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The cholesterol content in erythrocytes expressing Miltenberger antigen subtype III (Mi.III) has limited effects on membrane deformability (LB161)
Author(s) -
Hsu Kate,
Yao ChinChe
Publication year - 2014
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.28.1_supplement.lb161
Subject(s) - glycophorin , erythrocyte fragility , band 3 , osmotic shock , osmotic concentration , membrane , red blood cell , cell membrane , chemistry , cholesterol , membrane protein , erythrocyte deformability , biophysics , biochemistry , biology , hemolysis , immunology , gene
The Miltenberger antigen subtype III (Mi.III, GP.Mur), is one of the most important red blood cell (RBC) antigens in Southeast Asia. GP.Mur is a glycophorin B‐A‐B fusion protein evolved from homologous recombination of glycophorin A and glycophorin B. We previously showed that GP.Mur in Mi.III+ cells enhances the expression of band 3, consequently facilitating Cl‐/HCO3‐ transport, CO2 respiration, and membrane resistance to osmotic stress. The aim of this study was to further investigate if the unique expressions of GP.Mur and band 3 in Mi.III also influenced cell membrane deformability. The methods utilized were osmotic gradient ektacytometry, osmotic fragility tests and Amplex Red Cholesterol assay. A total of 114 fresh RBC samples, including 50 Mi.III+ and 64 non‐Mi.III (control), were evaluated. From osmolarity fragility tests, Mi.III+ RBCs consistently exhibited superior resistance to osmotic stress. Mi.III+ RBCs however were less deformable than the control cells. The discordance between the results of membrane deformability and membrane's resistance to osmotic stress suggests that the higher band 3 expression on the Mi.III membrane likely affect the physical properties of the membrane through higher densities of band 3 interactions with adjacent lipids and cytoskeletal proteins. We also only observed the rigidifying effects of cholesterol on membrane deformability in the control cells, and not in Mi.III. We thus conclude that in contrast to the non‐Miltenberger RBCs, the cholesterol content of Mi.III+ cells has relatively limited effects on membrane deformability, presumably due to the higher band 3 levels on the Mi.III membrane. Grant Funding Source : Supported by Taiwan National Health Research Institute, NHRI‐EX102‐10122SI