Effect of Light on Phosphatidate Phosphohydrolase Activity of Retina Rod Outer Segments: The Role of Transducin

Pasquaré, Susana J.; Salvador, Gabriela Alejandra; Roque, Marta Elena; Giusto, Norma M.

doi:10.1006/abbi.2000.1861

Cited by 12 publications

(20 citation statements)

References 58 publications

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“…When the effect of light on LPP activity was evaluated using only [2- 3 H]PA as substrate, a marked inhibition of DAG and MAG production was observed in LROS with respect to DROS ( 156 ). The effect of light on LPP activities in ROS obtained from DROS has been previously demonstrated ( 76 ). The signifi cant inhibition of LPP activity caused by light and the absence of differences in LPP3 levels between DROS and LROS could be related either to the absence or the presence of a specifi c protein affected by light-driven translocation ( 156 ).…”

Section: Lppmentioning

confidence: 76%

“…ADP-ribosylation by CTx inhibited LPP activity with respect to dark control conditions, mimicking the effect of light. All these fi ndings demonstrate that light inhibition of LPP activity in ROS is a Gt-mediated mechanism ( 76 ).…”

Section: Pldmentioning

confidence: 83%

“…The activities of enzymes involved in ROS phospholipid turnover such as PLC ( 3,46,68,69 ), phospholipase A2 (PLA2) ( 70 ), phosphatidylethanolamine N-methyltransferase (PEMT) ( 71 ), diacylglycerol kinase (DAGK) (72)(73)(74)(75), lipid phosphate phosphatase (LPP) ( 76 ), diacylglycerol lipase (DAGL) ( 77,78 ), PI synthase ( 79 ), phosphoinositide-3-kinase (PI3K) ( 80,81 ), and PLD ( 82 ) have been reported to be modulated by light. Detailed studies on PI3K signaling are described by Rajala in the thematic review in this series on PI3K in the vertebrate retina.…”

Section: Light Regulation Of Enzymes Related To the Generation Of Secmentioning

confidence: 99%

“…DAGL is coupled to LPP and it would appear that these enzyme activities occur in a sort of enzyme complex in which DAG generation and its partial degradation by DAGL immediately occurs. On this premise, DAGL activity has been described in isolated vertebrate ROS (76)(77)(78)160 ). DAGL is also strongly linked to the following signaling functions: a ) in platelets, in response to thrombin their combined action with PLC facilitates the release of arachidonic acid ( 168 ); and b ) in neurons, this activity is necessary for the generation of endocannabinoid 2-arachidonoyl-glycerol during retrograde synaptic transmission ( 169 ).…”

Section: Daglmentioning

confidence: 99%

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Lipid second messengers and related enzymes in vertebrate rod outer segments

Giusto

Pasquaré

Salvador

et al. 2010

Journal of Lipid Research

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outer segment of the cell is comprised of a stack of many hundreds of densely packed discs, each of which represents a double layer of infolded plasma membrane. It has been suggested that phospholipid moieties in these membranes are metabolically active and are closely involved in the generation of physiological mediators. Modifi cations in the metabolism of photoreceptor membrane glycerolipids have been linked to the transduction of visual stimuli ( 3 ). Rod outer segment (ROS) membranes are composed of 50% protein and 50% lipid, by weight ( 2 ). Phospholipids and cholesterol represent nearly 90-95% and 4-6% (w/w) of total lipids, respectively. Rhodopsin accounts for at least 80-85% (w/w) of the total proteins ( 4-6 ) in disc ROS membranes. The rest are mainly proteins involved in phototransduction. The composition of mammalian ROS membrane phospholipids indicates that the major phospholipids are phosphatidylethanolamine (PE) and phosphatidylcholine (PC), along with relatively large amounts of phosphatidylserine (PS) (15%). Small amounts (less than 1% each) of sphingomyelin, phosphatidylinositol (PI) and phosphatidic acid (PA) are found in these membranes ( 7-13 ). In vertebrates, cholesterol (exclusively as the free sterol) is the principal neutral lipid, comprising The vertebrate photoreceptor cell is composed of different cellular compartments [outer segment (OS), inner segment (IS), and synaptic terminal (ST)], all of which differ in their lipid and protein content ( 1, 2 ). The photoreceptor is a highly specialized cell that responds to light stimulus and transmits this response to adjoining neurons for ultimate relay to the visual centers of the brain. TheThis work was supported

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Section: Lppmentioning

confidence: 76%

Section: Pldmentioning

confidence: 83%

Section: Light Regulation Of Enzymes Related To the Generation Of Secmentioning

confidence: 99%

Section: Daglmentioning

confidence: 99%

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Lipid second messengers and related enzymes in vertebrate rod outer segments

