Insulin effect in vitro on human erythrocyte plasma membrane

1981 ◽  
Vol 37 (4) ◽  
pp. 431-433 ◽  
Author(s):  
P. Luly ◽  
P. Baldini ◽  
S. Incerpi ◽  
E. Tria
Keyword(s):  
Plasma Membrane ◽  
Human Erythrocyte ◽  
Insulin Effect ◽  
Erythrocyte Plasma Membrane

scholarly journals Purification of the NF2 Tumor Suppressor Protein from Human Erythrocytes

2006 ◽  
Vol 33 (4) ◽  
pp. 394-402 ◽  
Author(s):  
Hitesh K. Jindal ◽  
Kazumi Yoshinaga ◽  
Pil-Soo Seo ◽  
Mohini Lutchman ◽  
Patrick A. Dion ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Tumor Suppressor ◽  
Erythrocyte Membrane ◽  
Human Erythrocyte ◽  
Mammalian Cells ◽  
Tumor Suppressor Protein ◽  
Human Erythrocyte Membrane ◽  
Protein 4.1 ◽  
Erythrocyte Plasma Membrane ◽  
Inside Out

Background:Neurofibromatosis type 2 (NF2) is an autosomal dominant disease predisposing individuals to the risk of developing tumors of cranial and spinal nerves. The NF2 tumor suppressor protein, known as Merlin/Schwanomin, is a member of the protein 4.1 superfamily that function as links between the cytoskeleton and the plasma membrane.Methods:Upon selective extraction of membrane-associated proteins from erythrocyte plasma membrane (ghosts) using low ionic strength solution, the bulk of NF2 protein remains associated with the spectrin-actin depleted inside-out-vesicles. Western blot analysis showed a ~70 kDa polypeptide in the erythrocyte plasma membrane. Furthermore, quantitative removal of NF2 protein from the inside-out-vesicles was achieved using 1.0 M potassium iodide, a treatment known to remove tightly-bound peripheral membrane proteins.Results:These results suggest a novel mode of NF2 protein association with the erythrocyte membrane that is distinct from the known membrane interactions of protein 4.1. Based on these biochemical properties, several purification strategies were devised to isolate native NF2 protein from human erythrocyte ghosts. Using purified and recombinant NF2 protein as internal standards, we quantified approximately ~41-65,000 molecules of NF2 protein per erythrocyte.Conclusion:We provide evidence for the presence of NF2 protein in the human erythrocyte membrane. The identification of NF2 protein in the human erythrocyte membrane will make it feasible to discover novel interactions of NF2 protein utilizing powerful techniques of erythrocyte biochemistry and genetics in mammalian cells.

scholarly journals Electron Pathways through Erythrocyte Plasma Membrane in Human Physiology and Pathology: Potential Redox Biomarker?

2007 ◽  
Vol 2 ◽  
pp. 117727190700200 ◽  
Author(s):  
Elena Matteucci ◽  
Ottavio Giampietro
Keyword(s):  
Plasma Membrane ◽  
Human Erythrocyte ◽  
Functional Organization ◽  
Redox Homeostasis ◽  
The Body ◽  
Influential Factor ◽  
Transport Systems ◽  
Disease States ◽  
Erythrocyte Plasma Membrane

Erythrocytes are involved in the transport of oxygen and carbon dioxide in the body. Since pH is the influential factor in the Bohr-Haldane effect, pHi is actively maintained via secondary active transports Na+/H+ exchange and HC3–/Cl– anion exchanger. Because of the redox properties of the iron, hemoglobin generates reactive oxygen species and thus, the human erythrocyte is constantly exposed to oxidative damage. Although the adult erythrocyte lacks protein synthesis and cannot restore damaged proteins, it is equipped with high activity of protective enzymes. Redox changes in the cell initiate various signalling pathways. Plasma membrane oxido-reductases (PMORs) are trans-membrane electron transport systems that have been found in the membranes of all cells and have been extensively characterized in the human erythrocyte. Erythrocyte PMORs transfer reducing equivalents from intracellular reductants to extracellular oxidants, thus their most important role seems to be to enable the cell respond to changes in intra- and extra-cellular redox environments. So far the activity of erythrocyte PMORs in disease states has not been systematically investigated. This review summarizes present knowledge on erythrocyte electron transfer activity in humans (health, type 1 diabetes, diabetic nephropathy, and chronic uremia) and hypothesizes an integrated model of the functional organization of erythrocyte plasma membrane where electron pathways work in parallel with transport metabolons to maintain redox homeostasis.

scholarly journals Multiple metabolic pools of phosphoinositides and phosphatidate in human erythrocytes incubated in a medium that permits rapid transmembrane exchange of phosphate

