Effect of liver plasma membranes on G-actin. II. Fate of actin-bound nucleotide

1983 ◽  
Vol 61 (2-3) ◽  
pp. 93-98 ◽  
Author(s):  
Helene-Marie Thérien ◽  
Julian Gruda
Keyword(s):  
Plasma Membranes ◽  
Protective Action ◽  
Liver Plasma Membranes ◽  
Free Nucleotides ◽  
Rapid Destruction ◽  
Liver Fraction ◽  
Denaturation Process

G-actin incubated in presence of a liver fraction enriched in plasma membranes rapidly denatures, as evidenced by the biphasic loss of polymerizability and DNase inhibition. The inactivation is shown to result from the loss of actin-bound nucleotide induced by the rapid destruction of free nucleotides by membrane NPases. This is further supported by the observation that addition of either ATP or ADP to actin that has been exposed to membranes completely stops the denaturation process and partly restores polymerizing capacity. The biphasic aspect of inactivation is explained by the protective action of AMP and (or) adenosine formed in the course of the incubation.

Effect of liver plasma membranes on G-actin. I. Possible implication of membrane NPases in inactivation of G-actin

1983 ◽  
Vol 61 (2-3) ◽  
pp. 85-92 ◽  
Author(s):  
Julian Gruda ◽  
Jean-Marc Pollender ◽  
Helene-Marie Therien
Keyword(s):  
Incubation Medium ◽  
Plasma Membranes ◽  
Liver Plasma Membranes ◽  
Inactivation Process ◽  
Liver Fraction

G-actin incubated in the presence of a liver fraction enriched in plasma membranes is rapidly inactivated, as indicated by the biphasic loss of polymerizability and DNase inhibition. The rates of inactivation as measured by viscosity are greatly influenced by temperature, but almost independent of membrane concentrations at least in the low range of concentrations tested (< 250 μg protein/mL). The loss of DNase inhibition capacity proceeds at rates two to three times slower than the loss of polimerizability. The inactivation of actin in the presence of membranes cannot be attributed to proteolysis nor to a phosphorylation of actin by membranes. However, it is shown that in the course of the incubation, medium ATP is rapidly converted into AMP and adenosine and that the destruction of ATP is almost complete at the start of the inactivation process. A mechanism is presented relating the destruction of ATP to actin inactivation.

scholarly journals Tauroursodeoxycholic Acid (TUDCA)—Lipid Interactions and Antioxidant Properties of TUDCA Studied in Model of Photoreceptor Membranes

Membranes ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 327
Author(s):  
Michał J. Sabat ◽  
Anna M. Wiśniewska-Becker ◽  
Michał Markiewicz ◽  
Katarzyna M. Marzec ◽  
Jakub Dybas ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Plasma Membranes ◽  
Electron Paramagnetic Resonance Spectroscopy ◽  
Protective Action ◽  
Antioxidant Properties ◽  
Model Membranes ◽  
Dynamics Simulation ◽  
Resonance Spectroscopy ◽  
Paramagnetic Resonance ◽  
Tauroursodeoxycholic Acid

Tauroursodeoxycholic acid (TUDCA), a hydrophilic bile acid containing taurine conjugated with the ursodeoxycholic acid (UDCA), has been known and used from ancient times as a therapeutic compound in traditional Chinese medicine. TUDCA has recently been gaining significant interest as a neuroprotective agent, also exploited in the visual disorders. Among several mechanisms of TUDCA’s protective action, its antioxidant activity and stabilizing effect on mitochondrial and plasma membranes are considered. In this work we investigated antioxidant activity of TUDCA and its impact on structural properties of model membranes of different composition using electron paramagnetic resonance spectroscopy and the spin labeling technique. Localization of TUDCA molecules in a pure POPC bilayer has been studied using a molecular dynamics simulation (MD). The obtained results indicate that TUDCA is not an efficient singlet oxygen (1O2 (1Δg)) quencher, and the determined rate constant of its interaction with 1O2 (1Δg) is only 1.9 × 105 M−1s−1. However, in lipid oxidation process induced by a Fenton reaction, TUDCA reveals substantial antioxidant activity significantly decreasing the rate of oxygen consumption in the system studied. In addition, TUDCA induces slight, but noticeable changes in the polarity and fluidity of the investigated model membranes. The results of performed MD simulation correspond very well with the experimental results.

scholarly journals Gs mediates hormonal inhibition of the calcium pump in liver plasma membranes.

1993 ◽  
Vol 268 (4) ◽  
pp. 2368-2372
Author(s):  
C. Jouneaux ◽  
Y. Audigier ◽  
P. Goldsmith ◽  
F. Pecker ◽  
S. Lotersztajn
Keyword(s):  
Plasma Membranes ◽  
Calcium Pump ◽  
Liver Plasma Membranes

scholarly journals Quantitative Aspects of the Insulin-Receptor Interaction in Liver Plasma Membranes

1974 ◽  
Vol 249 (7) ◽  
pp. 2249-2257 ◽  
Author(s):  
C. Ronald Kahn ◽  
Pierre Freychet ◽  
Jesse Roth ◽  
David M. Neville
Keyword(s):  
Insulin Receptor ◽  
Plasma Membranes ◽  
Receptor Interaction ◽  
Liver Plasma Membranes

scholarly journals The NSILA-s receptor in liver plasma membranes. Characterization and comparison with the insulin receptor

1975 ◽  
Vol 250 (23) ◽  
pp. 8990-8996 ◽  
Author(s):  
K Megyesi ◽  
CR Kahn ◽  
J Roth ◽  
DM Neville ◽  
SP Nissley ◽  
...  
Keyword(s):  
Insulin Receptor ◽  
Plasma Membranes ◽  
Liver Plasma Membranes

scholarly journals Lysophosphatidylcholines can modulate the activity of the glucagon-stimulated adenylate cyclase from rat liver plasma membranes

1979 ◽  
Vol 178 (1) ◽  
pp. 217-221 ◽  
Author(s):  
M D Houslay ◽  
R W Palmer
Keyword(s):  
Adenylate Cyclase ◽  
Rat Liver ◽  
Plasma Membranes ◽  
Hormone Receptors ◽  
Cyclase Activity ◽  
Adenylate Cyclase Activity ◽  
Liver Plasma Membranes ◽  
Rat Liver Plasma Membranes ◽  
Increased Sensitivity

1. Synthetic lysophosphatidylcholines inhibit the glucagon-stimulated adenylate cyclase activity of rat liver plasma membranes at concentrations two to five times lower than those needed to inhibit the fluoride-stimulated activity. 2. Specific 125I-labelled glucagon binding to hormone receptors is inhibited at concentrations similar to those inhibiting the fluoride-stimulated activity. 3. At concentrations of lysophosphatidylcholines immediately below those causing inhibition, an activation of adenylate cyclase activity or hormone binding was observed. 4 These effects are essentially reversible. 5. We conclude that the increased sensitivity of glucagon-stimulated adenylate cyclase to inhibition may be due to the lysophosphatidylcholines interfering with the physical coupling between the hormone receptor and catalytic unit of adenylate cyclase. 6. We suggest that, in vivo, it is possible that lysophosphatidylcholines may modulate the activity of adenylate cyclase only when it is in the hormone-stimulated state.

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