scholarly journals Alteration of membrane phospholipid bilayer organization in human erythrocytes during drug-induced endocytosis.

1983 ◽  
Vol 72 (5) ◽  
pp. 1698-1705 ◽  
Author(s):  
S L Schrier ◽  
D T Chiu ◽  
M Yee ◽  
K Sizer ◽  
B Lubin
Keyword(s):  
Human Erythrocytes ◽  
Phospholipid Bilayer ◽  
Membrane Phospholipid ◽  
Drug Induced

Oxidative Damage Does Not Alter Membrane Phospholipid Asymmetry in Human Erythrocytes†

Biochemistry ◽  
1997 ◽  
Vol 36 (22) ◽  
pp. 6768-6776 ◽  
Author(s):  
Kitty de Jong ◽  
Danielle Geldwerth ◽  
Frans A. Kuypers
Keyword(s):  
Oxidative Damage ◽  
Human Erythrocytes ◽  
Membrane Phospholipid ◽  
Phospholipid Asymmetry

Membrane phospholipid organization in calcium-loaded human erythrocytes

1987 ◽  
Vol 902 (2) ◽  
pp. 253-262 ◽  
Author(s):  
R. Chandra ◽  
P.C. Joshi ◽  
V.K. Bajpai ◽  
C.M. Gupta
Keyword(s):  
Human Erythrocytes ◽  
Membrane Phospholipid

scholarly journals ATP-dependent interaction of propranolol and local anaesthetic with sarcoplasmic reticulum. Stimulation of Ca2+ efflux

1988 ◽  
Vol 256 (3) ◽  
pp. 733-739 ◽  
Author(s):  
V Shoshan-Barmatz
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Atpase Activity ◽  
Local Anaesthetics ◽  
Inhibitory Effect ◽  
Phospholipid Bilayer ◽  
Drug Induced ◽  
Protein Factor ◽  
Dependent Inhibition ◽  
Drug Modification ◽  
Stimulation Of

Preincubation of sarcoplasmic reticulum (SR) with propranolol or tetracaine inhibits Ca2+ accumulation and stimulates ATPase activity by more than 2-fold. This effect is obtained only when the preincubation is carried out in the presence of ATP or other nucleoside triphosphates. The (ATP + drug)-induced inhibition of Ca2+ accumulation is pH-dependent, increasing as the pH rises above 7.5. The presence of micromolar concentrations of Ca2+ or Mg2+ during the preincubation prevents the inhibitory effect of ATP plus drug on Ca2+ accumulation or ATPase activity. The (ATP + drug) modification of SR vesicles resulted in stimulation of a rapid Ca2+ efflux from passively loaded vesicles. The ATP-dependent inhibition of Ca2+ accumulation by the drug is obtained with other local anaesthetics. The drug concentration required for 50% inhibition was 0.15 mM for dibucaine and 0.4 mM for both propranolol and tetracaine, whereas it was 5 mM, 8 mM and greater than 10 mM for lidocaine, benzocaine and procaine respectively. The heavy SR vesicles were only slightly affected by the incubation with propranolol or tetracaine in the presence of ATP, but their sensitivity increased markedly after storage at 0 degrees C for 24-48 h. These results suggest that propranolol and some local anaesthetics, in the presence of ATP, stimulate Ca2+ efflux by modifying a protein factor(s) rather than the phospholipid bilayer.

scholarly journals Calcium distribution within human erythrocytes during endocytosis

Blood ◽  
1980 ◽  
Vol 56 (4) ◽  
pp. 677-682
Author(s):  
SL Schrier ◽  
M Johnson ◽  
I Junga ◽  
J Krueger
Keyword(s):  
Adenosine Triphosphate ◽  
Deleterious Effect ◽  
Human Erythrocytes ◽  
Drug Induced ◽  
Calcium Distribution

In order to study 45Ca movements within erythrocytes, a method was devised that had minimal deleterious effect on the treated erythrocytes. Agents that induce endocytosis in intact erythrocytes (primaquine, vinblastine, and chlorpromazine) caused a prompt movement of 45Ca from cytosol to membrane-associated sites. This drug-induced movement of 45Ca to membrane sites was blocked by depleting erythrocytes of adenosine triphosphate (ATP) or by incubating them with known inhibitors of endocytosis, NaF of N-ethylmaleimide (NEM). It appears that endocytosis in intact human erythrocytes involves the movement and redistribution of 45Ca from cytosol to membrane-associated sites. Therefore, in the erythrocyte, as in perhaps other cells, movement of Ca from one site to another may modulate important cellular biologic functions.

