scholarly journals Immunological identification of a new 14X10(3) Mr membrane-bound protein in Torpedo electric organ

1991 ◽  
Vol 98 (3) ◽  
pp. 351-361
Author(s):  
N. Morel ◽  
G. Brochier ◽  
M. Synguelakis ◽  
G. Le Gal La Salle
Keyword(s):  
External Surface ◽  
Electric Organ ◽  
Cell Types ◽  
Immunogold Labelling ◽  
Electron Microscope Level ◽  
Capillary Endothelial Cells ◽  
Membrane Bound ◽  
Torpedo Electric Organ ◽  
Immunological Identification

A series of monoclonal antibodies binding to different epitopes shared by a 14 × 10(3)Mr membrane-bound polypeptide has been obtained. By indirect immuno-fluorescence, it was shown that the 14 × 10(3)Mr antigen is present in various cell types in Torpedo electric organ and muscle, especially fibroblasts, capillary endothelial cells, axonal cuff cells and, to a lesser extent, Schwann cells. At the electron-microscope level, after immunogold labelling, the antigen was found associated with the external surface of the plasma membrane of these cells, with the exception of the axonal cuff cells where part of the labelling was intracellular. The possible biological role of this 14 × 10(3)Mr protein is unknown but preliminary experiments suggest that this antigen has affinity for other Torpedo electric organ membrane proteins.

scholarly journals Large-scale purification of presynaptic plasma membranes from Torpedo marmorata electric organ.

1985 ◽  
Vol 101 (5) ◽  
pp. 1757-1762 ◽  
Author(s):  
N Morel ◽  
J Marsal ◽  
R Manaranche ◽  
S Lazereg ◽  
J C Mazie ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Large Scale ◽  
Plasma Membranes ◽  
Electric Organ ◽  
Acetylcholinesterase Activity ◽  
Cholinergic Nerve Terminals ◽  
Membrane Bound ◽  
Torpedo Electric Organ ◽  
Presynaptic Plasma Membrane ◽  
Glycera Convoluta

The presynaptic plasma membrane (PSPM) of cholinergic nerve terminals was purified from Torpedo electric organ using a large-scale procedure. Up to 500 g of frozen electric organ were fractioned in a single run, leading to the isolation of greater than 100 mg of PSPM proteins. The purity of the fraction is similar to that of the synaptosomal plasma membrane obtained after subfractionation of Torpedo synaptosomes as judged by its membrane-bound acetylcholinesterase activity, the number of Glycera convoluta neurotoxin binding sites, and the binding of two monoclonal antibodies directed against PSPM. The specificity of these antibodies for the PSPM is demonstrated by immunofluorescence microscopy.

scholarly journals Role of Cardiac A2A Receptors Under Normal and Pathophysiological Conditions

2021 ◽  
Vol 11 ◽  
Author(s):  
P. Boknik ◽  
J. Eskandar ◽  
B. Hofmann ◽  
N. Zimmermann ◽  
J. Neumann ◽  
...  
Keyword(s):  
Adenosine Receptors ◽  
Mammalian Species ◽  
Cell Types ◽  
Future Research ◽  
Research Needs ◽  
Transient Ischemia ◽  
A2a Receptors ◽  
Membrane Bound ◽  
Signal Transduction Systems

This review presents an overview of cardiac A2A-adenosine receptors The localization of A2A-AR in the various cell types that encompass the heart and the role they play in force regulation in various mammalian species are depicted. The putative signal transduction systems of A2A-AR in cells in the living heart, as well as the known interactions of A2A-AR with membrane-bound receptors, will be addressed. The possible role that the receptors play in some relevant cardiac pathologies, such as persistent or transient ischemia, hypoxia, sepsis, hypertension, cardiac hypertrophy, and arrhythmias, will be reviewed. Moreover, the cardiac utility of A2A-AR as therapeutic targets for agonistic and antagonistic drugs will be discussed. Gaps in our knowledge about the cardiac function of A2A-AR and future research needs will be identified and formulated.

scholarly journals Association of Blood Group Antigen CD59 with Disease

2022 ◽  
pp. 1-12
Author(s):  
Christof Weinstock
Keyword(s):  
Blood Group ◽  
Cell Clone ◽  
Membrane Attack Complex ◽  
Cell Types ◽  
Blood Group Antigen ◽  
Age Related Macular Degeneration ◽  
Age Related ◽  
Life Threatening ◽  
Membrane Bound

In 2014, the membrane-bound protein CD59 became a blood group antigen. CD59 has been known for decades as an inhibitor of the complement system, located on erythrocytes and on many other cell types. In paroxysmal nocturnal haemoglobinuria (PNH), a stem cell clone with acquired deficiency to express GPI-anchored molecules, including the complement inhibitor CD59, causes severe and life-threatening disease. The lack of CD59, which is the only membrane-bound inhibitor of the membrane attack complex, contributes a major part of the intravascular haemolysis observed in PNH patients. This crucial effect of CD59 in PNH disease prompted studies to investigate its role in other diseases. In this review, the role of CD59 in inflammation, rheumatic disease, and age-related macular degeneration is investigated. Further, the pivotal role of CD59 in PNH and congenital CD59 deficiency is reviewed.

scholarly journals Arrhenius plots of acetylcholinesterase activity in mammalian erythrocytes and in Torpedo electric organ. Effect of solubilization by proteinases and by a phosphatidylinositol-specific phospholipase C

