scholarly journals Levels of Human Erythrocyte Membrane-Bound and Cytosolic Glycohydrolases Are Associated with Oxidative Stress in Erectile Dysfunction Patients

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
L. Massaccesi ◽  
G. V. Melzi d’Eril ◽  
G. M. Colpi ◽  
G. Tettamanti ◽  
G. Goi ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Plasma Membrane ◽  
Erectile Dysfunction ◽  
Plasma Membranes ◽  
Lag Time ◽  
Specific Marker ◽  
Human Erythrocyte Membrane ◽  
Key Enzyme ◽  
Membrane Bound

Oxidative stress (OS) and production of NO, by endothelium nitric oxide synthetase (eNOS), are involved in the pathophysiology of erectile dysfunction (ED). Moreover, OS induces modifications of the physicochemical properties of erythrocyte (RBC) plasma membranes and of the enzyme content of the same membranes. Due to their role in signalling early membrane alterations in OS-related pathologies, several plasma membrane and cytosolic glycohydrolases of human RBC have been proposed as new markers of cellular OS. In RBC, NOS can be activated and deactivated by phosphorylation/glycosylation. In this regulatory mechanism O-β-N-AcetylGlucosaminidase is a key enzyme. Cellular levels of O-GlcNAcylated proteins are related to OS; consequently dysfunctional eNOS O-GlcNAcylation seems to have a crucial role in ED. To elucidate the possible association between RBC glycohydrolases and OS, plasma hydroperoxides and antioxidant total defenses (Lag-time), cytosolic O-β-N-AcetylGlucosaminidase, cytosolic and membrane Hexosaminidase, membraneβ-D-Glucuronidase, andα-D-Glucosidase have been studied in 39 ED patients and 30 controls. In ED subjects hydroperoxides and plasma membrane glycohydrolases activities are significantly increased whereas Lag-time values and cytosolic glycohydrolases activities are significantly decreased. These data confirm the strong OS status in ED patients, the role of the studied glycohydrolases as early OS biomarker and suggest their possible use as specific marker of ED patients, particularly in those undergoing nutritional/pharmacological antioxidant therapy.

scholarly journals Role of plasma-membrane-bound sialidase NEU3 in clathrin-mediated endocytosis

2015 ◽  
Vol 470 (1) ◽  
pp. 131-144 ◽  
Author(s):  
Macarena Rodriguez-Walker ◽  
Aldo A. Vilcaes ◽  
Eduardo Garbarino-Pico ◽  
José L. Daniotti
Keyword(s):  
Plasma Membrane ◽  
Subcellular Distribution ◽  
Cellular Functions ◽  
Coated Pits ◽  
Key Enzyme ◽  
Membrane Bound

Sialidase NEU3 is a key enzyme in the catabolism of gangliosides. We demonstrated that NEU3 impairs cargo internalization via clathrin-coated pits, affecting AP-2 subcellular distribution. This study delineates previously unidentified cellular functions of NEU3.

Spreading of a sperm surface antigen within the plasma membrane of the egg after fertilization in the rat

Development ◽  
1983 ◽  
Vol 75 (1) ◽  
pp. 259-270
Author(s):  
Stephen J. Gaunt
Keyword(s):  
Monoclonal Antibody ◽  
Plasma Membrane ◽  
Guinea Pig ◽  
Surface Antigen ◽  
Plasma Membranes ◽  
Entire Surface ◽  
Sperm Tail ◽  
Sperm Surface ◽  
Sperm Antigens

The rat sperm surface antigen 2D6, located over the entire surface of the spermatozoon, is shown by use of a monoclonal antibody in indirect immunofluorescence experiments to spread laterally over the surface of the egg after fusion of sperm and egg plasma membranes at fertilization. Freshly fertilized eggs, obtained from superovulated rats 14h after hCG injection, showed the 2D6 antigen to have spread in a gradient over a discrete fan-shaped area of the egg surface anterior to the protruding sperm tail. Eggs at a later stage of sperm incorporation, obtained 20 h after hCG injection, snowed that the spread of antigen had extended to cover most or all of their surfaces. By 40 h after hCG injection, the approximate time that fertilized eggs cleaved to form 2-cell embryos, most of the 2D6 antigen had been lost from the cell surface. Fertilized eggs, but not unfertilized eggs or 2-cell embryos, were lysed by 2D6 monoclonal antibody in the presence of guinea pig complement. A model for sperm-egg fusion is presented to account for the observed pattern of spreading shown by the 2D6 antigen. The possible role of sperm antigens on the egg surface is discussed.

