scholarly journals Glycosylphosphatidylinositol-Anchored Cell Surface Proteins Regulate Position-Specific Cell Affinity in the Limb Bud

1998 ◽  
Vol 202 (2) ◽  
pp. 244-252 ◽  
Author(s):  
Naoyuki Wada ◽  
Ichiro Kimura ◽  
Hideaki Tanaka ◽  
Hiroyuki Ide ◽  
Tsutomu Nohno
Keyword(s):  
Cell Surface ◽  
Surface Proteins ◽  
Limb Bud ◽  
Specific Cell ◽  
Cell Surface Proteins ◽  
Cell Affinity

Mechanism of antibody stimulation of hexose transport in rat myoblasts

1984 ◽  
Vol 62 (5) ◽  
pp. 255-265 ◽  
Author(s):  
Theodore C. Y. Lo ◽  
Vincent Duronio
Keyword(s):  
Cell Surface ◽  
Covalent Modification ◽  
Membrane Receptors ◽  
Surface Proteins ◽  
Specific Cell ◽  
Activation Process ◽  
Hexose Transport ◽  
Antibody Treatment ◽  
Cell Surface Proteins ◽  
Membrane Components

We have recently demonstrated that exposure of rat myoblasts to anti-rat myoblast antiserum results in two- to three-fold activation of hexose transport. The present communication reports the possible mechanism(s) by which specific antibody can bring about such activation. Studies with Fab and Fc fragments indicate that the binding of Fab to specific cell surface component(s) is not sufficient to trigger activation of hexose transport; the immunoglobulin G (IgG) mediated dimerization of membrane components is required for this process. Although cytochalasin D has no effect on hexose transport in control and antibody-treated cells, pretreatment of cells with this inhibitor prevents antibody-mediated activation of hexose transport. It may be inferred from this observation that proper disposition of membrane components is required for the dimerization of membrane receptors. Since this activation of hexose transport is an irreversible process, it is possible that covalent modification of membrane components may have occurred as a result of antibody treatment. Pretreatment of cells with ammonium chloride or methylamine is found to abolish the antibody-mediated activation of hexose transport, even though these inhibitors have no effect on hexose transport in control and antibody-treated cells. These inhibitors may be acting on transglutaminase and (or) on some other proteins involved in the activation process. Several lines of evidence suggest that limited proteolytic cleavage of membrane components may be involved in the antibody-mediated activation of hexose transport. First, pretreatment with several protease inhibitors prevents activation of hexose transport. Second, several cell surface proteins are missing in antibody-treated cells. Third, limited proteolysis of cell surface proteins with trypsin can also bring about activation of hexose transport. In view of the fact that proteolytic activity cannot be detected in various IgG and serum preparations, it seems likely that endogenous membrane associated proteases may be involved in this activation process.

scholarly journals Tetraspanins Associated With oxLDL and IgG Mediated Phagocytosis In Human U937 Macrophages

2021 ◽  
Author(s):  
Pardis Pakshir
Keyword(s):  
Cell Surface ◽  
Signaling Pathways ◽  
Laser Scanning ◽  
Laser Scanning Confocal Microscopy ◽  
Fc Receptor ◽  
Surface Proteins ◽  
Specific Cell ◽  
Cell Surface Proteins ◽  
Scanning Confocal Microscopy ◽  
Receptor Complexes

One of the crucial key targets in treatment of diseases are cell surface proteins, such as receptor complexes, and their associated signaling pathways. The Fc receptor is one of the most important phagocytic receptors of the cells of immune system. The ligand of the Fc gamma receptor is immunoglobulin G (IgG), which triggers the engulfment of foreign molecules coated by antibodies by a process called phagocytosis. A Specialized subset of cells including macrophages engulfs foreign particles by the Fc receptor. Another phagocytic receptor of macrophages is the CD36 receptor, which binds the ligand oxLDL and is known to be involved in the development of atherosclerotic lesions in the arteries. A few members of the Tetraspanin proteins have been found to be associated with theses receptors in macrophages. Tetraspanins may act as “molecular facilitators” grouping specific cell-surface proteins and thus increasing the formation and stability of functional signaling complexes. There is a significant amount of research done on the receptors of the surface of macrophages, however, the proteins associated with these receptors, their potential signaling pathways and the mechanisms involved are not yet fully understood. This thesis aims to investigate the presence and potential functional role of the specific Tetraspanin isoforms in Fc and CD36 mediated phagocytosis. Silencing RNA, quantitative assays of phagocytosis, and laser scanning confocal microscopy were used to test the phagocytic efficiency of macrophages in IgG and oxLDL mediated phagocytosis. Understanding the regulatory roles of Tetraspanins can provide insight into various immune diseases.

