Serum-free cultured neuroblastoma cells (clone NlE-115) have been shown to absorb emulsified glucosylceramide, glucosylceramide glucosidase, an activator protein for the enzyme, and phosphatidylserine from a synthetic medium. Uptake of the enzyme was augmented by phosphatidylserine, and vice versa. Uptake of the enzyme-lipid complex was further augmented by the activator protein. It appears lik...

Halothane and propofol stimulate activation of protein kinase C (PKC) in the presence of physiologically relevant lipid bilayer vesicles in vitro. The mechanism of this stimulation was characterized by analyzing the effects of halothane and propofol on the activation of purified rat brain PKC by its three essential activators, phosphatidylserine, diacylglycerol, and Ca’+, each of which is known...

Apoptosis, or programmed cell death, is a general mechanism for removal of unwanted cells from the immune system. It is characterized by chromatin condensation, a reduction in cell volume, and endonuclease cleavage of DNA into oligonucleosomal length fragments. Apoptosis is also accompanied by a loss of membrane phospholipid asymmetry, resulting in the exposure of phosphatidylserine at the surf...

Protein kinase C activity towards exogenous histone was detected in a cytosolic fraction of bovine adrenal medulla. The enzyme was dependent on Ca2+ and phosphatidylserine for its activity, with half-maximal activation being achieved at approx. 18 microM free Ca2+ and 8 micrograms of phosphatidylserine/ml. Both diolein and 4 beta-phorbol 12-myristate 13-acetate (TPA) decreased the Ca2+ requirem...

Palmitoylcarnitine, which has been reported to be an inhibitor of calcium-activated, phospholipid-dependent protein kinase (protein kinase C), inhibited 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced epidermal ornithine decarboxylase in mouse skin in a dose-dependent manner. Neither acetylcarnitine nor palmitic acid inhibited TPA-caused ornithine decarboxylase induction. In addition, palmit...

We have recently described the preparation of a solubilized cat myocardial adenylate cyclase which is unresponsive to histamine, norepinephrine, glucagon, and thyroxine, the hormones which activate the particulate enzyme. Since hormone receptors may consist of proteins and phospholipids, we determined the effect of several phospholipids on restoring the responsiveness of the solubilized adenyla...

Much has been learned about the role of exofacial phosphatidylserine (PS) in apoptosis and blood clotting using annexin V. However, because annexins are impermeant and unable to bind PS at low calcium concentration, they are unsuitable for intracellular use. Thus little is known about the topology and dynamics of PS in the endomembranes of normal cells. We used two new probes-green fluorescent ...