scholarly journals Immunohistochemical localization of cellCAM 105 in rat tissues: appearance in epithelia, platelets, and granulocytes.

1988 ◽  
Vol 36 (7) ◽  
pp. 729-739 ◽  
Author(s):  
P Odin ◽  
M Asplund ◽  
C Busch ◽  
B Obrink
Keyword(s):  
Cell Surface ◽  
Plasma Membranes ◽  
Surface Membrane ◽  
Cell Types ◽  
Cell Contact ◽  
Rat Tissues ◽  
Common Denominator ◽  
Surface Distribution ◽  
Organ Systems ◽  
Cell Cell

CellCAM 105 is an integral membrane glycoprotein, with apparent Mr 105,000, which has been purified from rat liver plasma membranes. It consists of two structurally similar, highly glycosylated polypeptide chains and is involved in cell-cell adhesion of adult rat hepatocytes in vitro. In this communication we report on the distribution and cell surface location of cellCAM 105 in rat tissues, obtained by using highly sensitive immunodetection systems based on complex formation between biotinylated antibodies, biotinylated peroxidase and avidin, or on antibodies coupled to alkaline phosphatase. CellCAM was found in many organs and organ systems, including liver, kidney, blood, blood vessels, glands, respiratory system, and gastrointestinal tract. It was mainly localized to epithelial structures but showed a varying cell surface distribution. In some cell types it was predominantly localized to cell-cell contact areas. In other cell types the highest concentrations were seen in brush-border areas containing densely packed microvilli. In addition to epithelial structures, cellCAM 105 was found in rat platelets, where it became strongly expressed on the cell surfaces after activation with ADP or collagen, suggesting that it might be involved in platelet adhesion and/or aggregation mechanisms. Granulocytes also contained cellCAM 105. By SDS-PAGE/immunoblotting, significant differences were found in the apparent Mr values of cellCAM 105 in different tissues. The collected data suggest that cellCAM 105 participates in several different cell surface membrane interactions, of which the common denominator might be membrane-membrane binding.

scholarly journals Amino acid transporter B0AT1 influence on ADAM17 interactions with SARS-CoV-2 receptor ACE2 putatively expressed in intestine, kidney, and cardiomyocytes

2020 ◽  
Author(s):  
Jacob T. Andring ◽  
Robert McKenna ◽  
Bruce R. Stevens
Keyword(s):  
Amino Acid ◽  
Plasma Membranes ◽  
Renin Angiotensin System ◽  
Neck Region ◽  
Cell Types ◽  
Amino Acid Transporter ◽  
Common Denominator ◽  
Organ Systems ◽  
Acid Transporter

ABSTRACTSARS-CoV-2 exhibits significant experimental and clinical gastrointestinal, renal, and cardiac muscle tropisms responsible for local tissue-specific and systemic pathophysiology capriciously occurring in about half of COVID-19 patients. The underlying COVID-19 mechanisms engaged by these extra-pulmonary organ systems are largely unknown. We approached this knowledge gap by recognizing that neutral amino acid transporter B0AT1 (alternately called NBB, B, B0 in the literature) is a common denominator expressed nearly exclusively by three particular cell types: intestinal epithelia, renal proximal tubule epithelium, and cardiomyocytes. B0AT1 provides uptake of glutamine and tryptophan. The gut is the main depot expressing over 90% of the body’s entire pool of SARS-CoV-2 receptor angiotensin converting enzyme-2 (ACE2) and B0AT1. Recent cryo-EM studies established that ACE2 forms a thermodynamically favored dimer-of-heterodimers complex with B0AT1 assembled in the form of a dimer of two ACE2:B0AT1 heterodimers anchored in plasma membranes. Prior epithelial cell studies demonstrated ACE2 chaperone trafficking of B0AT1. This contrasts with monomeric expression of ACE2 in lung pneumocytes, in which B0AT1 is undetectable. The cell types in question also express a disintegrin and metalloproteinase-17 (ADAM17) known to cleave and shed the ectodomain of monomeric ACE2 from the cell surface, thereby relinquishing protection against unchecked renin-angiotensin-system (RAS) events of COVID-19. The present study employed molecular docking modeling to examine the interplaying assemblage of ACE2, ADAM17 and B0AT1. We report that in the monomer form of ACE2, neck region residues R652-N718 provide unimpeded access to ADAM17 active site pocket, but notably R708 and S709 remained >10-15 Å distant. In contrast, interference of ADAM17 docking to ACE2 in a dimer-of-heterodimers arrangement was directly correlated with the presence of a neighboring B0AT1 subunit complexed to the partnering ACE2 subunit of the 2ACE2:2B0AT1] dimer of heterodimers, representing the expression pattern putatively exclusive to intestinal, renal and cardiomyocyte cell types. The monomer and dimer-of-heterodimers docking models were not influenced by the presence of SARS-CoV-2 receptor binding domain (RBD) complexed to ACE2. The results collectively provide the underpinnings for understanding the role of B0AT1 involvement in COVID-19 and the role of ADAM17 steering ACE2 events in intestinal and renal epithelial cells and cardiomyocytes, with implications useful for consideration in pandemic public hygiene policy and drug development.