1987 ◽  
Vol 244 (1) ◽  
pp. 209-217 ◽  
Author(s):  
C E King ◽  
L R Stephens ◽  
P T Hawkins ◽  
G R Guy ◽  
R H Michell
Keyword(s):  
Plasma Membrane ◽  
Human Erythrocyte ◽  
Plasma Membranes ◽  
Age Distribution ◽  
Specific Radioactivity ◽  
Human Erythrocytes ◽  
Metabolic Compartmentation ◽  
To Come ◽  
Metabolic Heterogeneity

1. A Hepes-based medium has been devised which allows rapid Pi exchange across the plasma membrane of the human erythrocyte. This allows the metabolically labile phosphate pools of human erythrocytes to come to equilibrium with [32P]Pi in the medium after only 5 h in vitro. 2. After 5-7 h incubation with [32P]Pi in this medium, only three phospholipids, phosphatidic acid (PtdOH), phosphatidylinositol 4-phosphate (PtdIns4P) and phosphatidylinositol 4,5-bisphosphate (PtdIns4,5P2) are radioactively labelled. The concentrations of PtdIns4P and PtdIns4,5P2 remain constant throughout the incubation, so this labelling process is a reflection of the steady-state turnover of their monoester phosphate groups. 3. During such incubations, the specific radioactivities of the monoesterified phosphates of PtdIns4, PtdIns4,5P2 and PtdOH come to a steady value after 5 h that is only 25-30% of the specific radioactivity of the gamma-phosphate of ATP at that time. We suggest that this is a consequence of metabolic heterogeneity. This heterogeneity is not a result of the heterogeneous age distribution of the erythrocytes in human blood. Thus it appears that there is metabolic compartmentation of these lipids within cells, such that within a time-scale of a few hours only 25-30% of these three lipids are actively metabolized. 4. The phosphoinositidase C of intact human erythrocytes, when activated by Ca2+-ionophore treatment, only hydrolyses 50% of the total PtdIns4,5P2 and 50% of 32P-labelled PtdIns4,5P2 present in the cells: this enzyme does not discriminate between the metabolically active and inactive compartments of lipids in the erythrocyte membrane. Hence at least four metabolic pools of PtdIns4P and PtdIns4,5P2 are distinguishable in the human erythrocyte plasma membrane. 5. The mechanisms by which multiple non-mixing metabolic pools of PtdOH, PtdIns4P and PtdIns4,5P2 are sustained over many hours in the plasma membranes of intact erythrocytes are unknown, although some possible explanations are considered.

scholarly journals Autoimmunity to phosphatidylserine and anemia in African Trypanosome infections

2021 ◽  
Vol 15 (9) ◽  
pp. e0009814
Author(s):  
Juan Rivera-Correa ◽  
Joseph Verdi ◽  
Julian Sherman ◽  
Jeremy M. Sternberg ◽  
Jayne Raper ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
B Cells ◽  
Trypanosoma Cruzi ◽  
Trypanosoma Brucei ◽  
Mouse Models ◽  
Human African Trypanosomiasis ◽  
Annexin V ◽  
Trypanosome Infection ◽  
Erythrocyte Plasma Membrane

Anemia caused by trypanosome infection is poorly understood. Autoimmunity during Trypanosoma brucei infection was proposed to have a role during anemia, but the mechanisms involved during this pathology have not been elucidated. In mouse models and human patients infected with malaria parasites, atypical B-cells promote anemia through the secretion of autoimmune anti-phosphatidylserine (anti-PS) antibodies that bind to uninfected erythrocytes and facilitate their clearance. Using mouse models of two trypanosome infections, Trypanosoma brucei and Trypanosoma cruzi, we assessed levels of autoantibodies and anemia. Our results indicate that acute T. brucei infection, but not T. cruzi, leads to early increased levels of plasma autoantibodies against different auto antigens tested (PS, DNA and erythrocyte lysate) and expansion of atypical B cells (ABCs) that secrete these autoantibodies. In vitro studies confirmed that a lysate of T. brucei, but not T. cruzi, could directly promote the expansion of these ABCs. PS exposure on erythrocyte plasma membrane seems to be an important contributor to anemia by delaying erythrocyte recovery since treatment with an agent that prevents binding to it (Annexin V) ameliorated anemia in T. brucei-infected mice. Analysis of the plasma of patients with human African trypanosomiasis (HAT) revealed high levels of anti-PS antibodies that correlated with anemia. Altogether these results suggest a relation between autoimmunity against PS and anemia in both mice and patients infected with T. brucei.

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