1985 ◽  
Vol 231 (1) ◽  
pp. 237-240 ◽  
Author(s):  
P L Barton ◽  
A H Futerman ◽  
I Silman
Keyword(s):  
Phospholipase C ◽  
Electric Organ ◽  
Acetylcholinesterase Activity ◽  
Arrhenius Plots ◽  
Before And After ◽  
Break Points ◽  
Membrane Bound ◽  
Torpedo Electric Organ ◽  
Erythrocyte Ache ◽  
Lipid Environment

The temperature-dependence of the catalytic activity of acetylcholinesterase (AChE) from rat erythrocyte-ghost membranes and from Torpedo electric-organ membranes was examined. In the case of rat erythrocyte AChE, a non-linear Arrhenius plot was observed both before and after solubilization by a phosphatidylinositol-specific phospholipase C or by proteinase treatment. Similarly, no significant differences were observed in Arrhenius plots of Torpedo electric-organ AChE before or after solubilization. These results support our suggestion that the catalytic subunit of AChE does not penetrate deeply into the lipid bilayer of the plasma membrane and also suggest that care must be taken in ascribing break points in Arrhenius plots of membrane-bound enzymes to changes in their lipid environment.

scholarly journals Adenosine as a metabolic regulator of tissue function: production of adenosine by cytoplasmic 5'-nucleotidases.

2006 ◽  
Vol 53 (2) ◽  
pp. 269-278 ◽  
Author(s):  
Agnieszka Borowiec ◽  
Katarzyna Lechward ◽  
Kinga Tkacz-Stachowska ◽  
Andrzej C Składanowski
Keyword(s):  
Adenosine Receptors ◽  
Purinergic Signaling ◽  
Adenine Nucleotides ◽  
Cell Types ◽  
Nucleoside Transporters ◽  
Signaling System ◽  
Signal Molecule ◽  
Numerous Cell ◽  
Membrane Bound

Adenosine is a product of complete dephosphorylation of adenine nucleotides which takes place in various compartments of the cell. This nucleoside is a significant signal molecule engaged in regulation of physiology and modulation of the function of numerous cell types (i.e. neurons, platelets, neutrophils, mast cells and smooth muscle cells in bronchi and vasculature, myocytes etc.). As part a of purinergic signaling system, adenosine mediates neurotransmission, conduction, secretion, vasodilation, proliferation and cell death. Most of the effects of adenosine help to protect cells and tissues during stress conditions such as ischemia or anoxia. Adenosine receptors and nucleoside transporters are targets for potential drugs in many pathophysiological situations. The adenosine-producing system in vertebrates involves a cascade dephosphorylating ATP and ending with 5'-nucleotidase (EC 3.1.3.5) localized either on the membrane or inside the cell. In this paper the cytoplasmic variants of 5'-nucleotidase are broadly characterized as well as their clinical relevance. The role of AMP-selective 5'-nucleotidase (cN-I) in the heart, skeletal muscle and brain is highlighted. cN-I action is crucial during ischemia and important for the efficacy of some nucleoside-based drugs and in the regulation of the substrate pool for nucleic acids synthesis. Inhibitors used in studying the roles of cytoplasmic and membrane-bound 5'-nucleotidases are also described.

scholarly journals Role of glial filaments in cells and tumors of glial origin: a review

1997 ◽  
Vol 3 (1) ◽  
pp. E2
Author(s):  
James T. Rutka ◽  
Masaji Murakami ◽  
Peter B. Dirks ◽  
Sherri Lynn Hubbard ◽  
Laurence E. Becker ◽  
...  
Keyword(s):  
Transgenic Animals ◽  
Cell Types ◽  
Specific Marker ◽  
Integrin Receptors ◽  
Cellular Space ◽  
Cellular Events ◽  
Supportive Role ◽  
Exact Function ◽  
Capillary Endothelial Cells

In the adult human brain, normal astrocytes constitute nearly 40% of the total central nervous system (CNS) cell population and may assume a star-shaped configuration resembling epithelial cells insofar as the astrocytes remain intimately associated, through their cytoplasmic extensions, with the basement membrane of the capillary endothelial cells and the basal lamina of the glial limitans externa. Although their exact function remains unknown, in the past, astrocytes were thought to subserve an important supportive role for neurons, providing a favorable ionic environment, modulating extracellular levels of neurotransmitters, and serving as spacers that organize neurons. In immunohistochemical preparations, normal, reactive, and neoplastic astrocytes may be positively identified and distinguished from other CNS cell types by the expression of the astrocyte-specific intermediate filament glial fibrillary acidic protein (GFAP). This GFAP is a 50-kD intracytoplasmic filamentous protein that constitutes a portion of, and is specific for, the cytoskeleton of the astrocyte. This protein has proved to be the most specific marker for cells of astrocytic origin under normal and pathological conditions. Interestingly, with increasing astrocytic malignancy, there is progressive loss of GFAP production. As the human gene for GFAP has now been cloned and sequenced, this review begins with a summary of the molecular biology of GFAP including the proven utility of the GFAP promoter in targeting genes of interest to the CNS in transgenic animals. Based on the data provided the authors argue cogently for an expanded role of GFAP in complex cellular events such as cytoskeletal reorganization, maintenance of myelination, cell adhesion, and signaling pathways. As such, GFAP may not represent a mere mechanical integrator of cellular space, as has been previously thought. Rather, GFAP may provide docking sites for important kinases that recognize key cellular substrates that enable GFAP to form a dynamic continuum with microfilaments, integrin receptors, and the extracellular matrix.

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