The salt stress-induced LPA response in Chlamydomonas is produced via PLA2 hydrolysis of DGK-generated phosphatidic acid[S]
The unicellular green alga Chlamydomonas has frequently been used as a eukaryotic model system to study intracellular phospholipid signaling pathways in response to environmental stresses. Earlier, we found that hypersalinity induced a rapid increase in the putative lipid second messenger, phosphati...
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Elsevier
2011-11-01
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Series: | Journal of Lipid Research |
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Online Access: | http://www.sciencedirect.com/science/article/pii/S0022227520350914 |
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author | Steven A. Arisz Teun Munnik |
author_facet | Steven A. Arisz Teun Munnik |
author_sort | Steven A. Arisz |
collection | DOAJ |
description | The unicellular green alga Chlamydomonas has frequently been used as a eukaryotic model system to study intracellular phospholipid signaling pathways in response to environmental stresses. Earlier, we found that hypersalinity induced a rapid increase in the putative lipid second messenger, phosphatidic acid (PA), which was suggested to be generated via activation of a phospholipase D (PLD) pathway and the combined action of a phospholipase C/diacylglycerol kinase (PLC/DGK) pathway. Lysophosphatidic acid (LPA) was also increased and was suggested to reflect a phospholipase A2 (PLA2) activity based on pharmacological evidence. The question of PA’s and LPA’s origin is, however, more complicated, especially as both function as precursors in the biosynthesis of phospho- and galactolipids. To address this complexity, a combination of fatty acid-molecular species analysis and in vivo 32P-radiolabeling was performed. Evidence is provided that LPA is formed from a distinct pool of PA characterized by a high α-linolenic acid (18:3n-3) content. This molecular species was highly enriched in the polyphosphoinositide fraction, which is the substrate for PLC to form diacylglycerol. Together with differential 32P-radiolabeling studies and earlier PLD-transphosphatidylation and PLA2-inhibitor assays, the data were consistent with the hypothesis that the salt-induced LPA response is primarily generated through PLA2-mediated hydrolysis of DGK-generated PA and that PLD or de novo synthesis [via endoplasmic reticulum - or plastid-localized routes] is not a major contributor. |
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spelling | doaj.art-bcf03ef326904b02b2d83aa588d81eca2022-12-21T21:48:27ZengElsevierJournal of Lipid Research0022-22752011-11-01521120122020The salt stress-induced LPA response in Chlamydomonas is produced via PLA2 hydrolysis of DGK-generated phosphatidic acid[S]Steven A. Arisz0Teun Munnik1Section Plant Physiology, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The NetherlandsTo whom correspondence should be addressed.; Section Plant Physiology, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The NetherlandsThe unicellular green alga Chlamydomonas has frequently been used as a eukaryotic model system to study intracellular phospholipid signaling pathways in response to environmental stresses. Earlier, we found that hypersalinity induced a rapid increase in the putative lipid second messenger, phosphatidic acid (PA), which was suggested to be generated via activation of a phospholipase D (PLD) pathway and the combined action of a phospholipase C/diacylglycerol kinase (PLC/DGK) pathway. Lysophosphatidic acid (LPA) was also increased and was suggested to reflect a phospholipase A2 (PLA2) activity based on pharmacological evidence. The question of PA’s and LPA’s origin is, however, more complicated, especially as both function as precursors in the biosynthesis of phospho- and galactolipids. To address this complexity, a combination of fatty acid-molecular species analysis and in vivo 32P-radiolabeling was performed. Evidence is provided that LPA is formed from a distinct pool of PA characterized by a high α-linolenic acid (18:3n-3) content. This molecular species was highly enriched in the polyphosphoinositide fraction, which is the substrate for PLC to form diacylglycerol. Together with differential 32P-radiolabeling studies and earlier PLD-transphosphatidylation and PLA2-inhibitor assays, the data were consistent with the hypothesis that the salt-induced LPA response is primarily generated through PLA2-mediated hydrolysis of DGK-generated PA and that PLD or de novo synthesis [via endoplasmic reticulum - or plastid-localized routes] is not a major contributor.http://www.sciencedirect.com/science/article/pii/S0022227520350914diacylglycerollysophosphatidic acidphospholipase A2signal transduction Chlamydomonas32P-radiolabelingα-linolenic acid |
spellingShingle | Steven A. Arisz Teun Munnik The salt stress-induced LPA response in Chlamydomonas is produced via PLA2 hydrolysis of DGK-generated phosphatidic acid[S] Journal of Lipid Research diacylglycerol lysophosphatidic acid phospholipase A2 signal transduction Chlamydomonas 32P-radiolabeling α-linolenic acid |
title | The salt stress-induced LPA response in Chlamydomonas is produced via PLA2 hydrolysis of DGK-generated phosphatidic acid[S] |
title_full | The salt stress-induced LPA response in Chlamydomonas is produced via PLA2 hydrolysis of DGK-generated phosphatidic acid[S] |
title_fullStr | The salt stress-induced LPA response in Chlamydomonas is produced via PLA2 hydrolysis of DGK-generated phosphatidic acid[S] |
title_full_unstemmed | The salt stress-induced LPA response in Chlamydomonas is produced via PLA2 hydrolysis of DGK-generated phosphatidic acid[S] |
title_short | The salt stress-induced LPA response in Chlamydomonas is produced via PLA2 hydrolysis of DGK-generated phosphatidic acid[S] |
title_sort | salt stress induced lpa response in chlamydomonas is produced via pla2 hydrolysis of dgk generated phosphatidic acid s |
topic | diacylglycerol lysophosphatidic acid phospholipase A2 signal transduction Chlamydomonas 32P-radiolabeling α-linolenic acid |
url | http://www.sciencedirect.com/science/article/pii/S0022227520350914 |
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