Changes in cell surface expression of fibronectin and fibronectin receptor during liver regeneration

1992 ◽  
Vol 102 (4) ◽  
pp. 815-820
Author(s):  
C. Pujades ◽  
E. Forsberg ◽  
C. Enrich ◽  
S. Johansson
Keyword(s):  
Extracellular Matrix ◽  
Liver Regeneration ◽  
Immunohistochemical Staining ◽  
Plasma Membranes ◽  
Surface Expression ◽  
Cell Surface Expression ◽  
Pericellular Matrix ◽  
Plasma Fibronectin ◽  
Integrin Receptor ◽  
Fibronectin Receptor

The surface expression of fibronectin and its major integrin receptor in liver, integrin alpha 5 beta 1, was studied during liver regeneration after partial hepatectomy. Using immunoblotting, plasma membranes isolated from livers at different regeneration stages were found to contain 6- to 8-fold elevated levels of fibronectin, alpha 5 and beta 1 at 12–24 h after the operation. Normal levels were gradually restored during the following 8–9 days. The membrane-associated fibronectin lacked the ED-A domain, suggesting that it consisted of plasma fibronectin. A prominent fibronectin fragment (180 kDa) was present at 12–24 h after surgery, possibly reflecting turnover of the pericellular matrix during cell division. Indirect immunohistochemical staining of liver sections revealed beta 1 and fibronectin mainly in the sinusoidal region of the hepatocyte plasma membrane. The distribution was not markedly altered during liver regeneration. The results suggest that the fibronectin-mediated contacts between the cells and the extracellular matrix increase during the pre-replicative and proliferative phases of liver regeneration. The significance of these results for the growth and for the structure of the liver during regeneration and development is discussed.

HEMCAM/CD146 downregulates cell surface expression of (β)1 integrins

2001 ◽  
Vol 114 (10) ◽  
pp. 1847-1859 ◽  
Author(s):  
S. Alais ◽  
N. Allioli ◽  
C. Pujades ◽  
J.L. Duband ◽  
O. Vainio ◽  
...  
Keyword(s):  
Cell Surface ◽  
Surface Expression ◽  
Matrix Proteins ◽  
Cell Surface Expression ◽  
Immunoglobulin Superfamily ◽  
Fibronectin Receptor ◽  
Adhesion Properties ◽  
Murine Fibroblasts ◽  
Laminin 1 ◽  
Immunoglobulin Superfamily Protein

HEMCAM/gicerin, an immunoglobulin superfamily protein, is involved in homophilic and heterophilic adhesion. It interacts with NOF (neurite outgrowth factor), a molecule of the laminin family. Alternative splicing leads to mRNAs coding for HEMCAM with a short (HEMCAM-s) or a long cytoplasmic tail (HEMCAM-l). To investigate the cellular function of these two variants, we stably transfected murine fibroblasts with either form of HEMCAM. Expression of each isoform of this protein in L cells delayed proliferation and modified their adhesion properties to purified extracellular matrix proteins. Expression of either HEMCAM-s or HEMCAM-l inhibited integrin-dependent adhesion and spreading of fibroblasts to laminin 1, showing that this phenomenon did not depend on the cytoplasmic region. By contrast, L-cell adhesion and spreading to fibronectin depended on the HEMCAM isoform expressed. Flow cytometry and immunoprecipitation studies revealed that the expression of HEMCAM downregulated expression of the laminin-binding integrins (α)3 (β)1, (α)6 (β)1 and (α)7 (β)1, and fibronectin receptor (α)5 (β)1 from the cell surface. Semi-quantitative PCR and northern blot experiments showed that the expression of (α)6 (β)1 integrin modified by HEMCAM occurred at a translation or maturation level. Thus, our data demonstrate that HEMCAM regulates fibroblast adhesion by controlling (β)1 integrin expression. http://www.biologists.com/JCS/movies/jcs1886.html

scholarly journals Binding of fibronectin to alpha-granule-deficient platelets.

