Gap junctions and cell polarity: connexin32 and connexin43 expressed in polarized thyroid epithelial cells assemble into separate gap junctions, which are located in distinct regions of the lateral plasma membrane domain

1995 ◽  
Vol 108 (7) ◽  
pp. 2609-2617 ◽  
Author(s):  
A. Guerrier ◽  
P. Fonlupt ◽  
I. Morand ◽  
R. Rabilloud ◽  
C. Audebet ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Epithelial Cells ◽  
Gap Junctions ◽  
Cell Polarity ◽  
Laser Scanning ◽  
Thyroid Tissue ◽  
Thyroid Cell ◽  
Membrane Domain ◽  
Thyroid Cells ◽  
Connexin43 Gap Junctions

Epithelial cells of the thyroid gland present an uncommon connexin expression pattern, they coexpress connexin32 and connexin43. In the present work, we have analyzed the membrane distribution of these two connexins to determine: (i) whether they co-assemble in the same gap junctions or form separate gap junctions; and (ii) whether their location is somehow related to the thyroid cell polarity. Immunofluorescence analyses of the localization of the two connexins in thyroid tissue sections revealed that connexin32 and connexin43 are located in different regions of the plasma membrane. We further analyzed the location of each of the two connexins with regard to that of the tight junction-associated protein, ZO1. Laser scanning confocal microscope observations of connexin32 or connexin43 and ZO1 double-immunolabelled thyroid cells, gave evidence for a separate localization of gap junctions made of each of these two connexins. Connexin32 gap junctions appeared as fluorescent spots scattered over the lateral membrane domain, while connexin43 gap junctions formed a meshed network superimposable with that of tight junctions in the subapical region of the cells. Western blot analyses of the distribution of connexins in thyroid plasma membrane subfractions obtained by ultracentrifugation on a sucrose gradient led to the identification of membrane sub-populations enriched in either connexin32 gap junctions or connexin43 gap junctions. Connexin32 gap junctions and connexin43 gap junctions were found to differ in their resistance to solubilization by N-lauroylsarcosine. Increasing concentrations of this detergent from 0.12% to 0.42% caused a progressive solubilization of connexin43 while connexin32 remained membrane-bound.(ABSTRACT TRUNCATED AT 250 WORDS)

AN INVESTIGATION OF THE PATHOGENESIS OF HASHIMOTO'S DISEASE BY THYROID TISSUE CULTURE

1960 ◽  
Vol 20 (2) ◽  
pp. 83-NP ◽  
Author(s):  
W. J. IRVINE
Keyword(s):  
Tissue Culture ◽  
Alternative Hypothesis ◽  
Thyroid Tissue ◽  
Human Thyroid ◽  
Rabbit Serum ◽  
Thyroid Cell ◽  
Thyroid Extract ◽  
Thyroid Cells ◽  
Hashimoto’S Disease ◽  
Hashimoto's Disease

SUMMARY Human thyroid cells were grown in tissue culture in media containing normal human serum, Hashimoto serum, and rabbit sera containing antibodies to purified human thyroglobulin and to crude thyroid extract, respectively. The thyroid cells grew equally well in all media, with the exception of the rabbit serum containing antibodies to crude thyroid extract. Intact thyroid cells obtained from tissue culture failed to fix Hashimoto antibodies in the presence of complement, whereas the constituents of disrupted thyroid cells gave a strongly positive complement-fixation test with Hashimoto serum. It is therefore suggested that the intact thyroid cell is impermeable to complement-fixing Hashimoto antibody. The evidence afforded by the present work adds further weight to the belief that Hashimoto's disease may not be due to a simple auto-immunizing process consequent upon the interaction of thyroid antigen and the known circulating auto-antibodies. Evidence in support of an alternative hypothesis involving 'cell-bound' antibodies with disruption of the follicular basement membrane is discussed.

scholarly journals Electrostatic plasma membrane targeting contributes to Dlg function in cell polarity and tumorigenesis