scholarly journals Targeting of the SF/HGF receptor to the basolateral domain of polarized epithelial cells.

1994 ◽  
Vol 125 (2) ◽  
pp. 313-320 ◽  
Author(s):  
T Crepaldi ◽  
A L Pollack ◽  
M Prat ◽  
A Zborek ◽  
K Mostov ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Cell Surface ◽  
Mdck Cells ◽  
Cell Contact ◽  
Apical Surface ◽  
Surface Distribution ◽  
Polarized Epithelial Cells ◽  
Cell Cell

Scatter Factor, also known as Hepatocyte Growth Factor (SF/HGF), has pleiotropic functions including direct control of cell-cell and cell-substrate adhesion in epithelia. The subcellular localization of the SF/HGF receptor is controversial. In this work, the cell surface distribution of the SF/HGF receptor was studied in vivo in epithelial tissues and in vitro in polarized MDCK monolayers. A panel of monoclonal antibodies against the beta chain of the SF/HGF receptor stained the basolateral but not the apical surface of epithelia lining the lumen of human organs. Radiolabeled or fluorescent-tagged anti-receptor antibodies selectively bound the basolateral cell surface of MDCK cells, which form a polarized monolayer sealed by intercellular junctions, when grown on polycarbonate filters in a two-chamber culture system. The receptor was concentrated around the cell-cell contact zone, showing a distribution pattern overlapping with that of the cell adhesion molecule E-cadherin. The basolateral localization of the SF/HGF receptor was confirmed by immunoprecipitation after domain selective cell surface biotinylation. When cells were fully polarized the SF/HGF receptor became resistant to non-ionic detergents, indicating interaction with insoluble component(s). In pulse-chase labeling and surface biotinylation experiments, the newly synthesized receptor was found exclusively at the basolateral surface. We conclude that the SF/HGF receptor is selectively exposed at the basolateral plasma membrane domain of polarized epithelial cells and is targeted after synthesis to that surface by direct delivery from the trans-Golgi network.

The organization of cell surface membrane domains

1989 ◽  
Vol 47 ◽  
pp. 804-805
Author(s):  
Michael Edidin
Keyword(s):  
Cell Surface ◽  
Membrane Lipids ◽  
Surface Membrane ◽  
Lateral Diffusion ◽  
Cell Types ◽  
Membrane Domains ◽  
Membrane Biology ◽  
Morphological Polarity ◽  
Discrete Domains ◽  
Membrane Components

Cell surface membranes are based on a fluid lipid bilayer and models of the membranes' organization have emphasised the possibilities for lateral motion of membrane lipids and proteins within the bilayer. Two recent trends in cell and membrane biology make us consider ways in which membrane organization works against its inherent fluidity, localizing both lipids and proteins into discrete domains. There is evidence for such domains, even in cells without obvious morphological polarity and organization [Table 1]. Cells that are morphologically polarised, for example epithelial cells, raise the issue of membrane domains in an accute form.The technique of fluorescence photobleaching and recovery, FPR, was developed to measure lateral diffusion of membrane components. It has also proven to be a powerful tool for the analysis of constraints to lateral mobility. FPR resolves several sorts of membrane domains, all on the micrometer scale, in several different cell types.

scholarly journals Remodeling the cell surface distribution of membrane proteins during the development of epithelial cell polarity.

