Manipulation of the phosphatidylethanolamine pool in the human red cell membrane affects its Mg²⁺-ATPase activity

Abstract

Decreasing the size of the outer leaflet pool of phosphatidylethanolamine (PE) in the erythrocyte membrane by treatment of intact cells with either phospholipase A2, or trinitrobenzenesulphonic acid (TNBS), causes a corresponding decrease in Mg(2+)-ATPase activity as determined in their respective ghosts. Also, incubation of ghosts with Ro09-0198, a cyclic peptide from Streptoverticillium which is known to interact specifically with PE, causes a decrease in Mg(2+)-ATPase activity which is dependent on the amount of peptide added. These three different approaches, all causing a decrease in endogenous PE, thus result in a concomitant decrease in Mg(2+)-ATPase activity which reaches a plateau level at approximately 25% residual activity. Hence, it is inferred that the complementary fraction (75%) of the total Mg(2+)-ATPase in the red cell membrane is closely related to the functioning of its aminophospholipid specific translocase as it mediates a (continuous) transport of PE molecules from outer to inner membrane leaflet. This view is supported by the observation that an increase in the total amount of PE in the membrane by decarboxylation of an appreciable fraction of its PS, results in a considerable increase in Mg(2+)-ATPase activity.

The biochemical modification of the erythrocyte membranes from women with ovarian cancer

“…SPH plays a fundamental role in this reconstruction because the hydrogen bonds it forms between the neighbouring molecules may regulate erythrocyte membrane condition (Schwartz et al, 1985). Another hypothesis proposes that SPH assymetric distribution is supported by the ATP-dependent system of PS translocation into inner monolayer and PS interaction with membrane cytoskeleton proteins (Vermeulen, 1996). Spectrin, as a main element of the cytoskeleton joins the membrane phospholipids by molecules of ankiryn, actin and 4.1 band protein and affects hydrophobic zone lipid bilayer settlement (Manno et al, 1995).…”