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

The mouse liver displays daily rhythms in the metabolism of phospholipids and in the activity of lipis synthesizing enzymes

The circadian system involves central and peripheral oscillators regulating temporally biochemical processes including lipid metabolism; their disruption leads to severe metabolic diseases (obesity, diabetes, etc). Here, we investigated the temporal regulation of glycerophospholipid (GPL) synthesis in mouse liver, a well-known peripheral oscillator. Mice were synchronized to a 12:12 h light?dark (LD) cycle and then released to constant darkness with food ad libitum. Livers collected at different times exhibited a daily rhythmicity in some individual GPL content with highest levels during the subjective day. The activity of GPL-synthesizing/remodeling enzymes: phosphatidate phosphohydrolase 1 (PAP-1/lipin) and lysophospholipid acyltransferases (LPLATs) also displayed significant variations, with higher levels during the subjective day and at dusk. We evaluated the temporal regulation of expression and activity of phosphatidylcholine (PC) synthesizing enzymes. PC is mainly synthesized through the Kennedy pathway with Choline Kinase (ChoK) as a key regulatory enzyme or through the phosphatidylethanolamine (PE) N-methyltransferase (PEMT) pathway. The PC/PE content ratio exhibited a daily variation with lowest levels at night, while ChoKα and PEMT mRNA expression displayed maximal levels at nocturnal phases. Our results demonstrate that mouse liver GPL metabolism oscillates rhythmically with a precise temporal control in the expression and/or activity of specific enzymes.Fil: Gorne, Lucas Damián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones En Química Biológica de Córdoba (p); Argentina. Universidad Nacional de Córdoba; ArgentinaFil: Acosta Rodríguez, Victoria América. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones En Química Biológica de Córdoba (p); Argentina. Universidad Nacional de Córdoba; ArgentinaFil: Pasquaré, Susana J.. Consejo Nacional de Investigaciones Cientificas y Técnicas. Centro Científico Tecnológico Bahia Blanca. Instituto de Investigaciones Bioquímicas Bahia Blanca (i); Argentina. Universidad Nacional del Sur; ArgentinaFil: Salvador, Gabriela Alejandra. Consejo Nacional de Investigaciones Cientificas y Técnicas. Centro Científico Tecnológico Bahia Blanca. Instituto de Investigaciones Bioquímicas Bahia Blanca (i); Argentina. Universidad Nacional del Sur; ArgentinaFil: Giusto, Norma Maria. Consejo Nacional de Investigaciones Cientificas y Técnicas. Centro Científico Tecnológico Bahia Blanca. Instituto de Investigaciones Bioquímicas Bahia Blanca (i); Argentina. Universidad Nacional del Sur; ArgentinaFil: Guido, Mario Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones En Química Biológica de Córdoba (p); Argentina. Universidad Nacional de Córdoba; Argentin

Differences in phosphatidic acid signalling and metabolism between ABA and GA treatments of barley aleurone cells

Phosphatidic acid (PA) is the common lipid product in abscisic acid (ABA) and gibberellic acid (GA)response. In this work we investigated the lipid metabolism in response to both hormones. We could detect an in vivo phospholipase D activity (PLD, EC 3.1.4.4). This PLD produced [32P]PA (phosphatidic acid) rapidly (minutes) in the presence of ABA, confirming PA involvement in signal transduction, and transiently, indicating rapid PA removal after generation. The presence of PA removal by phosphatidate phosphatase 1 and 2 isoforms (E.C. 3.1.3.4) was verified in isolated aleurone membranes in vitro, the former but not the latter being Specifically responsive to the presence of GA or ABA. The in vitro DGPP phosphatase activity was not modified by short time incubation with GA or ABA while the in vitro PA kinase e that allows the production of 18:2-DGPP from 18:2-PA e is stimulated by ABA. The long term effects (24 h) of ABA or GA on lipid and fatty acid composition of aleurone layer cells were then investigated. An increase in PC and, to a lesser extent, in PE levels is the consequence of both hormone treatments. ABA, in aleurone layer cells, specifically activates a PLD whose product, PA, could be the substrate of PAP1 and/or PAK activities. Neither PLD nor PAK activation can be monitored by GA treatment. The increase in PAP1 activity monitored after ABA or GA treatment might participate in the increase in PC level observed after 24 h hormone incubationFil: Villasuso, Ana Laura. Universidad Nacional de Rio Cuarto; ArgentinaFil: Di Palma, María Albana. Universidad Nacional de Rio Cuarto; ArgentinaFil: Aveldaño, Marta Isabel. Consejo Nacional de Investigaciones Cientificas y Técnicas. Centro Científico Tecnológico Bahia Blanca. Instituto de Investigaciones Bioquímicas Bahia Blanca (i); ArgentinaFil: Pasquaré, Susana J.. Consejo Nacional de Investigaciones Cientificas y Técnicas. Centro Científico Tecnológico Bahia Blanca. Instituto de Investigaciones Bioquímicas Bahia Blanca (i); ArgentinaFil: Racagni, Graciela. Universidad Nacional de Rio Cuarto; ArgentinaFil: Giusto, Norma Maria. Consejo Nacional de Investigaciones Cientificas y Técnicas. Centro Científico Tecnológico Bahia Blanca. Instituto de Investigaciones Bioquímicas Bahia Blanca (i); ArgentinaFil: Machado, Estela E.. Universidad Nacional de Rio Cuarto; Argentin