Phosphatidic acid metabolism in rat liver cell nuclei

AbstractThe aim of the present research was to analyze the pathways for phosphatidic acid metabolism in purified nuclei from liver. Lipid phosphate phosphatase, diacylglycerol lipase, monoacylglycerol lipase and PA-phospholipase type A activities were detected. The presence of lysophosphatidic acid significantly reduced DAG production while sphingosine 1-phoshate and ceramide 1-phosphate reduced MAG formation from PA. Using different enzymatic modulators (detergents and ions) an increase in the PA metabolism by phospholipase type A was observed. Our findings evidence an active PA metabolism in purified liver nuclei which generates important lipid second messengers, and which could thus be involved in nuclear processes such as gene transcription

Regulation of Phosphatidic Acid Metabolism by Sphingolipids in the Central Nervous System

This paper explores the way ceramide, sphingosine, ceramide 1-phosphate, and sphingosine 1-phosphate modulate the generation of second lipid messengers from phosphatidic acid in two experimental models of the central nervous system: in vertebrate rod outer segments prepared from dark-adapted retinas as well as in rod outer segments prepared from light-adapted retinas and in rat cerebral cortex synaptosomes under physiological aging conditions. Particular attention is paid to lipid phosphate phosphatase, diacylglycerol lipase, and monoacylglycerol lipase. Based on the findings reported in this paper, it can be concluded that proteins related to phototransduction phenomena are involved in the effects derived from sphingosine 1-phosphate/sphingosine or ceramide 1-phosphate/ceramide and that age-related changes occur in the metabolism of phosphatidic acid from cerebral cortex synaptosomes in the presence of either sphingosine 1-phosphate/sphingosine or ceramide 1-phosphate/ceramide. The present paper demonstrates, in two different models of central nervous system, how sphingolipids influence phosphatidic acid metabolism under different physiological conditions such as light and aging

El estímulo lumínico modula el metabolismo del 2-araquidonoil glicerol en los segmentos externos de los bastones de la retina bovina

El 2-araquidonoil glicerol (2-AG) es un endocannabinoide de naturaleza lipídica que puede unirse a receptores cannabinoides. Está involucrado en mecanismos intracelulares de gran relevancia, y cumple funciones neuromoduladoras y neuroprotectoras. La principal ruta metabólica para la síntesis del 2-AG involucra la acción combinada de una fosfolipasa C (PLC) y una diacilglicerol lipasa (DAGL). Otra vía de formación de 2-AG es a partir del 2-araquidonoil lisofosfatidato (2-araquidonoilLPA) por la acción de una lisofosfatidato fosfohidrolasa (LPAPasa).Fil: Chamorro Aguirre , Estefania. Consejo Nacional de Investigaciones Científicas y TécnicasFil: Gaveglio, Virginia L.. Consejo Nacional de Investigaciones Científicas y TécnicasFil: Pasquaré, Susana J. . Consejo Nacional de Investigaciones Científicas y Técnica

The catalytic efficiency of Lipin 1beta increases by physically interacting with the protooncoprotein c-Fos

Phosphatidic acid (PA) is a central precursor for membrane phospholipid biosynthesis. Lipin family is a Mg-dependent type I PA phosphatase,involved in de novo synthesis of neutral lipids and of phospholipids. The regulation of Lipin activity may govern the pathways by which these lipids aresynthesized and control the cellular levels ofimportant signaling lipids. On the other hand, the proto-oncoprotein c-Fos has an emerging role in glycerolipid synthesis regulation: by interacting with key synthetizing enzymes it is able toincrease overall phopho- and glyco- lipid synthesis.We studied the Lipin 1β enzyme activity in a cell-free system using PA/Triton X-100 mixed micelles as substrate, analyzing it in the presence/absence of c-Fos. We found that Lipin 1β kcat increases around 40% in the presence of c- Fos, with no change in the Lipin 1β affinity for the PA/Triton X-100 mixed micelles. We also probed a physical interaction between both proteins. While the c-Fos domain involved in Lipin activation is its basic domain (BD), the interaction domain is mapped to the c-Fos N-terminal. In conclusion, we provide evidence for a novel positive regulator of Lipin 1β PA phosphatase activity that is not achieved via altering its subcellular localization or affinity for membranesbut rather through directly increasing its catalytic efficiency.Fil: Cardozo Gizzi, Andres Mauricio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones En Química Biológica de Córdoba (p); ArgentinaFil: Prucca, Cesar German. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones En Química Biológica de Córdoba (p); ArgentinaFil: Gaveglio, Virginia Lucía. Consejo Nacional de Investigaciones Cientificas y Técnicas. Centro Científico Tecnológico Bahia Blanca. Instituto de Investigaciones Bioquímicas Bahia Blanca (i); ArgentinaFil: Renner, Marianne L.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Química Biológica de Córdoba (p); ArgentinaFil: Pasquaré, Susana J.. Consejo Nacional de Investigaciones Cientificas y Técnicas. Centro Científico Tecnológico Bahia Blanca. Instituto de Investigaciones Bioquímicas Bahia Blanca (i); ArgentinaFil: Caputto, Beatriz Leonor. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones En Química Biológica de Córdoba (p); Argentin