BACKGROUND Phosphatidylserine-expressing microparticles circulate in blood with a short half-life of <10 minutes. We tested the role of an endothelium-derived phosphatidylserine-binding opsonin, developmental endothelial locus-1 (Del-1), in the uptake of platelet microparticles. METHODS AND RESULTS Cultured human umbilical vein and microvascular endothelial cells avidly engulf BODIPY (4,4-dif...

Cepharanthine, a bisbenzylisoquinoline (biscoclaurine) alkaloid, completely overcomes resistance of a multidrug-resistant subline, ChR-24, derived from human KB carcinoma cells, to vincristine, actinomycin D, and daunomycin, and partially overcomes resistance to Adriamycin. Another biscoclaurine alkaloid, berbamine, partially overcomes resistance to these anticancer agents. Accumulation of [3H]...

The C2 domain of PKCα (C2α) induces fluorescence self-quenching of NBD-PS in the presence of Ca2+, which is interpreted as the demixing of phosphatidylserine from a mixture of this phospholipid with phosphatidylcholine. Self-quenching of NBD-PS was considerably increased when phosphatidylinositol-4,5-bisphosphate (PIP2) was present in the membrane. When PIP2 was the labeled phospholipid, in the...

BACKGROUND Sorafenib (Nexavar(®)), a polytyrosine kinase inhibitor, stimulates apoptosis and is thus widely used for chemotherapy in hepatocellular carcinoma (HCC). Hematological side effects of Nexavar(®) chemotherapy include anemia. Erythrocytes may undergo apoptosis-like suicidal death or eryptosis, which is characterized by cell shrinkage and phosphatidylserine-exposure at the cell surface....

A Zn-dipicolylamine coordination compound is shown to sense the presence of anionic phospholipids in a membrane bilayer. The sensor contains two dipicolylamine subunits attached to an anthracene scaffold, which exhibits a maximum absorbance at 380 nm, and undergoes an enhancement in fluorescence intensity when exposed to membranes enriched in phosphatidylserine. For these reasons, the compound ...

Phosphatidylserine decarboxylase, which is embedded in the inner mitochondrial membrane, synthesizes phosphatidylethanolamine (PE) and, in some cells, synthesizes the majority of this important phospholipid. Normal levels of PE can decline with age in the brain. Here we used yeast and worms to test the hypothesis that low levels of PE alter the homeostasis of the Parkinson disease-associated pr...

The transbilayer dynamics of lipids in the plasma membrane of mammalian sperm cells is crucial for the fertilization process. Here, the transbilayer movement and distribution of phospholipids in the plasma membrane of fresh, ejaculated and cryopreserved ram spermatozoa was studied by labeling cells with fluorescent analogues of phosphatidylserine and phosphatidylcholine. By co-labeling cells wi...

Background: Phosphatidylserine (PS) is a phospholipid normally located in the inner leaflet of the cell membrane. PS is translocated from the inner to the outer leaflet of the plasma membrane during the early stages of apoptosis and in necrosis. In cell and animal studies, reversible PS externalisation to the outer membrane leaflet has been observed in viable cells. Hence, PS markers have been ...

The importance of the various regions of the apocytochrome c molecule and the effect of covalent coupling of the heme group to the protein for the translocation across a model-membrane was studied by using chemically and enzymatically prepared fragments of horse heart apo- and holocytochrome c and model-membranes composed of phosphatidylserine and phosphatidylcholine. Binding experiments showed...

BACKGROUND Germ cell elimination and sperm DNA fragmentation in men with primary testiculopathies involve apoptosis-related processes whose mechanisms are poorly understood. This study examines the participation of typical (caspase-dependent) and atypical (caspase-independent) pathways in these processes. METHODS Caspase activity and DNA fragmentation were evaluated in Sertoli and germ cells ...