scholarly journals Nuclear Translocation of fibroblast growth factor (FGF) receptors in response to FGF-2.

1996 ◽  
Vol 134 (2) ◽  
pp. 529-536 ◽  
Author(s):  
P A Maher
Keyword(s):  
Cell Surface ◽  
Nuclear Translocation ◽  
Cell Types ◽  
Surface Proteins ◽  
Nuclear Fraction ◽  
Fgf Receptor ◽  
Quiescent Cells ◽  
3T3 Fibroblasts ◽  
Different Cell Types ◽  
Dose Dependent Increase

Members of the FGF family of growth factors localize to the nuclei in a variety of different cell types. To determine whether FGF receptors are also present within nuclei and if this localization is regulated by FGFs, nuclei were prepared from quiescent and FGF-2-treated Swiss 3T3 fibroblasts and examined for the presence of FGF receptors by immunoblotting with an antibody produced against the extracellular domain of FGF receptor-1 (FGFR-1). Little or no FGFR-1 is detected in nuclei prepared from quiescent cells. When cells are treated with FGF-2, however, there is a time- and dose-dependent increase in the association of FGFR-1 immunoreactivity with the nucleus. In contrast, treatment with either EGF or 10% serum does not increase the association of FGFR-1 with the nucleus. When cell surface proteins are labeled with biotin, a biotinylated FGFR-1 is detected in the nuclear fraction prepared from FGF-2-treated, but not untreated, cells indicating that the nuclear-associated FGFR-1 immunoreactivity derives from the cell surface. The presence of FGFR-1 in the nuclei of FGF-2-treated cells was confirmed by immunostaining with a panel of different FGFR-1 antibodies, including one directed against the COOH-terminal domain of the protein. Fractionation of nuclei from FGF-2-treated cells indicates that nuclear FGFR-1 is localized to the nuclear matrix, suggesting that the receptor may play a role in regulating gene activity.

Tetraspanins and malignancy

2001 ◽  
Vol 3 (4) ◽  
pp. 1-17 ◽  
Author(s):  
Claude Boucheix ◽  
Guy Huynh Thien Duc ◽  
Claude Jasmin ◽  
Eric Rubinstein
Keyword(s):  
Cell Adhesion ◽  
Cell Surface ◽  
Tumour Progression ◽  
Metastatic Potential ◽  
Cell Types ◽  
Surface Proteins ◽  
Surface Complexes ◽  
Physiological Importance ◽  
Biochemical Mechanisms ◽  
Different Cell Types

Tetraspanins, also called tetraspans or the transmembrane 4 superfamily (TM4SF), are cell-surface proteins that span the membrane four times and are found on many different cell types in many organisms. They display numerous properties that indicate their physiological importance in cell adhesion, motility, activation and proliferation, as well as their contribution to pathological conditions such as metastasis or viral infection. A major characteristic of tetraspanins is their ability to form cell-surface complexes with other molecules participating in cell adhesion, either to the extracellular matrix (ECM) or to other cells, and with molecules required for signalling. It is not yet known how the structure of the complexes might affect the functions of other molecules or what basic biochemical mechanisms allow their formation and regulation. Nevertheless, an intriguing association between tetraspanin expression and metastatic potential indicates that these molecules may provide novel insights into tumour progression.

The E-selectin-ligand ESL-1 is located in the Golgi as well as on microvilli on the cell surface

1997 ◽  
Vol 110 (6) ◽  
pp. 687-694 ◽  
Author(s):  
M. Steegmaier ◽  
E. Borges ◽  
J. Berger ◽  
H. Schwarz ◽  
D. Vestweber
Keyword(s):  
Flow Cytometry ◽  
Cell Surface ◽  
Surface Proteins ◽  
Intact Cells ◽  
Fgf Receptor ◽  
Cell Surface Biotinylation ◽  
Cell Surface Staining ◽  
Surface Staining ◽  
Selectin Ligand ◽  
Golgi Protein

Neutrophils and subsets of lymphocytes bind to E-selectin, a cytokine inducible adhesion molecule on endothelial cells. The E-selectin-ligand-1 (ESL-1) is a high affinity glycoprotein ligand which participates in the binding of mouse myeloid cells to E-selectin. The sequence of mouse ESL-1 is highly homologous to the cysteine rich FGF receptor (CFR) in chicken and the rat Golgi protein MG160. We have analysed the subcellular distribution of ESL-1 by indirect immunofluorescence, flow cytometry, various biochemical techniques and by immunogold scanning electron microscopy. We could localize ESL-1 in the Golgi as well as on the cell surface of 32Dc13 cells and neutrophils. Cell surface staining was confirmed by cell surface biotinylation and by cell surface immunoprecipitations in which antibodies only had access to surface proteins on intact cells. In addition, ESL-1(high) and ESL-1(low) expressing cells, sorted by flow cytometry, gave rise to high and low immunoprecipitation signals for ESL-1, respectively. Based on immunogold labeling of intact cells, we localized ESL-1 on microvilli of 32Dc13 cells and of the lymphoma cell line K46. Quantitative evaluation determined 80% of the total labeling for ESL-1 on microvilli of K46 cells while 69% of the labeling for the control antigen B220 was found on the planar cell surface. These data indicate that ESL-1 occurs at sites on the leukocyte cell surface which are destined for the initiation of cell contacts to the endothelium.

