Application of the Wang–Landau algorithm to the dimerization of glycophorin A

We have investigated the effect of integral membrane proteins upon the fracturing of frozen lipid bilayers. This investigation has been part of an effort to develop freeze fracture labeling techniques and to assess the possible breakage of covalent protein bonds during the freeze fracture process. We have developed an experimental protocol utilizing lectin affinity columns which should detect small amounts of covalent bond breakage during the fracture of liposomes containing purified (1) glycophorin (a transmembrane glycoprotein of human erythrocyte membranes). To fracture liposomes in bulk, frozen liposomes are ground repeatedly under liquid nitrogen. Failure to detect any significant covalent bond breakage (contrary to (2)) led us to question the effectiveness of our grinding procedure in fracturing and splitting lipid bilayers.

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Glycophorin A facilitates the expression of human band 3-mediated anion transport in Xenopus oocytes.

Journal of Biological Chemistry ◽

10.1016/s0021-9258(18)41649-3 ◽

1992 ◽

Vol 267 (31) ◽

pp. 22163-22170

Author(s):

J.D. Groves ◽

M.J. Tanner

Keyword(s):

Xenopus Oocytes ◽

Band 3 ◽

Anion Transport ◽

Glycophorin A

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Glycophorin A-based exclusion of red blood cells for flow cytometric analysis of platelet glycoprotein expression in citrated whole blood

Clinical Chemistry and Laboratory Medicine (CCLM) ◽

10.1515/cclm-2020-0014 ◽

2020 ◽

Vol 0 (0) ◽

Author(s):

Christina Berens ◽

Johannes Oldenburg ◽

Bernd Pötzsch ◽

Jens Müller

Keyword(s):

Red Blood Cells ◽

Expression Analysis ◽

Whole Blood ◽

Blood Cells ◽

Control Sample ◽

Small Sample ◽

Platelet Glycoprotein ◽

Glycophorin A ◽

Giant Platelets ◽

Platelet Counts

AbstractObjectivesAnalysis of platelet glycoprotein (GP) expression by flow cytometry is applied for diagnostic confirmation of GP-associated thrombocytopathies. While platelet-rich plasma may be used for distinct identification of target events, this strategy is not feasible for small sample volumes or for patients showing low platelet counts and/or giant platelets. However, also the use of whole blood (WB) is hampered by the difficulty to discriminate platelets from red blood cells (RBC) in such patients. To circumvent these limitations, we evaluated the feasibility of a RBC gating-out strategy.MethodsIn addition to platelet GPIb, GPIIa/IIIa, as well as P-selectin (CD62P), citrated whole blood (CWB) samples were stained for RBC-specific glycophorin A (CD235a). CD235a-negative platelet events were further discriminated by forward-/side-scatter characteristics and platelet GP expressions analyzed relative to that of a healthy control sample processed in parallel.ResultsEstablished reference intervals allowed for clear identification of decreased GPIIb/IIIa- or GPIb expression pattern in samples of patients with confirmed Glanzmann thrombasthenia or Bernard–Soulier syndrome, respectively. It could be shown that the analysis of 2,500 platelet events is sufficient for reliable GP expression analysis, rendering the proposed method applicable to samples with low platelet counts.ConclusionsThis study demonstrates the feasibility of CD235a-based exclusion of RBC for platelet GP expression analysis in CWB. In contrast to direct staining of platelet-specific antigens for target identification, this indirect gating out approach is generally applicable independent of any underlying platelet GP expression deficiency.

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Diagnostic value of glycophorin-A in comparison with P57 immunohistochemical staining method in differentiating complete and partial molar pregnancies

Annals of Diagnostic Pathology ◽

10.1016/j.anndiagpath.2021.151769 ◽

2021 ◽

pp. 151769

Author(s):

Fatemeh Nili ◽

Sara Babazadeh ◽

Soheila Sarmadi ◽

Fereshteh Ameli ◽

Hana Saffar

Keyword(s):

Immunohistochemical Staining ◽

Staining Method ◽

Diagnostic Value ◽

Glycophorin A

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Interactions of mouse glycophorin A with the dRTA-related mutant G719D of the mouse Cl–/HCO3– exchanger Ae1This paper is one of a selection of papers published in a Special Issue entitled CSBMCB 53rd Annual Meeting — Membrane Proteins in Health and Disease, and has undergone the Journal’s usual peer review process.

Biochemistry and Cell Biology ◽

10.1139/o10-147 ◽

2011 ◽

Vol 89 (2) ◽

pp. 224-235 ◽

Cited By ~ 2

Author(s):

Andrew K. Stewart ◽

Fouad T. Chebib ◽

Syed W. Akbar ◽

Maria J. Salas ◽

Rajan A. Sonik ◽

...

Keyword(s):

Amino Acids ◽

Transmembrane Domain ◽

Peer Review Process ◽

Surface Expression ◽

Amino Acid Sequences ◽

Glycophorin A ◽

Specific Expression ◽

Health And Disease ◽

Renal Tubular

The AE1 mutation G701D, associated with recessive distal renal tubular acidosis (dRTA), produces only minimal erythroid phenotype, reflecting erythroid-specific expression of stimulatory AE1 subunit glycophorin A (GPA). GPA transgene expression could theoretically treat recessive dRTA in patients and in mice expressing cognate Ae1 mutation G719D. However, human (h) GPA and mouse (m) Gpa amino acid sequences are widely divergent, and mGpa function in vitro has not been investigated. We therefore studied in Xenopus oocytes the effects of coexpressed mGpa and hGPA on anion transport by erythroid (e) and kidney (k) isoforms of wild-type mAe1 (meAe1, mkAe1) and of mAe1 mutant G719D. Coexpression of hGPA or mGpa enhanced the function of meAe1 and mkAe1 and rescued the nonfunctional meAe1 and mkAe1 G719D mutants through increased surface expression. Progressive N-terminal truncation studies revealed a role for meAe1 amino acids 22–28 in GPA-responsiveness of meAe1 G719D. MouseN-cyto/humanTMD and humanN-cyto/mouseTMD kAE1 chimeras were active and GPA-responsive. In contrast, whereas chimera mkAe1N-cyto/hkAE1 G701DTMD was GPA-responsive, chimera hkAE1N-cyto/mkAe1 G719DTMD was GPA-insensitive. Moreover, whereas the isolated transmembrane domain (TMD) of hAE1 G701D was GPA-responsive, that of mAe1 G719D was GPA-insensitive. Thus, mGpa increases surface expression and activity of meAe1 and mkAe1. However, the G719D mutation renders certain mAe1 mutant constructs GPA-unresponsive and highlights a role for erythroid-specific meAe1 amino acids 22–28 in GPA-responsiveness.

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