1992 ◽  
Vol 116 (4) ◽  
pp. 889-899 ◽  
Author(s):  
D A Wollner ◽  
K A Krzeminski ◽  
W J Nelson
Keyword(s):  
Epithelial Cell ◽  
Membrane Proteins ◽  
Cell Surface ◽  
Mdck Cells ◽  
Apical Cell ◽  
Cell Contact ◽  
Surface Polarity ◽  
Lateral Membrane ◽  
E Cadherin ◽  
Cell Cell

The development of polarized epithelial cells from unpolarized precursor cells follows induction of cell-cell contacts and requires resorting of proteins into different membrane domains. We show that in MDCK cells the distributions of two membrane proteins, Dg-1 and E-cadherin, become restricted to the basal-lateral membrane domain within 8 h of cell-cell contact. During this time, however, 60-80% of newly synthesized Dg-1 and E-cadherin is delivered directly to the forming apical membrane and then rapidly removed, while the remainder is delivered to the basal-lateral membrane and has a longer residence time. Direct delivery of greater than 95% of these proteins from the Golgi complex to the basal-lateral membrane occurs greater than 48 h later. In contrast, we show that two apical proteins are efficiently delivered and restricted to the apical cell surface within 2 h after cell-cell contact. These results provide insight into mechanisms involved in the development of epithelial cell surface polarity, and the establishment of protein sorting pathways in polarized cells.

Studies of membrane fusion. I. Paramyxovirus-induced cell fusion, a scanning electron-microscope study

1977 ◽  
Vol 28 (1) ◽  
pp. 179-188
Author(s):  
S. Knutton ◽  
D. Jackson ◽  
M. Ford
Keyword(s):  
Cell Surface ◽  
Cell Fusion ◽  
Hela Cells ◽  
Cell Swelling ◽  
Cell Contact ◽  
Cell Agglutination ◽  
Scanning Electron Microscope Study ◽  
Virus Particles ◽  
Scanning Electron ◽  
Cell Cell

Fusion of erythrocytes and HeLa cells with Sendai and Newcastle disease viruses has been studied by scanning electron microscopy. Most virus particles are spherical but vary in diameter from approximately 200 to approximately 600 nm. At 4 degrees C virus particles bind randomly to the cell surface and at high cell densities cross-linking of adjacent cells by virus particles results in cell agglutination. Cell-cell fusion takes place when the agglutinated cell suspension is warmed to 37 degrees C. Fusion is initiated at sites of cell-cell contact and is accompanied in all cases by cell swelling. In the case of suspension HeLa cells, virally mediated cell swelling involves an ‘unfolding’ of cell surface microvilli and results in the formation of smooth-surfaced single or fused cells. With erythrocytes, swelling results in haemolysis. There is a dramatic reduction in the numbers of virus particles bound to cells following fusion.

scholarly journals Kv2.1 cell surface clusters are insertion platforms for ion channel delivery to the plasma membrane

2012 ◽  
Vol 23 (15) ◽  
pp. 2917-2929 ◽  
Author(s):  
Emily Deutsch ◽  
Aubrey V. Weigel ◽  
Elizabeth J. Akin ◽  
Phil Fox ◽  
Gentry Hansen ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Cell Surface ◽  
Ion Channel ◽  
Protein Trafficking ◽  
Hippocampal Neurons ◽  
Surface Membrane ◽  
Cell Types ◽  
Homogeneous Surface ◽  
Hek Cells ◽  
Membrane Protein Trafficking

Voltage-gated K+ (Kv) channels regulate membrane potential in many cell types. Although the channel surface density and location must be well controlled, little is known about Kv channel delivery and retrieval on the cell surface. The Kv2.1 channel localizes to micron-sized clusters in neurons and transfected human embryonic kidney (HEK) cells, where it is nonconducting. Because Kv2.1 is postulated to be involved in soluble N-ethylmaleimide–sensitive factor attachment protein receptor–mediated membrane fusion, we examined the hypothesis that these surface clusters are specialized platforms involved in membrane protein trafficking. Total internal reflection–based fluorescence recovery after photobleaching studies and quantum dot imaging of single Kv2.1 channels revealed that Kv2.1-containing vesicles deliver cargo at the Kv2.1 surface clusters in both transfected HEK cells and hippocampal neurons. More than 85% of cytoplasmic and recycling Kv2.1 channels was delivered to the cell surface at the cluster perimeter in both cell types. At least 85% of recycling Kv1.4, which, unlike Kv2.1, has a homogeneous surface distribution, is also delivered here. Actin depolymerization resulted in Kv2.1 exocytosis at cluster-free surface membrane. These results indicate that one nonconducting function of Kv2.1 is to form microdomains involved in membrane protein trafficking. This study is the first to identify stable cell surface platforms involved in ion channel trafficking.