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 Reticulon 4a promotes exocytosis in mammalian cells

2019 ◽  
Vol 30 (18) ◽  
pp. 2349-2357 ◽  
Author(s):  
Richik Nilay Mukherjee ◽  
Daniel L. Levy
Keyword(s):  
Cell Surface ◽  
Protein Trafficking ◽  
Mammalian Cells ◽  
Cell Types ◽  
Vesicular Trafficking ◽  
Secreted Proteins ◽  
Mammalian Cell Lines ◽  
Rough Er ◽  
Different Cell Types ◽  
Functional Output

Endoplasmic reticulum (ER) tubules and sheets conventionally correspond to smooth and rough ER, respectively. The ratio of ER tubules-to-sheets varies in different cell types and changes in response to cellular conditions, potentially impacting the functional output of the ER. To directly test whether ER morphology impacts vesicular trafficking, we increased the tubule-to-sheet ratio in three different ways, by overexpressing Rtn4a, Rtn4b, or REEP5. Only Rtn4a overexpression increased exocytosis, but not overall levels, of several cell surface and secreted proteins. Furthermore, Rtn4a depletion reduced cell surface trafficking without affecting ER morphology. Similar results were observed in three different mammalian cell lines, suggesting that Rtn4a generally enhances exocytosis independently of changes in ER morphology. Finally, we show that Rtn4a levels modulate cell adhesion, possibly by regulating trafficking of integrins to the cell surface. Taking the results together, we find that altering ER morphology does not necessarily affect protein trafficking, but that Rtn4a specifically enhances exocytosis.

scholarly journals Posttranslational Modifications Required for Cell Surface Localization and Function of the Fungal Adhesin Aga1p

2003 ◽  
Vol 2 (5) ◽  
pp. 1099-1114 ◽  
Author(s):  
Guohong Huang ◽  
Mingliang Zhang ◽  
Scott E. Erdman
Keyword(s):  
Cell Wall ◽  
Cell Surface ◽  
Posttranslational Modifications ◽  
Transmembrane Domain ◽  
Signal Sequence ◽  
Cell Types ◽  
Fungal Species ◽  
Surface Proteins ◽  
Functional Requirements

ABSTRACT Adherence of fungal cells to host substrates and each other affects their access to nutrients, sexual conjugation, and survival in hosts. Adhesins are cell surface proteins that mediate these different cell adhesion interactions. In this study, we examine the in vivo functional requirements for specific posttranslational modifications to these proteins, including glycophosphatidylinositol (GPI) anchor addition and O-linked glycosylation. The processing of some fungal GPI anchors, creating links to cell wall β-1,6 glucans, is postulated to facilitate postsecretory traffic of proteins to cell wall domains conducive to their functions. By studying the yeast sexual adhesin subunit Aga1p, we found that deletion of its signal sequence for GPI addition eliminated its activity, while deletions of different internal domains had various effects on function. Substitution of the Aga1p GPI signal domain with those of other GPI-anchored proteins, a single transmembrane domain, or a cysteine capable of forming a disulfide all produced functional adhesins. A portion of the cellular pool of Aga1p was determined to be cell wall resident. Aga1p and the α-agglutinin Agα1p were shown to be under glycosylated in cells lacking the protein mannosyltransferase genes PMT1 and PMT2, with phenotypes manifested only in MATα cells for single mutants but in both cell types when both genes are absent. We conclude that posttranslational modifications to Aga1p are necessary for its biogenesis and activity. Our studies also suggest that in addition to GPI-glucan linkages, other cell surface anchorage mechanisms, such as transmembrane domains or disulfides, may be employed by fungal species to localize adhesins.

scholarly journals Phosphorylation and internalization of gp130 occur after IL-6 activation of Jak2 kinase in hepatocytes.