Effects of N-phosphorylated amino acids on membrane phospholipid of human erythrocytes

1993 ◽  
Vol 19 (2) ◽  
pp. 85-94 ◽  
Author(s):  
Yanmei Li ◽  
Xiuhong Wang ◽  
Yufen Zhao ◽  
Jianyuan Yu ◽  
Mingqiu Wan ◽  
...  
Keyword(s):  
Amino Acids ◽  
Human Erythrocytes ◽  
Membrane Phospholipid

scholarly journals Yeast phosphatidic acid phosphatase Pah1 hops and scoots along the membrane phospholipid bilayer

2020 ◽  
Vol 61 (8) ◽  
pp. 1232-1243 ◽  
Author(s):  
Joanna M. Kwiatek ◽  
George M. Carman
Keyword(s):  
Phosphatase Activity ◽  
Membrane Surface ◽  
Phospholipid Composition ◽  
Phospholipid Bilayer ◽  
Membrane Phospholipid ◽  
Membrane Phospholipids ◽  
Fatty Acyl Moiety ◽  
Triacylglycerol Synthesis ◽  
Er Membrane

PA phosphatase, encoded by PAH1 in the yeast Saccharomyces cerevisiae, catalyzes the Mg2+-dependent dephosphorylation of PA, producing DAG at the nuclear/ER membrane. This enzyme plays a major role in triacylglycerol synthesis and in the regulation of phospholipid synthesis. As an interfacial enzyme, PA phosphatase interacts with the membrane surface, binds its substrate, and catalyzes its reaction. The Triton X-100/PA-mixed micellar system has been utilized to examine the activity and regulation of yeast PA phosphatase. This system, however, does not resemble the in vivo environment of the membrane phospholipid bilayer. We developed an assay system that mimics the nuclear/ER membrane to assess PA phosphatase activity. PA was incorporated into unilamellar phospholipid vesicles (liposomes) composed of the major nuclear/ER membrane phospholipids, PC, PE, PI, and PS. We optimized this system to support enzyme-liposome interactions and to afford activity that is greater than that obtained with the aforementioned detergent system. Activity was regulated by phospholipid composition, whereas the enzyme’s interaction with liposomes was insensitive to composition. Greater activity was attained with large (≥100 nm) versus small (50 nm) vesicles. The fatty-acyl moiety of PA had no effect on this activity. PA phosphatase activity was dependent on the bulk (hopping mode) and surface (scooting mode) concentrations of PA, suggesting a mechanism by which the enzyme operates along the nuclear/ER membrane in vivo.

scholarly journals Calcium distribution within human erythrocytes during endocytosis

Blood ◽  
1980 ◽  
Vol 56 (4) ◽  
pp. 677-682 ◽  
Author(s):  
SL Schrier ◽  
M Johnson ◽  
I Junga ◽  
J Krueger
Keyword(s):  
Adenosine Triphosphate ◽  
Deleterious Effect ◽  
Human Erythrocytes ◽  
Drug Induced ◽  
Calcium Distribution

Abstract In order to study 45Ca movements within erythrocytes, a method was devised that had minimal deleterious effect on the treated erythrocytes. Agents that induce endocytosis in intact erythrocytes (primaquine, vinblastine, and chlorpromazine) caused a prompt movement of 45Ca from cytosol to membrane-associated sites. This drug-induced movement of 45Ca to membrane sites was blocked by depleting erythrocytes of adenosine triphosphate (ATP) or by incubating them with known inhibitors of endocytosis, NaF of N-ethylmaleimide (NEM). It appears that endocytosis in intact human erythrocytes involves the movement and redistribution of 45Ca from cytosol to membrane-associated sites. Therefore, in the erythrocyte, as in perhaps other cells, movement of Ca from one site to another may modulate important cellular biologic functions.

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