The CHO1-encoded phosphatidylserine synthase (CDP-diacylglycerol:l-serine O-phosphatidyltransferase, EC 2.7.8.8) is one of the most highly regulated phospholipid biosynthetic enzymes in the yeast Saccharomyces cerevisiae. CHO1 expression is regulated by nutrient availability through a regulatory circuit involving a UAS(INO) cis-acting element in the CHO1 promoter, the positive transcription fac...

Anti-A IgG antibodies have previously been shown to stimulate Ca(2+) entry into red blood cells. Increased cytosolic free Ca(2+) concentration is known to trigger eryptosis, i.e. suicidal erythrocyte death, characterized by exposure of phosphatidylserine at the erythrocyte surface. As macrophages are equipped with phosphatidylserine receptors, they bind, engulf and degrade phosphatidylserine ex...

Suicidal death of erythrocytes, or eryptosis, is characterized by cell shrinkage and cell membrane scrambling leading to phosphatidylserine exposure at the cell surface. Eryptosis is triggered by increase of cytosolic Ca2+ activity, which may result from treatment with the Ca2+ ionophore ionomycin or from energy depletion by removal of glucose. The present study tested the hypothesis that phosp...

Temperature-sensitive conditional lethal mutants in phosphatidylserine decarboxylase (psd) accumulate large amounts of phosphatidylserine under nonpermissive conditions (42°C) prior to cell death. In addition, the ratio of cardiolipin to phosphatidylglycerol is increased. At an intermediate temperature (37”C), high levels of phosphatidylserine can be maintained with little effect on cell growth...

Phosphatidylserine from human plasma was purified and identified by amino normal-phase and octadecylsilyl reversed-phase high-performance liquid chromatography, respectively. The two major molecular species within the human plasma phosphatidylserine, qualitatively determined by negative-ion fast atom bombardment mass spectrometry, are 1-stearoyl-2-oleoyl-sn-glycero-3-phosphoserine and 1-stearoy...

Lipid-anchored Ras GTPases form transient, spatially segregated nanoclusters on the plasma membrane that are essential for high-fidelity signal transmission. The lipid composition of Ras nanoclusters, however, has not previously been investigated. High-resolution spatial mapping shows that different Ras nanoclusters have distinct lipid compositions, indicating that Ras proteins engage in isofor...

In the yeast Saccharomyces cerevisiae, the most abundant phospholipid phosphatidylcholine is synthesized by the complementary CDP-diacylglycerol and Kennedy pathways. Using a cki1Delta eki1Delta mutant defective in choline kinase and ethanolamine kinase, we examined the consequences of a block in the Kennedy pathway on the regulation of phosphatidylcholine synthesis by the CDP-diacylglycerol pa...

Eryptosis, the suicidal erythrocyte death, leads to cell shrinkage and cell membrane scrambling with phosphatidylserine exposure at the cell surface. Eryptotic erythrocytes adhere to the vascular wall by binding of phosphatidylserine to the CXC chemokine ligand 16 (CXCL16). Stimulators of eryptosis include increased cytosolic Ca(2+) activity, energy depletion, and activation of ceramide-produci...

A recent study of the diffusion of univalent ions across lamellae of swollen phosphatidylcholine "liquid crystals" demonstrated the potentialities of such structures as model phospholipid membranes of well defined molecular structure and composition 1. As a continuation of these studies, it was thought that phosphatidylserine, with its additional functional groups and net negative charge, might...

Phosphatidylserine was exposed on the surface of human umbilical endothelial cells (ECV304) a few minutes after adding thrombin in vitro, as monitored by prothrombinase assays with and without annexin V. Jurkat T cells adhered to the thrombin-treated cells. The adhesion was inhibited by annexin V, indicating that it was mediated by exposed phosphatidylserine on the endothelial cells.