scholarly journals Interaction of single-chain urokinase with its receptor induces the appearance and disappearance of binding epitopes within the resultant complex for other cell surface proteins

Blood ◽  
1996 ◽  
Vol 88 (2) ◽  
pp. 542-551 ◽  
Author(s):  
AA Higazi ◽  
RH Upson ◽  
RL Cohen ◽  
J Manuppello ◽  
J Bognacki ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Cell Surface ◽  
Binding Sites ◽  
Ldl Receptor ◽  
Cell Types ◽  
Surface Proteins ◽  
Single Chain ◽  
Cell Surface Proteins ◽  
Functional Changes ◽  
And Migration

Binding of urokinase-type plasminogen activator (uPA) to its glycosylphosphatidylinositol-anchored receptor (uPAR) initiates signal transduction, adhesion, and migration in certain cell types. To determine whether some of these activities may be mediated by associations between the uPA/uPAR complex and other cell surface proteins, we studied the binding of complexes composed of recombinant, soluble uPA receptor (suPAR) and single chain uPA (scuPA) to a cell line (LM-TK- fibroblasts) that does not express glycosylphosphatidylinositol (GPI)-anchored proteins to eliminate potential competition by endogenous uPA receptors. scuPA induced the binding of suPAR to LM-TK- cells. Binding of labeled suPAR/scuPA was inhibited by unlabeled complex, but not by scuPA or suPAR added separately, indicating cellular binding sites had been formed that are not present in either component. Binding of the complex was inhibited by low molecular weight uPA (LMW-uPA) indicating exposure of an epitope found normally in the isolated B chain of two chain uPA (tcuPA), but hidden in soluble scuPA. Binding of LMW-uPA was independent of its catalytic site and was associated with retention of its enzymatic activity. Additional cell binding epitopes were generated within suPAR itself by the aminoterminal fragment of scuPA, which itself does not bind to LM-TK- cells. When scuPA bound to suPAR, a binding site for alpha 2-macroglobulin receptor/LDL receptor-related protein (alpha 2 MR/LRP) was lost, while binding sites for cell-associated vitronectin and thrombospondin were induced. In accord with this, the internalization and degradation of cell-associated tcuPA and tcuPA-PAI- 1 complexes proceeded less efficiently in the presence of suPAR. Further, little degradation of suPAR was detected, suggesting that cell- bound complex dissociated during the initial stages of endocytosis. Thus, the interaction of scuPA with its receptor causes multiple functional changes within the complex including the dis-appearance of an epitope in scuPA involved in its clearance from the cell surface and the generation of novel epitopes that promote its binding to proteins involved in cell adhesion and signal transduction.

scholarly journals Prediction of the Secretome and the Surfaceome: A Strategy to Decipher the Crosstalk between Adipose Tissue and Muscle during Fetal Growth

2020 ◽  
Vol 21 (12) ◽  
pp. 4375
Author(s):  
Muriel Bonnet ◽  
Nicolas Kaspric ◽  
Kimberly Vonnahme ◽  
Didier Viala ◽  
Christophe Chambon ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Cell Surface ◽  
Fetal Growth ◽  
Protein Interactions ◽  
Cell Types ◽  
Surface Proteins ◽  
Protein Protein Interactions ◽  
Cell Surface Proteins ◽  
Bovine Fetuses ◽  
Muscular Tissues

Crosstalk between adipose and muscular tissues is hypothesized to regulate the number of muscular and adipose cells during fetal growth, with post-natal consequences on lean and fat masses. Such crosstalk largely remains, however, to be described. We hypothesized that a characterization of the proteomes of adipose and muscular tissues from bovine fetuses may enhance the understanding of the crosstalk between these tissues through the prediction of their secretomes and surfaceomes. Proteomic experiments have identified 751 and 514 proteins in fetal adipose tissue and muscle. These are mainly involved in the regulation of cell proliferation or differentiation, but also in pathways such as apoptosis, Wnt signalling, or cytokine-mediated signalling. Of the identified proteins, 51 adipokines, 11 myokines, and 37 adipomyokines were predicted, together with 26 adipose and 13 muscular cell surface proteins. Analysis of protein–protein interactions suggested 13 links between secreted and cell surface proteins that may contribute to the adipose–muscular crosstalk. Of these, an interaction between the adipokine plasminogen and the muscular cell surface alpha-enolase may regulate the fetal myogenesis. The in silico secretome and surfaceome analyzed herein exemplify a powerful strategy to enhance the elucidation of the crosstalk between cell types or tissues.

scholarly journals Erratum: Corrigendum: Fluorogen-activating single-chain antibodies for imaging cell surface proteins