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 5′-Nucleotidases of chicken gizzard and human pancreatic adenocarcinoma cells are anchored to the plasma membrane via a phosphatidylinositol–glycan

1989 ◽  
Vol 262 (1) ◽  
pp. 33-40 ◽  
Author(s):  
U Stochaj ◽  
K Flocke ◽  
W Mathes ◽  
H G Mannherz
Keyword(s):  
Plasma Membrane ◽  
Pancreatic Adenocarcinoma ◽  
Plasma Membranes ◽  
Chicken Gizzard ◽  
Human Pancreatic Adenocarcinoma ◽  
Adenocarcinoma Cells ◽  
Increased Sensitivity ◽  
Membrane Bound ◽  
Membrane Anchoring ◽  
Pancreatic Adenocarcinoma Cell Line

We have analysed the membrane anchorage of plasma-membrane 5′-nucleotidase, an ectoenzyme which can mediate binding to components of the extracellular matrix. We demonstrated that the purified enzyme obtained from chicken gizzard and a human pancreatic adenocarcinoma cell line were both completely transformed into a hydrophilic form by treatment with phospholipases C and D, cleaving glycosylphosphatidylinositol (GPI). These data indicate the presence of a glycolipid linker employed for membrane anchoring of the 5′-nucleotidase obtained from both sources. Incubation of plasma membranes under identical conditions revealed that about half of the AMPase activity was resistant to GPI-hydrolysing phospholipases. Investigation of the enzymic properties of purified chicken gizzard 5′-nucleotidase revealed only minor changes after removal of the phosphatidylinositol linker. However, cleavage of the membrane anchor resulted in an increased sensitivity towards inhibition by concanavalin A. After tissue fractionation, chicken gizzard 5′-nucleotidase could be obtained as either a membrane-bound or a soluble protein; the latter is suspected to be released from the plasma membrane by endogenous phospholipases. Higher-molecular-mass proteins immuno-cross-reactive with the purified chicken gizzard 5′-nucleotidase were detected as both soluble and membrane-bound forms.

scholarly journals ROLE OF THE GAMETE MEMBRANES IN FERTILIZATION IN SACCOGLOSSUS KOWALEVSKII (ENTEROPNEUSTA)

1963 ◽  
Vol 19 (3) ◽  
pp. 501-518 ◽  
Author(s):  
Laura Hunter Colwin ◽  
Arthur L. Colwin
Keyword(s):  
Plasma Membrane ◽  
Membrane Fusion ◽  
Plasma Membranes ◽  
Sperm Nucleus ◽  
Zygote Formation ◽  
General Hypothesis ◽  
Acrosomal Vesicle ◽  
Saccoglossus Kowalevskii ◽  
Sperm Plasma Membrane

An earlier paper showed that in Saccoglossus the acrosomal tubule makes contact with the egg plasma membrane. The present paper includes evidence that the sperm and egg plasma membranes fuse to establish the single continuous zygote membrane which, consequently, is a mosaic. Contrary to the general hypothesis of Tyler, pinocytosis or phagocytosis plays no role in zygote formation. Contact between the gametes is actually between two newly exposed surfaces: in the spermatozoon, the surface was formerly the interior of the acrosomal vesicle; in the egg, it was membrane previously covered by the egg envelopes. The concept that all the events of fertilization are mediated by a fertilizin-antifertilizin reaction seems an oversimplification of events actually observed: rather, the evidence indicates that a series of specific biochemical interactions probably would be involved. Gamete membrane fusion permits sperm periacrosomal material to meet the egg cytoplasm; if an activating substance exists in the spermatozoon it probably is periacrosomal rather than acrosomal in origin. The contents of the acrosome are expended in the process of delivering the sperm plasma membrane to the egg plasma membrane. After these membranes coalesce, the sperm nucleus and other internal sperm structures move into the egg cytoplasm.

scholarly journals Plasma membrane association of Acanthamoeba myosin I.

1989 ◽  
Vol 109 (4) ◽  
pp. 1519-1528 ◽  
Author(s):  
H Miyata ◽  
B Bowers ◽  
E D Korn
Keyword(s):  
Plasma Membrane ◽  
Binding Site ◽  
Heavy Chain ◽  
Membrane Fraction ◽  
Plasma Membranes ◽  
Actin Binding ◽  
Plasma Membrane Fraction ◽  
Myosin I ◽  
Membrane Bound ◽  
Actin Binding Site

Myosin I accounted for approximately 2% of the protein of highly purified plasma membranes, which represents about a tenfold enrichment over its concentration in the total cell homogenate. This localization is consistent with immunofluorescence analysis of cells that shows myosin I at or near the plasma membrane as well as diffusely distributed in the cytoplasm with no apparent association with cytoplasmic organelles or vesicles identifiable at the level of light microscopy. Myosin II was not detected in the purified plasma membrane fraction. Although actin was present in about a tenfold molar excess relative to myosin I, several lines of evidence suggest that the principal linkage of myosin I with the plasma membrane is not through F-actin: (a) KI extracted much more actin than myosin I from the plasma membrane fraction; (b) higher ionic strength was required to solubilize the membrane-bound myosin I than to dissociate a complex of purified myosin I and F-actin; and (c) added purified myosin I bound to KI-extracted plasma membranes in a saturable manner with maximum binding four- to fivefold greater than the actin content and with much greater affinity than for pure F-actin (apparent KD of 30-50 nM vs. 10-40 microM in 0.1 M KCl plus 2 mM MgATP). Thus, neither the MgATP-sensitive actin-binding site in the NH2-terminal end of the myosin I heavy chain nor the MgATP-insensitive actin-binding site in the COOH-terminal end of the heavy chain appeared to be the principal mechanism of binding of myosin I to plasma membranes through F-actin. Furthermore, the MgATP-sensitive actin-binding site of membrane-bound myosin I was still available to bind added F-actin. However, the MgATP-insensitive actin-binding site appeared to be unable to bind added F-actin, suggesting that the membrane-binding site is near enough to this site to block sterically its interaction with actin.