1994 ◽  
Vol 5 (7) ◽  
pp. 819-828 ◽  
Author(s):  
Y Wang ◽  
G M Fuller
Keyword(s):  
Protein Synthesis ◽  
Cell Surface ◽  
De Novo ◽  
Cell Types ◽  
Surface Expression ◽  
Cell Surface Expression ◽  
Protein Synthesis Inhibitors ◽  
Different Cell Types ◽  
Kinetics Of

Recent evidence has shown that members of the Jak kinase family are activated after IL-6 binds to its receptor complex, leading to a tyrosine phosphorylation of gp130, the IL-6 signal-transducing subunit. The different members of the IL-6 cytokine subfamily induce distinct patterns of Jak-Tyk phosphorylation in different cell types. Using monospecific antibodies to gp130, Jak2 kinase, and phosphotyrosine, we investigated the kinetics of IL-6 stimulation of members of this pathway in primary hepatocytes. Our findings show that Jak 2 is maximally activated within 2 min of exposure to IL-6, followed by gp130 phosphorylation that reaches its peak in another 2 min then declines to basal level by 60 min. In vitro phosphorylation experiments show that activated Jak 2 is able to phosphorylate both native gp130 and a fusion peptide containing its cytoplasmic domain, demonstrating gp130 is a direct substrate of Jak 2 kinase. Experiments designed to explore the cell surface expression of gp130 show that > or = 2 h are required to get a second round of phosphorylation after the addition of more cytokines. This finding suggests that activated gp130 is internalized from the cell surface after IL-6 stimulation. Additional experiments using protein synthesis inhibitors reveal that new protein synthesis is required to get a second cycle of gp130 phosphorylation indicating gp130 must be synthesized de novo and inserted into the membrane. These findings provide strong evidence that down regulation of the IL-6 signal in hepatocytes involves the internalization and cytosol degradation of gp130.

scholarly journals Significance of Nano- and Microtopography for Cell-Surface Interactions in Orthopaedic Implants

2007 ◽  
Vol 2007 ◽  
pp. 1-19 ◽  
Author(s):  
M. Jäger ◽  
C. Zilkens ◽  
K. Zanger ◽  
R. Krauspe
Keyword(s):  
Cell Surface ◽  
Cell Types ◽  
Surface Interactions ◽  
Orthopaedic Implants ◽  
Nanostructured Surfaces ◽  
Major Interest ◽  
Cell Surface Interactions ◽  
Biomaterial Application ◽  
Different Cell Types

Cell-surface interactions play a crucial role for biomaterial application in orthopaedics. It is evident that not only the chemical composition of solid substances influence cellular adherence, migration, proliferation and differentiation but also the surface topography of a biomaterial. The progressive application of nanostructured surfaces in medicine has gained increasing interest to improve the cytocompatibility and osteointegration of orthopaedic implants. Therefore, the understanding of cell-surface interactions is of major interest for these substances. In this review, we elucidate the principle mechanisms of nano- and microscale cell-surface interactions in vitro for different cell types onto typical orthopaedic biomaterials such as titanium (Ti), cobalt-chrome-molybdenum (CoCrMo) alloys, stainless steel (SS), as well as synthetic polymers (UHMWPE, XLPE, PEEK, PLLA). In addition, effects of nano- and microscaled particles and their significance in orthopaedics were reviewed. The significance for the cytocompatibility of nanobiomaterials is discussed critically.

Direct linkage of thrombin to its cell surface receptors in different cell types

1979 ◽  
Vol 12 (2) ◽  
pp. 245-257 ◽  
Author(s):  
Robert L. Simmer ◽  
Joffre B. Baker ◽  
Dennis D. Cunningham
Keyword(s):  
Cell Surface ◽  
Cell Types ◽  
Cell Surface Receptors ◽  
Surface Receptors ◽  
Direct Linkage ◽  
Different Cell Types

scholarly journals Hyaluronan as an Immune Regulator in Human Diseases

2011 ◽  
Vol 91 (1) ◽  
pp. 221-264 ◽  
Author(s):  
Dianhua Jiang ◽  
Jiurong Liang ◽  
Paul W. Noble
Keyword(s):  
Cell Surface ◽  
Tissue Injury ◽  
Inflammatory Cells ◽  
Cell Types ◽  
Surface Proteins ◽  
Human Diseases ◽  
Inflammatory Genes ◽  
Extracellular Matrix Components ◽  
Injury And Repair

Accumulation and turnover of extracellular matrix components are the hallmarks of tissue injury. Fragmented hyaluronan stimulates the expression of inflammatory genes by a variety of immune cells at the injury site. Hyaluronan binds to a number of cell surface proteins on various cell types. Hyaluronan fragments signal through both Toll-like receptor (TLR) 4 and TLR2 as well as CD44 to stimulate inflammatory genes in inflammatory cells. Hyaluronan is also present on the cell surface of epithelial cells and provides protection against tissue damage from the environment by interacting with TLR2 and TLR4. Hyaluronan and hyaluronan-binding proteins regulate inflammation, tissue injury, and repair through regulating inflammatory cell recruitment, release of inflammatory cytokines, and cell migration. This review focuses on the role of hyaluronan as an immune regulator in human diseases.

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