Probing the extracellular release site of the plasma membrane calcium pump

2000 ◽  
Vol 278 (5) ◽  
pp. C965-C972 ◽  
Author(s):  
Wanyan Xu ◽  
Betty Jo Wilson ◽  
Lin Huang ◽  
Emma L. Parkinson ◽  
Brent J. F. Hill ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Blood Cells ◽  
High Field ◽  
Release Site ◽  
Calcium Pump ◽  
Maximal Inhibition ◽  
Human Red Blood Cells ◽  
Access Channel ◽  
Extracellular Release ◽  
Better Than

The plasma membrane Ca2+ pump is known to mediate Ca2+/H+ exchange. Extracellular protons activated 45Ca2+ efflux from human red blood cells with a half-maximal inhibition constant of 2 nM when the intracellular pH was fixed. An increase in pH from 7.2 to 8.2 decreased the IC50 for extracellular Ca2+ from ∼33 to ∼6 mM. Changing the membrane potential by >54 mV had no effect on the IC50 for extracellular Ca2+. This argues against Ca2+ release through a high-field access channel. Extracellular Ni2+ inhibited Ca2+ efflux with an IC50 of 11 mM. Extracellular Cd2+ inhibited with an IC50 of 1.5 mM, >10 times better than Ca2+. The Cd2+ IC50 also decreased when the pH was raised from 7.1 to 8.2, consistent with Ca2+, Cd2+, and H+ competing for the same site. The higher affinity for inhibition by Ni2+and Cd2+ is consistent with a histidine or cysteine as part of the release site. The cysteine reagent 2-(trimethylammonium)ethyl methanethiosulfonate did not inhibit Ca2+ efflux. Our results are consistent with the notion that the release site contains a histidine.

scholarly journals Localization of calcium in red blood cells.

1983 ◽  
Vol 31 (9) ◽  
pp. 1109-1116 ◽  
Author(s):  
M Borgers ◽  
F J Thone ◽  
B J Xhonneux ◽  
F F De Clerck
Keyword(s):  
Plasma Membrane ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Potassium Phosphate ◽  
Human Red Blood Cells ◽  
A 23187 ◽  
Nonionic Detergent ◽  
Capillary Endothelial Cells ◽  
Membrane Bound ◽  
Triton X

The distribution of calcium is demonstrated in human red blood cells (RBC) with a combined phosphate-pyroantimonate technique (PPA). Freshly collected blood and tissue biopsies were initially fixed in potassium phosphate-glutaraldehyde and the complexed calcium was subsequently visualized on Vibratome sections with potassium pyroantimonate. The majority of cells, both in isolated as well as "in situ" preparations, show a fine granular precipitate located at the inner leaflet of the plasma membrane. A minority of cells lack these membrane-associated deposits, exhibiting instead a random distribution of very fine precipitate in their cytoplasm. Capillary endothelial cells and pericytes are devoid of plasma membrane-bound precipitate. When irreversible crenation of RBC is induced by exposure to ionophore A 23187 and calcium, the sphero-echinocytes loose their membrane-bound precipitate, whereas the cells that retain their discocyte shape demonstrate the usual pattern of membrane-bound deposits. Contrarily, cells showing reversible shape changes induced by either A 23187-Ca2+ challenge, by adenosine triphosphate depletion during aging, or contact with lysolecithin, retain or regain the membrane-bound calcium. This cytochemical demonstrable calcium at the inner leaflet of the plasma membrane is probably bound to acidic phospholipids, since it is readily extractable with the nonionic detergent Triton X-100.

The basal permeability to water of human red blood cells evaluated by a nuclear magnetic resonance technique

1990 ◽  
Vol 10 (1) ◽  
pp. 31-36 ◽  
Author(s):  
Gheorghe Benga ◽  
Victor Ioan Pop ◽  
Octavian Popescu ◽  
Victoria Borza
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Water Diffusion ◽  
Nuclear Magnetic Resonance Technique ◽  
Maximal Inhibition ◽  
Resonance Technique ◽  
Human Red Blood Cells ◽  
Magnetic Resonance Technique

The characteristics of water diffusional permeability (P) of human red blood cells were studied on isolated erythrocytes by a doping nuclear magnetic resonance technique. In order to estimate the basal permeability the maximal inhibition of water diffusion was induced by exposure of red blood cells to p-chloromercuribenzene sulfonate (PCMBS) under various conditions (concentration, duration, temperature). The lowest values of P were around 0.7×10−3 cm s−1 at 10°C, 1.2×10−3 cm s−1 at 15°C, 1.4×10−3 cm s−1 at 20°C, 1.8×10−3 cm s−1 at 25°C, 2.1×10−3 cm s−1 at 30°C and 3.5×10−3 cm s−1 at 37°C. The mean value of the activation energy of water diffusion (Ea,d) was 25 kJ/mol for control and 43.7 kJ/mol for PCMBS-inhibited erythrocytes. The values of P and Ea,d obtained after induction of maximal inhibition of water diffusion by PCMBS can be taken as references for the basal permeability to water of the human red blood cell membrane.

scholarly journals Inhibition of the calcium pump by high cytosolic Ca2+ in intact human red blood cells.