Development ◽  
2021 ◽  
pp. dev.196956
Author(s):  
Juan Lu ◽  
Wei Dong ◽  
Yan Tao ◽  
Yang Hong
Keyword(s):  
Plasma Membrane ◽  
Tumor Suppressor ◽  
Epithelial Cells ◽  
Cell Polarity ◽  
Significant Role ◽  
Discs Large ◽  
Cortical Localization ◽  
Polarity Proteins ◽  
Positively Charged

Discs large (Dlg) is an essential polarity protein and a tumor suppressor originally characterized in Drosophila but is also well conserved in vertebrates. Like the majority of polarity proteins, plasma membrane (PM)/cortical localization of Dlg is required for its function in polarity and tumorigenesis, but the exact mechanisms targeting Dlg to PM remain to be fully elucidated. Here we show that, similar to the recently discovered polybasic polarity proteins such as Lgl and aPKC, Dlg also contains a positively charged polybasic domain that electrostatically binds the PM phosphoinositides PI4P and PI(4,5)P2. Electrostatic targeting by the polybasic domain contributes significantly to the PM localization of Dlg in follicular and early embryonic epithelial cells, and is crucial for Dlg to regulate both polarity and tumorigenesis. The electrostatic PM targeting of Dlg is controlled by a potential phosphorylation-dependent allosteric regulation of its polybasic domain, and is specifically enhanced by the interactions between Dlg and another basolateral polarity protein and tumor suppressor Scrib. Our studies highlight an increasingly significant role of electrostatic PM targeting of polarity proteins in regulating cell polarity.

scholarly journals Detection of SARS-COV-2 receptor ACE-2 mRNA in thyroid cells: a clue for COVID-19-related subacute thyroiditis

2020 ◽  
Author(s):  
M. Rotondi ◽  
F. Coperchini ◽  
G. Ricci ◽  
M. Denegri ◽  
L. Croce ◽  
...  
Keyword(s):  
Primary Cultures ◽  
Thyroid Tissue ◽  
Subacute Thyroiditis ◽  
Human Thyroid ◽  
Thyroid Cell ◽  
Type I ◽  
Rt Pcr ◽  
Follicular Cells ◽  
Thyroid Cells ◽  
Tissue Samples

Abstract Purpose SARS-COV-2 is a pathogenic agent belonging to the coronavirus family, responsible for the current global world pandemic. Angiotensin-converting enzyme 2 (ACE-2) is the receptor for cellular entry of SARS-CoV-2. ACE-2 is a type I transmembrane metallo-carboxypeptidase involved in the Renin-Angiotensin pathway. By analyzing two independent databases, ACE-2 was identified in several human tissues including the thyroid. Although some cases of COVID-19-related subacute thyroiditis were recently described, direct proof for the expression of the ACE-2 mRNA in thyroid cells is still lacking. Aim of the present study was to investigate by RT-PCR whether the mRNA encoding for ACE-2 is present in human thyroid cells. Methods RT-PCR was performed on in vitro ex vivo study on thyroid tissue samples (15 patients undergoing thyroidectomy for benign thyroid nodules) and primary thyroid cell cultures. Results The ACE-2 mRNA was detected in all surgical thyroid tissue samples (n = 15). Compared with two reporter genes (GAPDH: 0.052 ± 0.0026 Cycles−1; β-actin: 0.044 ± 0.0025 Cycles−1; ACE-2: 0.035 ± 0.0024 Cycles−1), the mean level of transcript expression for ACE-2 mRNA was abundant. The expression of ACE-2 mRNA in follicular cells was confirmed by analyzing primary cultures of thyroid cells, which expressed the ACE-2 mRNA at levels similar to tissues. Conclusions The results of the present study demonstrate that the mRNA encoding for the ACE-2 receptor is expressed in thyroid follicular cells, making them a potential target for SARS-COV-2 entry. Future clinical studies in patients with COVID-19 will be required for increase our understanding of the thyroid repercussions of SARS-CoV-2 infection.

scholarly journals Basolateral Localization of the Caenorhabditis elegans Epidermal Growth Factor Receptor in Epithelial Cells by the PDZ Protein LIN-10

