane ◽  
Scaffolding Proteins

scholarly journals Structural and Functional Regulation of Tight Junctions by RhoA and Rac1 Small GTPases

1998 ◽  
Vol 142 (1) ◽  
pp. 101-115 ◽  
Author(s):  
Tzuu-Shuh Jou ◽  
Eveline E. Schneeberger ◽  
W. James Nelson
Keyword(s):  
Tight Junctions ◽  
Spatial Organization ◽  
Mdck Cells ◽  
Protein Localization ◽  
Freeze Fracture ◽  
Tracer Diffusion ◽  
Small Gtpases ◽  
Dominant Negative ◽  
Solute Diffusion ◽  
Fence Function

Tight junctions (TJ) govern ion and solute diffusion through the paracellular space (gate function), and restrict mixing of membrane proteins and lipids between membrane domains (fence function) of polarized epithelial cells. We examined roles of the RhoA and Rac1 GTPases in regulating TJ structure and function in MDCK cells using the tetracycline repressible transactivator to regulate RhoAV14, RhoAN19, Rac1V12, and Rac1N17 expression. Both constitutively active and dominant negative RhoA or Rac1 perturbed TJ gate function (transepithelial electrical resistance, tracer diffusion) in a dose-dependent and reversible manner. Freeze-fracture EM and immunofluoresence microscopy revealed abnormal TJ strand morphology and protein (occludin, ZO-1) localization in RhoAV14 and Rac1V12 cells. However, TJ strand morphology and protein localization appeared normal in RhoAN19 and Rac1N17 cells. All mutant GTPases disrupted the fence function of the TJ (interdomain diffusion of a fluorescent lipid), but targeting and organization of a membrane protein in the apical membrane were unaffected. Expression levels and protein complexes of occludin and ZO-1 appeared normal in all mutant cells, although ZO-1 was more readily solubilized from RhoAV14-expressing cells with Triton X-100. These results show that RhoA and Rac1 regulate gate and fence functions of the TJ, and play a role in the spatial organization of TJ proteins at the apex of the lateral membrane.

scholarly journals Lateral diffusion of wild-type and mutant Ld antigens in L cells.

1984 ◽  
Vol 99 (6) ◽  
pp. 2333-2335 ◽  
Author(s):  
M Edidin ◽  
M Zuniga
Keyword(s):  
Plasma Membrane ◽  
Diffusion Coefficients ◽  
Transmembrane Protein ◽  
Transmembrane Proteins ◽  
Lateral Diffusion ◽  
Cytoplasmic Domain ◽  
Histocompatibility Antigen ◽  
Wild Type ◽  
Major Histocompatibility Antigen ◽  
Cytoplasmic Side

We have compared the lateral diffusion of intact transmembrane proteins, wild-type H-2Ld antigens, with that of mutants truncated in the cytoplasmic domain. Diffusion coefficients and mobile fractions were similar for all molecules examined, from wild-type Ld antigens with 31 residues on the cytoplasmic side of the plasma membrane to mutants with only four residues in the cytoplasmic domain. This result limits ways in which the lateral diffusion of a major histocompatibility antigen, a transmembrane protein, can be constrained by interactions with other molecules.

Tight junctions

1998 ◽  
Vol 111 (5) ◽  
pp. 541-547 ◽  
Author(s):  
M.S. Balda ◽  
K. Matter
Keyword(s):  
Endothelial Cells ◽  
Cell Growth ◽  
Tight Junctions ◽  
Diffusion Barrier ◽  
Basolateral Membrane ◽  
Intercellular Junctions ◽  
Cellular Level ◽  
Cellular Processes ◽  
Cell Growth And Differentiation ◽  
Membrane Components

Tight junctions are the most apical intercellular junctions of epithelial and endothelial cells and create a regulatable semipermeable diffusion barrier between individual cells. On a cellular level, they form an intramembrane diffusion fence that restricts the intermixing of apical and basolateral membrane components. In addition to these well defined functions, more recent evidence suggests that tight junctions are also involved in basic cellular processes like the regulation of cell growth and differentiation.

scholarly journals Neuronal receptors display cytoskeleton-independent directed motion on the plasma membrane

2018 ◽  
Author(s):  
R. D. Taylor ◽  
M. Heine ◽  
N. J. Emptage ◽  
L. C. Andreae
Keyword(s):  
Plasma Membrane ◽  
Neuronal Activity ◽  
Particle Tracking ◽  
Hippocampal Neurons ◽  
Intracellular Transport ◽  
Transmembrane Proteins ◽  
Single Particle Tracking ◽  
Directed Motion ◽  
Surface Movement ◽  
Transport Vesicles

AbstractDirected transport of transmembrane proteins is generally believed to occur via intracellular transport vesicles. However, using single particle tracking in rat hippocampal neurons with a pH-sensitive quantum dot probe which specifically reports surface movement of receptors, we have identified a subpopulation of neuronal EphB2 receptors that exhibit directed motion between synapses within the plasma membrane itself. This receptor movement occurs independently of the cytoskeleton but is dependent on cholesterol and is regulated by neuronal activity.

scholarly journals STIM1- and Orai1-mediated Ca2+ oscillation orchestrates invadopodium formation and melanoma invasion

2014 ◽  
Vol 207 (4) ◽  
pp. 535-548 ◽  
Author(s):  
Jianwei Sun ◽  
Fujian Lu ◽  
Huifang He ◽  
Junling Shen ◽  
Jane Messina ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Plasma Membrane ◽  
Mouse Model ◽  
Matrix Metalloproteinase ◽  
Cell Invasion ◽  
Cancer Cell Invasion ◽  
Invasion And Metastasis ◽  
Melanoma Invasion ◽  
Ecm Degradation ◽  
Underlying Mechanisms

Ca2+ signaling has been increasingly implicated in cancer invasion and metastasis, and yet, the underlying mechanisms remained largely unknown. In this paper, we report that STIM1- and Orai1-mediated Ca2+ oscillations promote melanoma invasion by orchestrating invadopodium assembly and extracellular matrix (ECM) degradation. Ca2+ oscillation signals facilitate invadopodial precursor assembly by activating Src. Disruption of Ca2+ oscillations inhibited invadopodium assembly. Furthermore, STIM1 and Orai1 regulate the proteolysis activity of individual invadopodia. Mechanistically, Orai1 blockade inhibited the recycling of MT1–matrix metalloproteinase (MMP) to the plasma membrane and entrapped MT1-MMP in the endocytic compartment to inhibit ECM degradation. STIM1 knockdown significantly inhibited melanoma lung metastasis in a xenograft mouse model, implicating the importance of this pathway in metastatic dissemination. Our findings provide a novel mechanism for Ca2+-mediated cancer cell invasion and shed new light on the spatiotemporal organization of store-operated Ca2+ signals during melanoma invasion and metastasis.

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