Regulation of Phosphatidylserine Exposure in Red Blood Cells

Cellular Physiology and Biochemistry

关键词: Red blood cells;    Lysophosphatidic acid;    Scramblase;    Flippase;    Calcium concentration;    Phosphatidylserine;    Fluorescence imaging;   

DOI  :  10.1159/000335798

学科分类：分子生物学，细胞生物学和基因

来源: S Karger AG

【 摘 要 】

The exposure of phosphatidylserine (PS) on the outer membrane leaflet of red blood cells (RBCs) serves as a signal for eryptosis, a mechanism for the RBC clearance from blood circulation. The process of PS exposure was investigated as function of the intracellular Ca²⁺ content and the activation of PKCα in human and sheep RBCs. Cells were treated with lysophosphatidic acid (LPA), 4-bromo-A23187, or phorbol-12 myristate-13 acetate (PMA) and analysed by flow cytometry, single cell fluorescence video imaging, or confocal microscopy. For human RBCs, no clear correlation existed between the number of cells with an elevated Ca²⁺ content and PS exposure. Results are explained by three different mechanisms responsible for the PS exposure in human RBCs (i) Ca²⁺-stimulated scramblase activation (and flippase inhibition) by LPA, 4-bromo-A23187, and PMA; (ii) PKC activation by LPA and PMA; and (iii) enhanced lipid flop caused by LPA. In sheep RBCs, only the latter mechanism occurs suggesting absence of scramblase activity.

【 授权许可】

CC BY-NC-ND