1999 ◽  
Vol 10 (6) ◽  
pp. 2087-2100 ◽  
Author(s):  
Charles W. Whitfield ◽  
Claire Bénard ◽  
Tom Barnes ◽  
S. Hekimi ◽  
Stuart K. Kim
Keyword(s):  
Plasma Membrane ◽  
Caenorhabditis Elegans ◽  
Epithelial Cells ◽  
Egf Receptor ◽  
Basolateral Membrane ◽  
Growth Factor Receptor ◽  
Pdz Domains ◽  
Membrane Domain ◽  
Interaction Domains ◽  
New Gene

In Caenorhabditis elegans, the EGF receptor (encoded by let-23) is localized to the basolateral membrane domain of the epithelial vulval precursor cells, where it acts through a conserved Ras/MAP kinase signaling pathway to induce vulval differentiation. lin-10 acts in LET-23 receptor tyrosine kinase basolateral localization, because lin-10mutations result in mislocalization of LET-23 to the apical membrane domain and cause a signaling defective (vulvaless) phenotype. We demonstrate that the previous molecular identification oflin-10 was incorrect, and we identify a new gene corresponding to the lin-10 genetic locus.lin-10 encodes a protein with regions of similarity to mammalian X11/mint proteins, containing a phosphotyrosine-binding and two PDZ domains. A nonsense lin-10 allele that truncates both PDZ domains only partially reduces lin-10 gene activity, suggesting that these protein interaction domains are not essential for LIN-10 function in vulval induction. Immunocytochemical experiments show that LIN-10 is expressed in vulval epithelial cells and in neurons. LIN-10 is present at low levels in the cytoplasm and at the plasma membrane and at high levels at or near the Golgi. LIN-10 may function in secretion of LET-23 to the basolateral membrane domain, or it may be involved in tethering LET-23 at the basolateral plasma membrane once it is secreted.

scholarly journals The expression of the sarco/endoplasmic reticulum Ca2+-ATPases in thyroid and its down-regulation following neoplastic transformation

2003 ◽  
Vol 30 (3) ◽  
pp. 399-409 ◽  
Author(s):  
F Pacifico ◽  
L Ulianich ◽  
S De Micheli ◽  
S Treglia ◽  
A Leonardi ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Northern Blot ◽  
Blot Analysis ◽  
Thyroid Tissue ◽  
Neoplastic Transformation ◽  
Thyroid Cell ◽  
Rt Pcr ◽  
Down Regulation ◽  
Thyroid Cells ◽  
Rat Thyroid

Maintaining a high Ca(2+) concentration in the lumen of the endoplasmic reticulum (ER), by the action of sarco/endoplasmic reticulum Ca(2+)-ATPases (SERCAs), is important in many cellular processes, such as Ca(2+)-mediated cytosolic signaling in response to extracellular stimuli, cell growth and proliferation, and synthesis, processing and folding of ER-translated proteins. In the thyroid gland, SERCAs have not been studied yet, and there is little information available on general problems such as the expression of SERCAs following neoplastic transformation. In this study we investigated the expression of SERCA2b and SERCA3 in rat thyroid tIssue and, in addition, in normal and transformed rat thyroid cell lines. RT-PCR and Northern blot assays showed that SERCA2b is the SERCA form preferentially expressed in the thyroid. In rat thyroid, SERCA2b mRNA was expressed at a higher level than that of other non-muscle tIssues such as liver or spleen, but at much lower level than in brain. On the other hand, SERCA3 mRNA was not detected in thyroid by Northern blot analysis, or barely detected by RT-PCR assays. We also studied the SERCA2b expression pattern in PC Cl3 thyroid cells transformed by several oncogenes that induce different degrees of malignancy and dedifferentiation. RT-PCR and Northern blot assays showed that SERCA2b mRNA expression dramatically decreased in highly tumorigenic thyroid cells, while expression of glyceraldehyde-3-phosphate dehydrogenase mRNA, a housekeeping gene used as internal control, exhibited no variations. The dramatic down-regulation of SERCA2b expression in fully transformed thyroid cells was also evident by Western blot analysis. Also, following neoplastic transformation of thyroid cells, the enzymatic activity of SERCA2b was reduced in a measure which correlated with the mRNA and protein levels. Therefore, rat thyrocytes expressed intermediate levels of SERCAs, mostly the SERCA2b isoform. This pattern of expression was basically reproduced in fully differentiated thyroid cells in culture and was sensitive to neoplastic transformation.