Generation of a Platform for Identification of CLL Specific Cell Surface Proteins Targeted by Anti-Tumor Antibodies in Patient Sera After Allogeneic Hematopoietic Cell Transplantion

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 1349-1349
Author(s):  
Brian C Shaffer ◽  
Judith Leitner ◽  
Adrian Wiestner ◽  
Michael R. Bishop ◽  
Steven Z. Pavletic ◽  
...  
Keyword(s):  
Cell Surface ◽  
Conflicts Of Interest ◽  
Lymphocytic Leukemia ◽  
Hematopoietic Cell ◽  
Surface Proteins ◽  
Unrelated Donor ◽  
Specific Cell ◽  
Serum Antibodies ◽  
Cell Surface Proteins ◽  
Specific Cell Surface

Abstract Abstract 1349 Background: Clinical and translational studies suggest that allogeneic hematopoietic cell transplantation (alloHCT) may induce production of anti-tumor antibodies in the recipient after transplantation. We hypothesized that this phenomenon can serve as a platform for the generation of novel therapeutic monoclonal antibodies (mAbs). An important step to this goal is the identification of targeted antigens with defined ability to support antibody induced cell death. To address this challenge, we developed a chronic lymphocytic leukemia (CLL) membrane protein display system capable of discovering cell surface proteins targeted by serum antibodies and applied this tool to post-alloHCT patient samples. Methods: Total and mRNA was purified from peripheral blood mononuclear cells from six untreated CLL patients and used to generate cDNA. The patient cDNA was pooled, cloned into the retroviral vector pBMN, and expressed in the murine T-cell line Bw 5147 (Bw-CLL-Lib). Enrichment of Bw-CLL-Lib cells displaying membrane proteins of interest was performed via fluorescence activated cell sorting. The unselected Bw-CLL-Lib pool was blocked with recombinant human Fc followed by staining with 1:200 diluted post-alloHCT patient sera and by secondary staining with pooled Alexa Fluor 647 labeled goat-anti-human-lambda and -anti-kappa light chain specific antibodies. Bw-CLL-Lib cells positively binding to serum antibodies were collected and re-grown in culture to 1×106 cells. A second round of enrichment was performed, after which the Bw-CLL-Lib cells were placed in limiting dilution culture. Individual clones were screened for serum reactivity and the retroviral inserts in reactive Bw-CLL-Lib clones were rescued via PCR and sequenced. Proteins of interest were re-expressed in Bw 5147 cells and used to confirm reactivity of the patient serum with specific cell surface proteins. Results: The Bw-CLL-Lib cell pool was screened separately with serum from ten patients with CLL post unrelated donor alloHCT. Serum from three patients enriched positively binding Bw-CLL-Lib clones. Thus far, we have successfully identified serum antibodies to a membrane proximal epitope on a therapeutically relevant CLL cell surface protein. Conclusions: Here we demonstrate a methodology for identifying targets of anti-tumor antibodies in serum from patients after alloHCT. This technique yields a high degree of successful identification of antibody reactivity with cell surface proteins in post alloHCT serum samples. When combined with post-alloHCT antibody Fab phage display (Baskar et al., Blood 114, 4494–4502, 2009) this methodology forms a complete drug and target discovery platform for the generation of tumor specific mAbs derived from alloHCT patients. Disclosures: No relevant conflicts of interest to declare.

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.