1983 ◽  
Vol 97 (2) ◽  
pp. 571-573 ◽  
Author(s):  
M H Ginsberg ◽  
J D Wencel ◽  
J G White ◽  
E F Plow
Keyword(s):  
Surface Expression ◽  
Plasma Fibronectin ◽  
Platelet Factor ◽  
Fibronectin Receptor ◽  
Platelet Binding ◽  
Protein Functions ◽  
Fibronectin Binding ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Molecular Nature

Most of the proposed functions for fibronectin involve its interaction with cells, yet the molecular nature of cellular fibronectin binding site(s) has remained obscure. Thrombin induces saturable platelet binding sites for plasma fibronectin and concurrently stimulates surface expression of a number of platelet alpha-granule constituents including thrombospondin and fibrin which are known to interact with fibronectin. To test the hypothesis that these (or other alpha-granule proteins) mediate plasma fibronectin binding, we used platelets of patients with the Gray Platelet Syndrome. These cells were deficient in thrombospondin, beta-thromboglobulin, platelet factor 4, fibronectin, and fibrinogen as measured in radioimmunoassay. They also had reduced von Willebrand factor content as judged by immunofluorescence. At plasma fibronectin inputs from 0.03 to 3 times the apparent kilodalton, these Gray platelets bound virtually identical quantities of fibronectin as normal cells. Thus, platelets containing 1,500 molecules of thrombospondin per platelet could bind more than 100,000 molecules of plasma fibronectin per cell following thrombin stimulation. These data preclude any simple model in which newly surface expressed thrombospondin (or other alpha-granule protein) functions as the major thrombin-stimulated plasma fibronectin receptor in this cell type.

scholarly journals HIV-1 infection of human T lymphocytes results in enhanced alpha 5 beta 1 integrin expression.

1991 ◽  
Vol 114 (4) ◽  
pp. 847-853 ◽  
Author(s):  
B S Weeks ◽  
M E Klotman ◽  
S Dhawan ◽  
M Kibbey ◽  
J Rappaport ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Monoclonal Antibodies ◽  
T Cell ◽  
Cell Surface Expression ◽  
Viral Gene ◽  
Type I ◽  
Cell Adherence ◽  
Fibronectin Receptor ◽  
Beta 1 Integrin ◽  
Hiv 1

Altered T cell adherence after human immunodeficiency virus 1 (HIV-1) infection may contribute to viral pathogenesis in the acquired immune deficiency syndrome. To address this hypothesis, we assessed mechanisms of T cell adherence to extracellular matrix proteins in vitro. We found that after HIV-1 infection, both chronically infected H9 CD4+ T cells and acutely infected primary peripheral blood lymphocytes acquired the ability to adhere to the extracellular matrix glycoprotein fibronectin, to a lesser extent to type IV collagen and laminin, but not to type I collagen. H9 cells chronically infected with two of the three HIV-1 strains studied showed approximately a sevenfold increase in attachment to fibronectin, while the same cells infected with the human retrovirus HIV-2 did not. Adhesion was accompanied by changes in morphology, including marked spreading and increased filopodia. These alterations were not blocked by the protein kinase C inhibitor H-7, which did inhibit TPA-induced T cell attachment to fibronectin. Monoclonal antibodies against both the alpha 5 and the beta 1 subunits of the classical fibronectin receptor as well as an Arg-Gly-Asp (RGD) peptide inhibited attachment, whereas anti-alpha 4 monoclonal antibodies and the CS1 peptide did not. Binding to collagen IV was also inhibited by the anti-beta 1 monoclonal antibody, but not the other antibodies. Cells metabolically labeled with [35S]methionine and analyzed by immunoprecipitation with polyclonal anti-beta 1 integrin antibody showed a 2.5-fold increase in integrin synthesis in infected cells compared to uninfected controls. This increase in synthesis was associated with an increase in cell surface expression of both alpha 5 and beta 1 integrins by FACS (registered trademark of Becton Dickinson for a fluorescence-activated cell sorter) analysis. Enhanced expression of integrins such as alpha 5 beta 1 may cause T cell adherence to a variety of tissues, where released viral gene products may induce some of the tissue-specific manifestations of HIV-1 infection.

scholarly journals Role of Pgrmc1 in estrogen maintenance of meiotic arrest in zebrafish oocytes through Gper/Egfr

2015 ◽  
Vol 225 (1) ◽  
pp. 59-68 ◽  
Author(s):  
Joseph Aizen ◽  
Peter Thomas
Keyword(s):  
Cell Surface ◽  
Cell Membranes ◽  
Plasma Membranes ◽  
Growth Factor Receptor ◽  
Surface Expression ◽  
Cell Surface Expression ◽  
Target Cells ◽  
Meiotic Arrest ◽  
Egfr Expression