Ion pumps in epithelial cells: sorting, stabilization, and polarity

1997 ◽  
Vol 272 (6) ◽  
pp. G1304-G1313 ◽  
Author(s):  
M. J. Caplan
Keyword(s):  
Plasma Membrane ◽  
Epithelial Cells ◽  
Solute Transport ◽  
Ion Pumps ◽  
Membrane Domain ◽  
Pump Function ◽  
P Type ◽  
Specific Membrane

The P-type family of ion-transporting ATPases includes all of the isoforms of Na(+)-K(+)-adenosinetriphosphatase (ATPase), the plasma membrane and organellar Ca(2+)-ATPases, gastric H(+)-K(+)-ATPase, and the recently characterized nongastric H(+)-K(+)-ATPases, among others. In epithelial cells, members of this pump family generate the cation gradients responsible for vectorial fluid and solute transport. To carry out this function, each P-type ATPase must be restricted to a specific membrane domain. Newly synthesized ion pumps must be sorted to their appropriate destinations and retained there after their delivery. Recently, progress has been made toward understanding the signals and targeting pathways that epithelial cells employ to generate anisotropic pump distributions. The mechanisms involved in generating these pump distributions may serve as well to regulate pump function.

scholarly journals Choroid plexus epithelial cells express the adhesion protein P-cadherin at cell-cell contacts and syntaxin-4 in the luminal membrane domain

2018 ◽  
Vol 314 (5) ◽  
pp. C519-C533 ◽  
Author(s):  
Inga Baasch Christensen ◽  
Esben Nees Mogensen ◽  
Helle Hasager Damkier ◽  
Jeppe Praetorius
Keyword(s):  
Plasma Membrane ◽  
Epithelial Cells ◽  
Choroid Plexus ◽  
Basolateral Membrane ◽  
Membrane Domain ◽  
Cell Contacts ◽  
Luminal Membrane ◽  
Syntaxin 4 ◽  
Choroid Plexus Epithelial ◽  
Cell Cell

The choroid plexus epithelial cells (CPECs) belong to a small group of polarized cells, where the Na+-K+-ATPase is expressed in the luminal membrane. The basic polarity of the cells is, therefore, still debated. We investigated the subcellular distribution of an array of proteins known to play fundamental roles either in establishing and maintaining basic cell polarity or in the polarized delivery and recycling of plasma membrane proteins. Immunofluorescence histochemical analysis was applied to determine the subcellular localization of apical and basolateral membrane determinants. Mass spectrometry analysis of CPECs isolated by fluorescence-activated cell sorting was applied to determine the expression of specific forms of the proteins. CPECs mainly express the cell-adhesive P-cadherin, which is localized to the lateral membranes. Proteins belonging to the Crumbs and partitioning defective (Par) protein complexes were all localized to the luminal membrane domain. Par-1 and the Scribble complex were localized to the basolateral membrane domain. Lethal(2) giant larvae homolog 2 (Lgl2) labeling was preferentially observed in the luminal membrane domain. Phosphatidylinositol 3,4,5-trisphosphate (PIP3) was immunolocalized to the basolateral membrane domain, while phosphatidylinositol 4,5-bisphosphate (PIP2) staining was most prominent in the luminal membrane domain along with the PIP3 phosphatase, Pten. The apical target-SNARE syntaxin-3 and the basolateral target-SNARE syntaxin-4 were both localized to the apical membrane domain in CPECs, which lack cellular expression of the clathrin adaptor protein AP-1B for basolateral protein recycling. In conclusion, the CPECs are conventionally polarized, but express P-cadherin at cell-cell contacts, and Lgl2 and syntaxin-4 in the luminal plasma membrane domain.

