Spectrin and Other Membrane-Skeletal Components in Human Red Blood Cells of Different Age.

Old human red blood cells (RBCs) have a reduced surface area with respect to young RBCs. If this decrease occurred through the release of vesicles similar to the spectrin-free vesicles that are shed in vitro under different experimental conditions or during storage, there would be no decrease of membrane-skeleton, but only of lipid bilayer surface area, during RBC ageing in vivo. However, we observed a decrease in spectrin and other membrane-skeletal proteins in old RBCs. Because RBCs contain components of the ubiquitin-proteasome system and other hydrolytic systems for protein degradation, we asked whether increased membrane-skeleton fragments could be detected in older RBCs. Four different anti-spectrin antibodies and an antibody anti-ubiquitin conjugates were used to analyse, by Western blotting, fragments of spectrin and other proteins in RBCs of different age separated in density gradients and characterized for their protein 4.1a/4.1b ratio as a cell age parameter. spectrin fragments do exist in RBCs of all ages, they represent a minute fraction of all spectrin, are membrane-bound and not cytoplasmic and do not increase with cell age. Besides spectrin, other membrane-skeletal components decrease with cell age. Observed results challenge the commonly accepted view that decrease in cell membrane throughout RBC life in vivo occurs via the release of spectrin-free vesicles. © 2017 The Author(s). Published by S. Karger AG, Basel.

Citation

Annarita Ciana, Cesare Achilli, Giampaolo Minetti. Spectrin and Other Membrane-Skeletal Components in Human Red Blood Cells of Different Age. Cellular physiology and biochemistry : international journal of experimental cellular physiology, biochemistry, and pharmacology. 2017;42(3):1139-1152

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PMID: 28668958

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