Low-affinity LFA-1/ICAM-3 interactions augment LFA-1/ICAM-1-mediated T cell adhesion and signaling by redistribution of LFA-1

2000 ◽  
Vol 113 (3) ◽  
pp. 391-400 ◽  
Author(s):  
D.A. Bleijs ◽  
M.E. Binnerts ◽  
S.J. van Vliet ◽  
C.G. Figdor ◽  
Y. van Kooyk
Keyword(s):  
T Cell ◽  
Cell Interactions ◽  
T Cell Proliferation ◽  
Cell Contact ◽  
Surface Distribution ◽  
Affinity Ligand ◽  
Large Clusters ◽  
High Affinity Ligand ◽  
Cell Cell

Although ICAM-3 is implicated in both adhesion and signal transduction events of leukocytes, its low affinity for LFA-1 compared to other ligands of LFA-1 has puzzled many investigators. Here we investigated the role of ICAM-3 in supporting LFA-1-mediated ICAM-1 binding and subsequently cell signaling. We observed that although ICAM-3 binds poorly to LFA-1 expressed on resting T cells, it specifically facilitates and increases LFA-1-mediated adhesion to the high affinity ligand of LFA-1, ICAM-1. We demonstrate that low-affinity binding of LFA-1 to ICAM-3 together with ICAM-1 alters the cell surface distribution of LFA-1 dramatically, inducing large clusters of LFA-1 that facilitate ICAM-1 binding after LFA-1 activation. We found that LFA-1-mediated ICAM-1 cell-cell interactions such as T cell proliferation greatly depend on low affinity LFA-1/ICAM-3 interactions that enhance stable LFA-1/ICAM-1 cell-cell contact. Taken together, these data demonstrate that low affinity LFA-1 binding to ICAM-3 regulates strong LFA-1/ICAM-1-mediated adhesion by driving LFA-1 into clusters to facilitate cell-cell interactions that take place in the immune system.

scholarly journals Surface membrane vesicles from mononuclear cells stimulate erythroid stem cells to proliferate in culture

Blood ◽  
1982 ◽  
Vol 60 (3) ◽  
pp. 583-594 ◽  
Author(s):  
N Dainiak ◽  
CM Cohen
Keyword(s):  
Plasma Membrane ◽  
Plasma Membranes ◽  
Mononuclear Cells ◽  
Surface Membrane ◽  
Freeze Fracture ◽  
Membrane Vesicles ◽  
Cell Types ◽  
Target Cells ◽  
Freeze Fracture Electron Microscopy

Abstract In order to examine the contribution of cell surface materials to erythroid burst-promoting activity (BPA), we separated media conditioned by a variety of human cell types into pellets and supernatants by centrifugation. When added to serum-restricted cultures of nonadherent human marrow cells, pellets contained about half of the total stimulatory activity. Freeze-fracture electron microscopy of the pellets revealed the presence of unilamellar membrane vesicles ranging from 0.10 to 0.40 microM in diameter. The amount of BPA in culture increased with added vesicle concentration in a saturable fashion. Preparation of leukocyte conditioned medium (LCM) from 125I-wheat germ agglutinin labeled cells and studies comparing the glycoprotein composition of vesicles with that of leukocyte plasma membranes suggest that LCM-derived vesicles are of plasma membrane origin. Moreover, partially purified leukocyte plasma membrane preparations also contained BPA. While disruption of vesicles by freezing/thawing and hypotonic lysis did not alter BPA, heat, trypsin, or pronase treatment removed greater than 65% of BPA, implying that vesicle surface rather than intravesicular molecules express BPA. Results of BPA assays performed in two-layer clots indicated that proximity to target cells is required for vesicle BPA expression. We conclude that membrane vesicles spontaneously shed from cell surfaces may be important regulators of erythroid burst proliferation in vitro.

scholarly journals Monocytes Upregulate Endothelial Cell Expression of Tissue Factor: A Role for Cell-Cell Contact and Cross-Talk

Blood ◽  
1997 ◽  
Vol 89 (2) ◽  
pp. 541-549 ◽  
Author(s):  
Emanuela Napoleone ◽  
Angelomaria Di Santo ◽  
Roberto Lorenzet
Keyword(s):  
Endothelial Cell ◽  
Tissue Factor ◽  
Cross Talk ◽  
Umbilical Vein ◽  
Cell Types ◽  
Cell Contact ◽  
Tnf Α ◽  
Factor Α ◽  
Cell Expression ◽  
Cell Cell