Giusto

Pasquaré

Salvador

et al. 2010

Journal of Lipid Research

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“…It has also been reported that transducin, arrestin and recoverin [7][8][9][10] are proteins involved in this mechanism. Previous studies revealed the presence of phosphatidate phosphohydrolase 2 (PAP2, renamed as LPPs) and its regulation in isolated ROS from bovine retina [11][12][13][14]. In this work, the generation of [2-3 H]DAG from [2-3 H]PA was analyzed either in the absence or in the presence of LPA, S1P or C1P, all of which are alternative substrates for LPPs.…”

Section: Introductionmentioning

confidence: 99%

Involvement of Lysophosphatidic Acid, Sphingosine 1-Phosphate and Ceramide 1-Phosphate in the Metabolization of Phosphatidic Acid by Lipid Phosphate Phosphatases in Bovine Rod Outer Segments

2008

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The aim of the present research was to evaluate the generation of [2-3H]diacylglycerol ([2-3H]DAG) from [2-3H]-Phosphatidic acid ([2-3H]PA) by lipid phosphate phosphatases (LPPs) at different concentrations of lysophosphatidic acid (LPA), sphingosine 1-phosphate (S1P), and ceramide 1-phosphate (C1P) in purified ROS obtained from dark-adapted retinas (DROS) or light-adapted retinas (BLROS) as well as in ROS membrane preparations depleted of soluble and peripheral proteins. Western blot analysis revealed the presence of LPP3 exclusively in all membrane preparations. Immunoblots of entire ROS and depleted ROS did not show dark-light differences in LPP3 levels. LPPs activities were diminished by 53% in BLROS with respect to DROS. The major competitive effect on PA hydrolysis was exerted by LPA and S1P in DROS and by C1P in BLROS. LPPs activities in depleted ROS were similar to the activity observed in entire DROS and BLROS, respectively. LPA, S1P and C1P competed at different extent in depleted DROS and BLROS. Sphingosine and ceramide inhibited LPPs activities in entire and depleted DROS. Ceramide also inhibited LPPs activities in entire and in depleted BLROS. Our findings are indicative of a different degree of competition between PA and LPA, S1P and C1P by LPPs depending on the illumination state of the retina.

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Synthesis of retinal ganglion cell phospholipids is under control of an endogenous circadian clock: Daily variations in phospholipid‐synthesizing enzyme activities

Garbarino-Pico¹,

Carpentieri²,

Castagnet³

et al. 2004

J of Neuroscience Research

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Retinal ganglion cells (RGCs) are major components of the vertebrate circadian system. They send information to the brain, synchronizing the entire organism to the light-dark cycles. We recently reported that chicken RGCs display daily variations in the biosynthesis of glycerophospholipids in constant darkness (DD). It was unclear whether this rhythmicity was driven by this population itself or by other retinal cells. Here we show that RGCs present circadian oscillations in the labeling of [32P]phospholipids both in vivo in constant light (LL) and in cultures of immunopurified embryonic cells. In vivo, there was greater [32P]orthophosphate incorporation into total phospholipids during the subjective day. Phosphatidylinositol (PI) was the most 32P-labeled lipid at all times examined, displaying maximal levels during the subjective day and dusk. In addition, a significant daily variation was found in the activity of distinct enzymes of the pathway of phospholipid biosynthesis and degradation, such as lysophospholipid acyltransferases (AT II), phosphatidate phosphohydrolase (PAP), and diacylglycerol lipase (DGL) in cell preparations obtained in DD, exhibiting differential but coordinated temporal profiles. Furthermore, cultures of immunopurified RGCs synchronized by medium exchange displayed a circadian fluctuation in the phospholipid labeling. The results demonstrate that chicken RGCs contain circadian oscillators capable of generating metabolic oscillations in the biosynthesis of phospholipids autonomously.

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Effect of Light on Phosphatidate Phosphohydrolase Activity of Retina Rod Outer Segments: The Role of Transducin

Cited by 12 publications

References 58 publications

Lipid second messengers and related enzymes in vertebrate rod outer segments

Lipid second messengers and related enzymes in vertebrate rod outer segments

Involvement of Lysophosphatidic Acid, Sphingosine 1-Phosphate and Ceramide 1-Phosphate in the Metabolization of Phosphatidic Acid by Lipid Phosphate Phosphatases in Bovine Rod Outer Segments

Synthesis of retinal ganglion cell phospholipids is under control of an endogenous circadian clock: Daily variations in phospholipid‐synthesizing enzyme activities

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