The regulation of receptor trafficking to the cell surface and its effect on responses of target cells to growth factors and hormones remain poorly understood. Initial evidence has been recently obtained using cancer cells that surface expression of the epidermal growth factor receptor (EGFR) is dependent on its association with progesterone receptor membrane component 1 (PGRMC1). Estrogen inhibition of oocyte maturation (OM) in zebrafish is mediated through G-protein-coupled estrogen membrane receptor 1 (Gper1) and involves activation of Egfr. Therefore, in this study, the potential roles of Pgrmc1 in the cell surface expression and functions of Egfr in normal cells were investigated in this in vitro OM model of Egfr action using an inhibitor of PGMRC1 signaling, AG205. A single ∼60 kDa protein band, which corresponds to the size of the Pgrmc1 dimer, was detected on plasma membranes of fully grown oocytes by western blotting. Co-treatment with the PGRMC1 inhibitor AG205 (20 μM) blocked the inhibitory effects of 100 nM estradiol-17β and the GPER agonist, G-1, on spontaneous maturation of denuded zebrafish oocytes. Moreover, reversal of these estrogen effects on OM by the EGFR inhibitors AG1478 and AG825 (50 μM) was prevented by co-incubation with the PGRMC1 inhibitor. Inhibition of Pgrmc1 signaling with AG205 also caused a decrease in Egfr-dependent signaling and Egfr expression on oocyte cell membranes. These results indicate that maintenance of Pgrmc1 signaling is required for Egfr expression on zebrafish oocyte cell membranes and for conserving the functions of Egfr in maintaining meiotic arrest through estrogen activation of Gper.

scholarly journals Identification of Amino Acid Residues in Human IgM Fc Receptor (FcµR) Critical for IgM Binding

2021 ◽  
Vol 11 ◽  
Author(s):  
Christopher M. Skopnik ◽  
Khlowd Al-Qaisi ◽  
Rosaleen A. Calvert ◽  
Philipp Enghard ◽  
Andreas Radbruch ◽  
...  
Keyword(s):  
Amino Acid ◽  
Plasma Membranes ◽  
Surface Expression ◽  
Fc Receptor ◽  
Receptor Expression ◽  
Cell Surface Expression ◽  
Binding Potential ◽  
Amino Acid Residues ◽  
Modeling Analysis ◽  
The Difference

Both non-immune “natural” and antigen-induced “immune” IgM are important for protection against infections and for regulation of immune responses to self-antigens. The roles of its Fc receptor (FcµR) in these IgM effector functions have begun to be explored. In the present study, by taking advantage of the difference in IgM-ligand binding of FcµRs of human (constitutive binding) and mouse (transient binding), we replaced non-conserved amino acid residues of human FcµR with mouse equivalents before establishment of cell lines stably expressing mutant or wild-type (WT) receptors. The resultant eight-different mutant FcµR-bearing cells were compared with WT receptor-bearing cells for cell-surface expression and IgM-binding by flow cytometric assessments using receptor-specific mAbs and IgM paraproteins as ligands. Three sites Asn66, Lys79-Arg83, and Asn109, which are likely in the CDR2, DE loop and CDR3 of the human FcµR Ig-like domain, respectively, were responsible for constitutive IgM binding. Intriguingly, substitution of Glu41 and Met42 in the presumed CDR1 with the corresponding mouse residues Gln and Leu, either single or more prominently in combination, enhanced both the receptor expression and IgM binding. A four-aa stretch of Lys24-Gly27 in the predicted A ß-strand of human FcµR appeared to be essential for maintenance of its proper receptor conformation on plasma membranes because of reduction of both receptor expression and IgM-binding potential when these were mutated. Results from a computational structural modeling analysis were consistent with these mutational data and identified a possible mode of binding of FcµR with IgM involving the loops including Asn66, Arg83 and Asn109 of FcµR interacting principally with the Cµ4 domain including Gln510 and to a lesser extent Cµ3 domain including Glu398, of human IgM. To our knowledge, this is the first experimental report describing the identification of amino acid residues of human FcµR critical for binding to IgM Fc.

scholarly journals AS160 Associates with the Na+,K+-ATPase and Mediates the Adenosine Monophosphate-stimulated Protein Kinase-dependent Regulation of Sodium Pump Surface Expression

2010 ◽  
Vol 21 (24) ◽  
pp. 4400-4408 ◽  
Author(s):  
Daiane S. Alves ◽  
Glen A. Farr ◽  
Patricia Seo-Mayer ◽  
Michael J. Caplan
Keyword(s):  
Protein Kinase ◽  
Plasma Membranes ◽  
Sodium Pump ◽  
Adenosine Monophosphate ◽  
Cell Types ◽  
Surface Expression ◽  
Cell Surface Expression ◽  
Rab Gtpase ◽  
Α Subunit ◽  
Compound C