1993 ◽  
Vol 461 (1) ◽  
pp. 63-73 ◽  
Author(s):  
A C Pereira ◽  
D Samellas ◽  
T Tiffert ◽  
V L Lew
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Calcium Pump ◽  
Human Red Blood Cells

scholarly journals Phase separation of the plasma membrane in human red blood cells as a potential tool for diagnosis and progression monitoring of type 1 diabetes mellitus

PLoS ONE ◽  
2017 ◽  
Vol 12 (9) ◽  
pp. e0184109 ◽  
Author(s):  
Giuseppe Maulucci ◽  
Ermanno Cordelli ◽  
Alessandro Rizzi ◽  
Francesca De Leva ◽  
Massimiliano Papi ◽  
...  
Keyword(s):  
Diabetes Mellitus ◽  
Type 1 Diabetes ◽  
Plasma Membrane ◽  
Phase Separation ◽  
Type 1 Diabetes Mellitus ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Human Red Blood Cells ◽  
Potential Tool

scholarly journals Phosphorylation of protein 4.1 in Plasmodium falciparum-infected human red blood cells

Blood ◽  
1994 ◽  
Vol 83 (11) ◽  
pp. 3339-3345 ◽  
Author(s):  
AH Chishti ◽  
GJ Maalouf ◽  
S Marfatia ◽  
J Palek ◽  
W Wang ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Plasma Membrane ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Malaria Parasite ◽  
Malaria Parasites ◽  
Protein 4.1 ◽  
Human Red Blood Cells ◽  
Human Rbcs

The composition of the erythrocyte plasma membrane is extensively modified during the intracellular growth of the malaria parasite Plasmodium falciparum. It has been previously shown that an 80-kD phosphoprotein is associated with the plasma membrane of human red blood cells (RBCs) infected with trophozoite/schizont stage malaria parasites. However, the identity of this 80-kD phosphoprotein is controversial. One line of evidence suggests that this protein is a phosphorylated form of RBC protein 4.1 and that it forms a tight complex with the mature parasite-infected erythrocyte surface antigen. In contrast, evidence from another group indicates that the 80-kD protein is derived from the intracellular malaria parasite. To resolve whether the 80-kD protein is indeed RBC protein 4.1, we made use of RBCs obtained from a patient with homozygous 4.1(-) negative hereditary elliptocytosis. RBCs from this patient are completely devoid of protein 4.1. We report here that this lack of protein 4.1 is correlated with the absence of phosphorylation of the 80-kD protein in parasite- infected RBCs, a finding that provides conclusive evidence that the 80- kD phosphoprotein is indeed protein 4.1. In addition, we also identify and partially characterize a casein kinase that phosphorylates protein 4.1 in P falciparum-infected human RBCs. Based on these results, we suggest that the maturation of malaria parasites in human RBCs is accompanied by the phosphorylation of protein 4.1. This phosphorylation of RBC protein 4.1 may provide a mechanism by which the intracellular malaria parasite alters the mechanical properties of the host plasma membrane and modulates parasite growth and survival in vivo.

scholarly journals Phosphorylation of protein 4.1 in Plasmodium falciparum-infected human red blood cells

Blood ◽  
1994 ◽  
Vol 83 (11) ◽  
pp. 3339-3345 ◽  
Author(s):  
AH Chishti ◽  
GJ Maalouf ◽  
S Marfatia ◽  
J Palek ◽  
W Wang ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Plasma Membrane ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Malaria Parasite ◽  
Malaria Parasites ◽  
Protein 4.1 ◽  
Human Red Blood Cells ◽  
Human Rbcs