Processing of receptor-bound somatostatin: internalization and degradation by pancreatic acini

1987 ◽  
Vol 252 (4) ◽  
pp. G535-G542 ◽  
Author(s):  
N. Viguerie ◽  
J. P. Esteve ◽  
C. Susini ◽  
N. Vaysse ◽  
A. Ribet
Keyword(s):  
Plasma Membrane ◽  
Plasma Membranes ◽  
Specific Binding ◽  
Specific Radioactivity ◽  
Pancreatic Acinar Cells ◽  
Nuclear Fraction ◽  
Pancreatic Acini ◽  
Specific Binding Sites ◽  
Membrane Bound ◽  
Membrane Level

We have previously demonstrated the presence of specific binding sites for somatostatin on plasma membranes from pancreatic acinar cells. In the present study we attempted to characterize the fate of receptor-bound 125I-[Tyr11]somatostatin. Internalization of somatostatin was rapid (reaching a plateau at 20% of the cell-associated specific radioactivity) and temperature dependent. To follow the processing of bound somatostatin, acini were incubated with 125I-[Tyr11]somatostatin at 5 degrees C during 16 h then, after washing, incubated at 37 degrees C for 90 min in fresh medium. Surface-bound somatostatin decreased rapidly, whereas radioactivity increased in the cell interior and the incubation medium. Intracellular and membrane-bound radioactivity was mainly intact 125I-[Tyr11]somatostatin. Degradation occurred at the plasma membrane level and led to iodotyrosine production. After 15 min of incubation, 15% of the initially surface-bound 125I-[Tyr11]somatostatin was compartmentalized within the cell, mainly in the microsomal fraction. After 30 min, a significant increase in radioactivity appeared in the nuclear fraction. These results indicate that the major part of somatostatin cellular degradation takes place at the plasma membrane level. Within the cell, somatostatin is routed to the nucleus via particular fractions sedimenting with microsomal vesicles.

scholarly journals Manganese Induces Oxidative Stress, Redox State Unbalance and Disrupts Membrane Bound ATPases on Murine Neuroblastoma Cells In Vitro: Protective Role of Silymarin

2011 ◽  
Vol 36 (8) ◽  
pp. 1546-1557 ◽  
Author(s):  
Yassine Chtourou ◽  
Khaled Trabelsi ◽  
Hamadi Fetoui ◽  
Ghada Mkannez ◽  
Héla Kallel ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Redox State ◽  
Neuroblastoma Cells ◽  
Protective Role ◽  
Murine Neuroblastoma ◽  
Membrane Bound

Outside or inside: role of the subcellular localization of DP4-like enzymes for substrate conversion and inhibitor effects

2011 ◽  
Vol 392 (3) ◽  
Author(s):  
Ute Bank ◽  
Anke Heimburg ◽  
Astrid Wohlfarth ◽  
Gudrun Koch ◽  
Karsten Nordhoff ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Low Molecular Weight ◽  
Immune Functions ◽  
Cellular Functions ◽  
Fluorogenic Substrates ◽  
Cellular Effects ◽  
Viable Cells ◽  
Substrate Conversion ◽  
Membrane Bound

Abstract The discovery of the DP4-related enzymes DP8 and DP9 raised controversial discussion regarding the physiological and pathophysiological function of distinct members of the DP4 family. Particularly with regard to their potential relevance in regulating immune functions, it is of interest to know which role the subcellular distribution of the enzymes play. Synthetic substrates as well as low molecular weight inhibitors are widely used as tools, but little is yet known regarding their features in cell experiments, such as their plasma membrane penetration capacity. The fluorogenic substrates Gly-Pro-AMC or (Ala-Pro)2-R110 predominantly detect plasma membrane-bound activities of viable cells (less than 0.1% of fluorochromes R110 or AMC inside viable cells after 1 h incubation). Additionally, the selective and non-selective DP8/9 inhibitors allo-Ile-isoindoline and Lys[Z(NO2)]-pyrrolidide were found to be incapable of passing the plasma membrane easily. This suggests that previously reported cellular effects are not due to inhibition of the cytosolic enzymes DP8 or DP9. Moreover, our enzymatic studies with viable cells provided evidence that DP8 and/or DP9 are also present on the surface of immune cells under certain circumstances and could gain relevance particularly in the absence of DP4 expression. In summary, in cells which do express DP4 on the surface, this archetypical member of the DP4 family is the most relevant peptidase in the regulation of cellular functions.

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