Abstract Monocytes and endothelial cells interact at sites of vascular injury during inflammatory response, thrombosis, and development of atherosclerotic lesions. Such interactions result in modulation of several biological functions of the two cell types. Because both cells, on appropriate stimulation, synthesize tissue factor (TF), we examined the effect of human umbilical vein endothelial cell (HUVEC)/monocyte coculture on the expression of TF. We found that the coincubation resulted in TF generation, which was maximal at 4 hours, increased with increasing numbers of monocytes, and required mRNA and protein synthesis. Supernatant from HUVEC/monocyte coculture induced TF activity in HUVECs, but not in monocytes, indicating that HUVEC were the cells responsible for the activity, and that soluble mediators were involved. Interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α), well-known inducers of TF in HUVECs, were found in the supernatant from the coculture, and specific antibodies directed against either cytokine inhibited TF generation. The need of IL-1β and TNF-α synthesis in order to elicit TF expression was also suggested by the delay observed in TF mRNA formation and TF activity generation when monocytes were incubated with HUVECs. IL-1β and TNF-α antigen levels in the coculture supernatant, and, consequently, HUVEC TF expression, were inhibited in the presence of anti-CD18 monoclonal antibody. These findings emphasize the role of cell-cell contact and cross-talk in the procoagulant activity, which could be responsible for the thromboembolic complications observed in those vascular disorders in which monocyte infiltration is a common feature.

scholarly journals Integrin VLA-3: ultrastructural localization at cell-cell contact sites of human cell cultures.

1989 ◽  
Vol 109 (4) ◽  
pp. 1807-1815 ◽  
Author(s):  
R Kaufmann ◽  
D Frösch ◽  
C Westphal ◽  
L Weber ◽  
C E Klein
Keyword(s):  
Human Cell ◽  
Cultured Cells ◽  
Cell Types ◽  
Cell Surface Receptor ◽  
Cell Contact ◽  
Type I ◽  
Intercellular Contact ◽  
Basal Cells ◽  
Contact Sites ◽  
Cell Cell

The integrin VLA-3 is a cell surface receptor, which binds to fibronectin, laminin, collagen type I and VI (Takada, Y., E. A. Wayner, W. G. Carter, and M. E. Hemler. 1988. J. Cell. Biochem. 37:385-393) and is highly expressed in substrate adherent cultures of almost all human cell types. The ligand specificity of VLA-3 and the inhibition of cell adhesion by anti-VLA-3 monoclonal antibodies suggest its involvement in cell-substrate interaction. In normal tissues, VLA-3 is restricted to few cell types, notably the kidney glomeruli and basal cells of the epidermis. In the epidermis, VLA-3 is generally strongly expressed on the entire plasma membrane of basal cells and is not polarized towards the basement membrane (Klein, C. E., C. Cardon-Cardo, R. Soehnchen, R. J. Cote, H. F. Oettgen, M. Eisinger, and L. J. Old. 1987. J. Invest. Dermatol. 89:500-507). Based on this finding we speculated that, in addition to a role of VLA-3 for adhesion of cells to substrate, it could also be relevant for cell-cell interaction. To investigate this, we ultrastructurally localized VLA-3 on the surface of cultured cells by immunoelectron microscopy. In accordance with our concept, we found VLA-3 strongly associated with intercellular contact sites. Interestingly, very little immunoreactivity was detected at the under-surface of cells which had been cultured for 18-32 h. This observation was unexpected but is consistent with previous findings (Kantor, R. R. S., M. J. Mattes, K. D. Lloyd, L. J. Old, and A. P. Albino. 1987. J. Biol. Chem. 262:15158-15165) which suggest that the association of VLA-3 with the basal surface of substrate adherent tumor cells is a late event occurring after days of culture under confluent conditions. However, we cannot formally rule out VLA-3 expression at the undersurface of cells under our experimental conditions, since VLA-3 molecules at this location could be inaccessible for in situ labeling of unfixed cells because of spatial interferences. In conclusion, our results demonstrate the expression of VLA-3 at intercellular contact sites of cultured cells supporting the concept that it may be relevant for intercellular interactions also.

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