Abstract The composition of the erythrocyte plasma membrane is extensively modified during the intracellular growth of the malaria parasite Plasmodium falciparum. It has been previously shown that an 80-kD phosphoprotein is associated with the plasma membrane of human red blood cells (RBCs) infected with trophozoite/schizont stage malaria parasites. However, the identity of this 80-kD phosphoprotein is controversial. One line of evidence suggests that this protein is a phosphorylated form of RBC protein 4.1 and that it forms a tight complex with the mature parasite-infected erythrocyte surface antigen. In contrast, evidence from another group indicates that the 80-kD protein is derived from the intracellular malaria parasite. To resolve whether the 80-kD protein is indeed RBC protein 4.1, we made use of RBCs obtained from a patient with homozygous 4.1(-) negative hereditary elliptocytosis. RBCs from this patient are completely devoid of protein 4.1. We report here that this lack of protein 4.1 is correlated with the absence of phosphorylation of the 80-kD protein in parasite- infected RBCs, a finding that provides conclusive evidence that the 80- kD phosphoprotein is indeed protein 4.1. In addition, we also identify and partially characterize a casein kinase that phosphorylates protein 4.1 in P falciparum-infected human RBCs. Based on these results, we suggest that the maturation of malaria parasites in human RBCs is accompanied by the phosphorylation of protein 4.1. This phosphorylation of RBC protein 4.1 may provide a mechanism by which the intracellular malaria parasite alters the mechanical properties of the host plasma membrane and modulates parasite growth and survival in vivo.

scholarly journals Uptake and metabolism of dipeptides by human red blood cells

1990 ◽  
Vol 271 (1) ◽  
pp. 133-137 ◽  
Author(s):  
H Lochs ◽  
E L Morse ◽  
S A Adibi
Keyword(s):  
Amino Acids ◽  
Plasma Membrane ◽  
Blood Cell ◽  
Red Blood Cells ◽  
Red Blood Cell ◽  
Blood Cells ◽  
Cell Uptake ◽  
Simple Diffusion ◽  
Human Red Blood Cells ◽  
Wide Range

A function of the abundant cytoplasmic peptidases in red blood cells could be hydrolysis of oligopeptides circulating in plasma. To investigate whether human red blood cells actively transport dipeptides for this purpose, these cells were incubated with 14C-labelled glycylproline, glycylsarcosine, glycine, proline and alanine. There was uptake of each dipeptide, as indicated by their recovery as dipeptides in the cell cytoplasm. However, after a brief time (1-2 min) uptake of dipeptides abruptly ceased, while that of amino acids continued. As a result, after 30 min red blood cell uptake of amino acids was 5-13-fold greater than that of any dipeptide. Investigation of intracellular contents after 1 min of incubation revealed different metabolism for different dipeptides. The composition of intracellular radioactivity was 19-71% as intact dipeptides, 0-20% as free amino acids and 8-77% as neither dipeptides nor constituent amino acids. Investigation of the mechanism of dipeptide uptake by red blood cells showed: (1) a lack of hydrolysis by the plasma membrane, (2) no non-specific binding to the plasma membrane, and (3) a lack of saturation over a wide range of concentrations (0.05-50 mM). The data suggest that the mechanism of uptake of trace amounts of dipeptides by human red blood cells is either by simple diffusion or by a carrier system which has a very weak affinity for dipeptides. Upon entry, depending on the molecular structure, dipeptides are either hydrolysed or transformed into new compounds. The red blood cell uptake, however, does not appear to play any appreciable role in clearance of dipeptides from the plasma in the human.

Distribution of plasma membrane Ca2+ pump activity in normal human red blood cells

Blood ◽  
2003 ◽  
Vol 102 (12) ◽  
pp. 4206-4213 ◽  
Author(s):  
Virgilio L. Lew ◽  
Nuala Daw ◽  
Deisy Perdomo ◽  
Zipora Etzion ◽  
Robert M. Bookchin ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Mean Value ◽  
Mean Values ◽  
Human Red Blood Cells ◽  
Cell Age ◽  
Normal Human ◽  
Osmotic Lysis ◽  
Pathologic Processes

Abstract The plasma membrane calcium pump (PMCA) is the only active Ca2+ transporter in human red blood cells (RBCs). Previous measurements of maximal Ca2+ extrusion rates (Vmax) reported only mean values in the RBC population. Despite early evidence for differences in Ca2+ extrusion capacity among RBCs, the precise Vmax distribution remained unknown. It was important to characterize this distribution to assess the range and modality (uni- or multimodal) of PMCA Vmax variation and the likelihood of RBCs with elevated [Ca2+]i in the circulation participating in physiologic and pathologic processes. We report here the application of a new method to investigate the detailed distribution of PMCA Vmax activity in RBCs. The migrating profile of osmotic lysis curves was used to identify and quantify the fraction of cells that extrude a uniform Ca2+ load at different rates. The results revealed that RBCs from single donors have large variations in PMCA activity that follow a unimodal, broad distribution pattern consistently skewed toward higher Vmax values, suggesting an excess of cells with Vmax higher than the mean value. The method applied may provide a way of evaluating whether the observed variation in PMCA Vmax is related to cell age. (Blood. 2003;102:4206-4213)

Sign in / Sign up

Export Citation Format

Share Document