The Na+,K+-ATPase is the major active transport protein found in the plasma membranes of most epithelial cell types. The regulation of Na+,K+-ATPase activity involves a variety of mechanisms, including regulated endocytosis and recycling. Our efforts to identify novel Na+,K+-ATPase binding partners revealed a direct association between the Na+,K+-ATPase and AS160, a Rab-GTPase-activating protein. In COS cells, coexpression of AS160 and Na+,K+-ATPase led to the intracellular retention of the sodium pump. We find that AS160 interacts with the large cytoplasmic NP domain of the α-subunit of the Na+,K+-ATPase. Inhibition of the activity of the adenosine monophosphate-stimulated protein kinase (AMPK) in Madin-Darby canine kidney cells through treatment with Compound C induces Na+,K+-ATPase endocytosis. This effect of Compound C is prevented through the short hairpin RNA-mediated knockdown of AS160, demonstrating that AMPK and AS160 participate in a common pathway to modulate the cell surface expression of the Na+,K+-ATPase.

scholarly journals Cell surface expression of 4 β-galactosyltransferase accompanies rat parotid gland hypertrophy induced by changes in diet

1987 ◽  
Vol 246 (2) ◽  
pp. 387-391 ◽  
Author(s):  
M G Humphreys-Beher ◽  
C A Schneyer
Keyword(s):  
Cell Surface ◽  
Parotid Gland ◽  
Plasma Membranes ◽  
Specific Activity ◽  
Fold Increase ◽  
Surface Expression ◽  
Subcellular Fractionation ◽  
Cell Surface Expression ◽  
Intact Cells ◽  
Rat Parotid

Maintenance of rats for 2 weeks on a diet consisting of 50% inert cellulose and 50% laboratory chow resulted in hypertrophy of the parotid gland and a 4-fold increase in total membrane-associated 4 beta-galactosyltransferase enzyme activity (EC 2.4.1.38). Localization of the increased specific activity to the cell surface of the enlarged gland was shown by subcellular fractionation of Golgi and plasma membranes. This observation was confirmed by enzyme assays of intact cells; quantification of immunofluorescence was made by using a fluorescence activated cell sorter. Parotid gland hypertrophy was inhibited by the administration of the specific modifier protein alpha-lactalbumin as well as by a monospecific antibody for 4 beta-galactosyltransferase. These agents also inhibited the incorporation of thymidine into DNA.

scholarly journals Regulation of Kir4.1 and AQP4 expression and stability at the basolateral domain of epithelial MDCK cells by the extracellular matrix

2011 ◽  
Vol 301 (2) ◽  
pp. F396-F409 ◽  
Author(s):  
Daniel Kai Long Tham ◽  
Hakima Moukhles
Keyword(s):  
Extracellular Matrix ◽  
Epithelial Cells ◽  
Cell Surface ◽  
Mdck Cells ◽  
Surface Expression ◽  
Laminin Receptor ◽  
Cell Surface Expression ◽  
Αvβ3 Integrin ◽  
Diffusion Rates ◽  
Laminin 1

The proper targeting of ion channels to specialized domains is crucial for cell function. Kir4.1, the inwardly rectifying potassium channel, and aquaporin-4 (AQP4), the type 4 water-permeable channel, are localized at the basolateral domain of polarized epithelial cells; however, the mechanisms involved in their localization have yet to be determined. In this study, we investigated the role of the extracellular matrix in the localization of these channels in polarized Madin-Darby canine kidney (MDCK) cells. MDCK cells expressing green fluorescent protein-Kir4.1 or -AQP4 were cultured on laminin-1 or fibronectin and examined by confocal microscopy and cell surface biotinylation to assess plasma membrane expression of Kir4.1 and AQP4. Our data show that laminin-1 and fibronectin induce a significant increase in cell surface expression of both channels at the basolateral domain. Using fluorescence recovery after photobleaching, we demonstrate that laminin-1 and fibronectin reduce the diffusion rates of these channels. Finally, we show that the laminin receptor dystroglycan is important for cell surface expression of Kir4.1 but not AQP4. However, laminin-1 increases cell surface expression of both channels in cells deficient for dystroglycan, indicating that other receptors are involved. Indeed, RGD-containing peptides, which inhibit fibronectin binding to certain integrins, prevent the fibronectin-induced increase in Kir4.1 and AQP4 cell surface expression and reverse the laminin- and fibronectin-induced reduction in both channels' diffusion rates. Similarly, the αvβ3-integrin function-blocking antibody alters the reduction of AQP4 diffusion rates induced by both laminin and fibronectin, suggesting that αvβ3-integrin plays a role in the stabilization of APQ4 at the basolateral domain of epithelial cells.

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