scholarly journals The sarcoplasmic–endoplasmic reticulum Ca2+ ATPase 2b regulates the Ca2+ transients elicited by P2Y2 activation in PC Cl3 thyroid cells

2006 ◽  
Vol 190 (3) ◽  
pp. 641-649 ◽  
Author(s):  
Luca Ulianich ◽  
Maria Giovanna Elia ◽  
Antonella Sonia Treglia ◽  
Antonella Muscella ◽  
Bruno Di Jeso ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Thyroid Cell ◽  
Myristate Acetate ◽  
Thyroid Cells ◽  
Pkc Inhibitor ◽  
Kinase C ◽  
Thyroid Cell Line ◽  
Rat Thyroid ◽  
Stimulation Of

In PC Cl3 cells, a continuous, fully differentiated rat thyroid cell line, P2Y2 purinoceptor activation provoked a transient increase of [Ca2+]i, followed by a decreasing sustained phase. The α and β1 protein kinase C (PKC) inhibitor Gö6976 decreased the rate of decrement to the basal [Ca2+]i level and increased the peak of Ca2+ entry of the P2Y2-provoked Ca2+transients. These effects of Gö 6976 were not caused by an increased permeability of the plasma membrane, since the Mn2+ and Ba2+ uptake were not changed by Gö 6976. Similarly, the Na+/Ca2+ exchanger was not implicated, since the rate of decrement to the basal [Ca2+]i level was equally decreased in physiological and Na+-free buffers, in the presence of Gö 6976. On the contrary, the activity of the sarcoplasmic–endoplasmic reticulum Ca2+ATPase (SERCA) 2b was profoundly affected by Gö 6976 since the drug was able to completely inhibit the stimulation of the SERCA 2b activity elicited by P2-purinergic agonists. Finally, the PKC activator phorbol myristate acetate had effects opposite to Gö 6976, in that it markedly increased the rate of decrement to the basal [Ca2+]i level after P2Y2 stimulation and also increased the activity of SERCA 2b. These results suggest that SERCA 2b plays a role in regulating the sustained phase of Ca2+ transients caused by P2Y2 stimulation.

scholarly journals Electrostatic Plasma Membrane Targeting is Essential for Dlg Function in Cell Polarity and Tumorigenesis

2020 ◽  
Author(s):  
Juan Lu ◽  
Wei Dong ◽  
Yan Tao ◽  
Yang Hong
Keyword(s):  
Plasma Membrane ◽  
Tumor Suppressor ◽  
Epithelial Cells ◽  
Cell Polarity ◽  
Primary Mechanism ◽  
Discs Large ◽  
Cortical Localization ◽  
Polarity Proteins ◽  
Positively Charged

SUMMARYDiscs large (Dlg) is an essential polarity protein and a tumor suppressor originally characterized in Drosophila but is also well conserved in vertebrates. Like the majority of polarity proteins, plasma membrane (PM)/cortical localization of Dlg is required for its function in regulating apical-basal polarity and tumorigenesis, but the exact mechanisms targeting Dlg to PM remain to be unclear. Here we show that, similar to recently discovered polybasic polarity proteins such as Lgl and aPKC, Dlg also contains a positively charged polybasic domain that electrostatically binds the PM phosphoinositides PI4P and PI(4,5)P2. Electrostatic targeting by the polybasic domain acts as the primary mechanism localizing Dlg to the PM in follicular and early embryonic epithelial cells, and is crucial for Dlg to regulate both polarity and tumorigenesis. The electrostatic PM targeting of Dlg is controlled by a potential phosphorylation-dependent allosteric regulation of its polybasic domain, and is specifically enhanced by interactions between Dlg and another basolateral polarity protein and tumor suppressor Scrib. Our studies highlight an increasingly significant role of electrostatic PM targeting of polarity proteins in regulating cell polarity.

Sign in / Sign up

Export Citation Format

Share Document