2008 ◽  
Vol 26 (4) ◽  
pp. 470-470 ◽  
Author(s):  
Christopher Szent-Gyorgyi ◽  
Brigitte A Schmidt ◽  
Yehuda Creeger ◽  
Gregory W Fisher ◽  
Kelly L Zakel ◽  
...  
Keyword(s):  
Cell Surface ◽  
Surface Proteins ◽  
Single Chain ◽  
Cell Surface Proteins ◽  
Single Chain Antibodies

scholarly journals Society Medal and Awards Winners for 2006

2005 ◽  
Vol 27 (4) ◽  
pp. 57-60
Keyword(s):  
Cell Surface ◽  
B Lymphocytes ◽  
Cell Types ◽  
Surface Antigens ◽  
Surface Proteins ◽  
Specific Cell ◽  
Cell Surface Antigens ◽  
Cell Surface Proteins ◽  
Extracellular Signals ◽  
Proliferation And Differentiation

Congratulations go to the following scientists who will be recipients of the Society's Awards in 2006. use antibodies against cell-surface antigens to distinguish and separate T- and B-lymphocytes and to show that antibody binding causes a redistribution and endocytosis of cell-surface proteins. He has studied the intracellular programmes and extracellular signals that control the survival, growth, proliferation and differentiation of specific cell types of the developing rodent nervous system.

Interaction of Lp(a) with Plasminogen Binding Sites on Cells

1995 ◽  
Vol 73 (03) ◽  
pp. 458-465 ◽  
Author(s):  
Lindsey A Miles ◽  
Gunther M Fless ◽  
Angelo M Scanu ◽  
Patricia Baynham ◽  
Matthew T Sebald ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Cell Surface ◽  
Binding Sites ◽  
Surface Proteins ◽  
Time Dependent ◽  
Temperature Sensitive ◽  
U937 Cells ◽  
Cell Surface Proteins ◽  
Sensitive Characteristics ◽  
Lipoprotein Binding

SummaryLp(a) competes with plasminogen for binding to cells but it is not known whether this competition is due to the ability of Lp(a) to interact directly with plasminogen receptors. In the present study, we demonstrate that Lp(a) can interact directly with plasminogen binding sites on monocytoid U937 cells and endothelial cells. The interaction of Lp(a) with these sites was time dependent, specific, saturable, divalent ion independent and temperature sensitive, characteristics of plasminogen binding to these sites. The affinity of plasminogen and Lp(a) for these sites also was similar (Kd = 1-3 μM), but Lp(a) bound to fewer sites (̴10-fold less). Both gangliosides and cell surface proteins with car- boxy-terminal lysyl residues, including enolase, a candidate plasminogen receptor, inhibited Lp(a) binding to U937 cells. Additionally, Lp(a) interacted with low affinity lipoprotein binding sites on these cells which also recognized LDL and HDL. The ability of Lp(a) to interact with sites on cells that recognize plasminogen may contribute to the pathogenetic consequences of high levels of circulating Lp(a).

Fluorogen-activating single-chain antibodies for imaging cell surface proteins

2007 ◽  
Vol 26 (2) ◽  
pp. 235-240 ◽  
Author(s):  
Christopher Szent-Gyorgyi ◽  
Brigitte F Schmidt ◽  
Yehuda Creeger ◽  
Gregory W Fisher ◽  
Kelly L Zakel ◽  
...  
Keyword(s):  
Cell Surface ◽  
Surface Proteins ◽  
Single Chain ◽  
Cell Surface Proteins ◽  
Single Chain Antibodies

What do nanometer molecular trajectories tell us about heterogeneous cell surface domaines?

1995 ◽  
Vol 53 ◽  
pp. 786-787
Author(s):  
Watt W. Webb
Keyword(s):  
Cell Surface ◽  
Lipid Membranes ◽  
Surface Proteins ◽  
Protein Diffusion ◽  
Coated Pits ◽  
Cell Surface Proteins ◽  
Membrane Heterogeneity ◽  
Fluorescence Photobleaching Recovery ◽  
Photobleaching Recovery ◽  
Plasma Membrane Heterogeneity

Plasma membrane heterogeneity is implicit in the existence of specialized cell surface organelles which are necessary for cellular function; coated pits, post and pre-synaptic terminals, microvillae, caveolae, tight junctions, focal contacts and endothelial polarization are examples. The persistence of these discrete molecular aggregates depends on localized restraint of the constituent molecules within specific domaines in the cell surface by strong intermolecular bonds and/or anchorage to extended cytoskeleton. The observed plasticity of many of organelles and the dynamical modulation of domaines induced by cellular signaling evidence evanescent intermolecular interactions even in conspicuous aggregates. There is also strong evidence that universal restraints on the mobility of cell surface proteins persist virtually everywhere in cell surfaces, not only in the discrete organelles. Diffusion of cell surface proteins is slowed by several orders of magnitude relative to corresponding protein diffusion coefficients in isolated lipid membranes as has been determined by various ensemble average methods of measurement such as fluorescence photobleaching recovery(FPR).

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