Disruption of pioneer growth cone guidance in vivo by removal of glycosyl-phosphatidylinositol-anchored cell surface proteins

Development ◽  
1992 ◽  
Vol 114 (2) ◽  
pp. 507-519 ◽  
Author(s):  
W.S. Chang ◽  
K. Serikawa ◽  
K. Allen ◽  
D. Bentley
Keyword(s):  
Cell Surface ◽  
Growth Cone ◽  
Growth Cones ◽  
Surface Proteins ◽  
Limb Bud ◽  
Cell Surface Proteins ◽  
Glycosyl Phosphatidylinositol ◽  
Stage Of Development ◽  
Growth Cone Guidance

Cell surface proteins anchored to membranes via covalently attached glycosyl-phosphatidylinositol (GPI) have been implicated in neuronal adhesion, promotion of neurite outgrowth and directed cell migration. Treatment of grasshopper embryos with bacterial phosphatidylinositol-specific phospholipase C (PI-PLC), an enzyme that cleaves the GPI anchor, often induced disruptions in the highly stereotyped migrations of peripheral pioneer growth cones and afferent neuron cell bodies. In distal limb regions of embryos treated with PI-PLC at early stages of pioneer axon outgrowth, growth cones lost their proximal orientation toward the central nervous system (CNS) and turned distally. Pioneer growth cones in treated limbs also failed to make a characteristic ventral turn along the trochanter-coxa (Tr-Cx) segment boundary, and instead continued to grow proximally across the boundary. Treatment at an earlier stage of development caused pre-axonogenesis Cx1 neurons to abandon their normal circumferential migration and reorient toward the CNS. None of these abnormal phenotypes were observed in limbs of untreated embryos or embryos exposed to other phospholipases that do not release GPI-anchored proteins. Incubation of embryos with PI-PLC effectively removed immunoreactivity for fasciclin I, a GPI-anchored protein expressed on a subset of neuronal surfaces. These results suggest that cell surface GPI-anchored proteins are involved in pioneer growth cone guidance and in pre-axonogenesis migration of neurons in the grasshopper limb bud in vivo.

scholarly journals Tetraspanins Associated With oxLDL and IgG Mediated Phagocytosis In Human U937 Macrophages

2021 ◽  
Author(s):  
Pardis Pakshir
Keyword(s):  
Cell Surface ◽  
Signaling Pathways ◽  
Laser Scanning ◽  
Laser Scanning Confocal Microscopy ◽  
Fc Receptor ◽  
Surface Proteins ◽  
Specific Cell ◽  
Cell Surface Proteins ◽  
Scanning Confocal Microscopy ◽  
Receptor Complexes

One of the crucial key targets in treatment of diseases are cell surface proteins, such as receptor complexes, and their associated signaling pathways. The Fc receptor is one of the most important phagocytic receptors of the cells of immune system. The ligand of the Fc gamma receptor is immunoglobulin G (IgG), which triggers the engulfment of foreign molecules coated by antibodies by a process called phagocytosis. A Specialized subset of cells including macrophages engulfs foreign particles by the Fc receptor. Another phagocytic receptor of macrophages is the CD36 receptor, which binds the ligand oxLDL and is known to be involved in the development of atherosclerotic lesions in the arteries. A few members of the Tetraspanin proteins have been found to be associated with theses receptors in macrophages. Tetraspanins may act as “molecular facilitators” grouping specific cell-surface proteins and thus increasing the formation and stability of functional signaling complexes. There is a significant amount of research done on the receptors of the surface of macrophages, however, the proteins associated with these receptors, their potential signaling pathways and the mechanisms involved are not yet fully understood. This thesis aims to investigate the presence and potential functional role of the specific Tetraspanin isoforms in Fc and CD36 mediated phagocytosis. Silencing RNA, quantitative assays of phagocytosis, and laser scanning confocal microscopy were used to test the phagocytic efficiency of macrophages in IgG and oxLDL mediated phagocytosis. Understanding the regulatory roles of Tetraspanins can provide insight into various immune diseases.

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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