The concentration-dependence on exogenous ATP of activation and inhibition of mast-cell histamine secretion, phosphatidylinositol labelling and leakage of metabolites shows that all these functions are regulated by the free acid ATP4-. Maximal histamine secretion and phosphatidylinositol labelling occur with ATP4- at approx. 2 microM, but higher concentrations, which cause inhibition of secreti...

The Saccharomyces cerevisiae SAC1 gene was identified via independent analyses of mutations that modulate yeast actin function and alleviate the essential requirement for phosphatidylinositol transfer protein (Sec14p) activity in Golgi secretory function. The SAC1 gene product (Sac1p) is an integral membrane protein of the endoplasmic reticulum and the Golgi complex. Sac1p shares primary sequen...

The transforming protein of polyoma virus, middle T antigen, associates with two cellular enzymes, pp60c-src, a protein tyrosine kinase, and a phosphatidylinositol kinase that forms phosphatidylinositol 3-phosphate. The formation of a ternary complex of these proteins is essential for complete transformation and maximal tumor induction by the virus. A mutant virus encoding an altered middle T p...

The major pathway by which liver lysosomal enzymes degrade phosphatidylinositol is through an EDTA-insensitive formation of phosphorylinositol. This is in distinct contrast with the Ca2+-dependent production of phosphorylinositol from phosphatidylinositol, which is located in the cytosol. Lysosomal enzymes can also totally deacylate phosphatidylinositol, producing glycerophosphorylinositol.

Phosphoinositides (PIPs) are key regulators of membrane traffic and signaling. The interconversion of PIPs by lipid kinases and phosphatases regulates their functionality. Phosphatidylinositol (PI) and PIPs have a unique enrichment of 1-stearoyl-2-arachidonyl acyl species; however, the regulation and function of this specific acyl profile remains poorly understood. We examined the role of the P...

Liposome vesicles could be formed at 65 degrees C from the chloroform-soluble, total polar lipids (TPL) extracted from Mycobacterium bovis bacillus Calmette-Guérin (BCG). Mice immunized with ovalbumin (OVA) entrapped in TPL liposomes produced both anti-OVA antibody and cytotoxic T lymphocyte responses. Murine bone marrow-derived dendritic cells were activated to secrete interleukin-6 (IL-6), IL...