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Hoshino F, Nakayama M, Furuta M, Murakami C, Kato A, Sakane F. Phosphatidylinositol 4,5-bisphosphate-specific phospholipase C β1 selectively binds dipalmitoyl and distearoyl phosphatidic acids via Lys946 and Lys951. Lipids 2022; 57:289-302. [PMID: 36054018 DOI: 10.1002/lipd.12356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 07/31/2022] [Accepted: 08/15/2022] [Indexed: 11/09/2022]
Abstract
Phospholipase C (PLC) β1 hydrolyzes 1-stearoyl-2-arachidonoyl (18:0/20:4)-phosphatidylinositol (PtdIns) 4,5-bisphosphate to produce diacylglycerol, which is converted to phosphatidic acid (PtdOH), in the PtdIns cycle and plays pivotal roles in intracellular signal transduction. The present study identified PLCβ1 as a PtdOH-binding protein using PtdOH-containing liposomes. Moreover, the comparison of the binding of PLCβ1 to various PtdOH species, including 14:0/14:0-PtdOH, 16:0/16:0-PtdOH, 16:0/18:1-PtdOH, 18:0/18:1-PtdOH, 18:0/18:0-PtdOH, 18:1/18:1-PtdOH, 18:0/20:4-PtdOH, and 18:0/22:6-PtdOH, indicated that the interaction of PLCβ1 with 16:0/16:0-PtdOH was the strongest. The PLCβ1-binding activity of 18:0/18:0-PtdOH was almost the same as the binding activity of 16:0/16:0-PtdOH. Furthermore, the binding of PLCβ1 to 16:0/16:0-PtdOH was substantially stronger than 16:0/16:0-phosphatidylserine, 16:0/16:0/16:0/16:0-cardiolipin, 16:0/16:0-PtdIns, and 18:0/20:4-PtdIns. We revealed that a PLCβ1 mutant whose Lys946 and Lys951 residues were replaced with Glu (PLCβ1-KE) did not interact with 16:0/16:0-PtdOH and failed to localize to the plasma membrane in Neuro-2a cells. Retinoic acid-dependent increase in neurite length and numbers was significantly inhibited in PLCβ1-expressing cells; however, this considerable attenuation was not detected in the cells expressing PLCβ1-KE. Overall, these results strongly suggest that PtdOHs containing only saturated fatty acids, including 16:0/16:0-PtdOH, which are not derived from the PtdIns cycle, selectively bind to PLCβ1 and regulate its function.
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Affiliation(s)
- Fumi Hoshino
- Department of Chemistry, Graduate School of Science, Chiba University, Chiba, Japan
| | - Maika Nakayama
- Department of Chemistry, Graduate School of Science, Chiba University, Chiba, Japan
| | - Masataka Furuta
- Department of Chemistry, Graduate School of Science, Chiba University, Chiba, Japan
| | - Chiaki Murakami
- Department of Chemistry, Graduate School of Science, Chiba University, Chiba, Japan.,Institute for Advanced Academic Research, Chiba University, Chiba, Japan
| | - Ayumu Kato
- Department of Chemistry, Graduate School of Science, Chiba University, Chiba, Japan
| | - Fumio Sakane
- Department of Chemistry, Graduate School of Science, Chiba University, Chiba, Japan
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Ishizaki A, Murakami C, Yamada H, Sakane F. Diacylglycerol Kinase η Activity in Cells Using Protein Myristoylation and Cellular Phosphatidic Acid Sensor. Lipids 2021; 56:449-458. [PMID: 33624314 DOI: 10.1002/lipd.12301] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 02/02/2021] [Accepted: 02/09/2021] [Indexed: 12/26/2022]
Abstract
Diacylglycerol kinase (DGK) phosphorylates diacylglycerol to produce phosphatidic acid (PtdOH) and regulates the balance between two lipid second messengers: diacylglycerol and PtdOH. Several lines of evidence suggest that the η isozyme of DGK is involved in the pathogenesis of bipolar disorder. However, the detailed molecular mechanisms regulating the pathophysiological functions remain unclear. One reason is that it is difficult to detect the cellular activity of DGKη. To overcome this difficulty, we utilized protein myristoylation and a cellular PtdOH sensor, the N-terminal region of α-synuclein (α-Syn-N). Although DGKη expressed in COS-7 cells was broadly distributed in the cytoplasm, myristoylated (Myr)-AcGFP-DGKη and Myr-AcGFP-DGKη-KD (inactive (kinase-dead) mutant) were substantially localized in the plasma membrane. Moreover, DsRed monomer-α-Syn-N significantly colocalized with Myr-AcGFP-DGKη but not Myr-AcGFP-DGKη-KD at the plasma membrane. When COS-7 cells were osmotically shocked, all DGKη constructs were exclusively translocated to osmotic shock-responsive granules (OSRG). DsRed monomer-α-Syn-N markedly colocalized with only Myr-AcGFP-DGKη at OSRG and exhibited a higher signal/background ratio (3.4) than Myr-AcGFP-DGKη at the plasma membrane in unstimulated COS-7 cells (2.5), indicating that α-Syn-N more effectively detects Myr-AcGFP-DGKη activity in OSRG. Therefore, these results demonstrated that the combination of myristoylation and the PtdOH sensor effectively detects DGKη activity in cells and that this method is convenient to examine the molecular functions of DGKη. Moreover, this method will be useful for the development of drugs targeting DGKη. Furthermore, the combination of myristoylation (intensive accumulation in membranes) and α-Syn-N can be applicable to assays for various cytosolic PtdOH-generating enzymes.
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Affiliation(s)
- Ayuka Ishizaki
- Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan
| | - Chiaki Murakami
- Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan
| | - Haruka Yamada
- Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan
| | - Fumio Sakane
- Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan
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Sakai H, Murakami C, Usuki T, Lu Q, Matsumoto KI, Urano T, Sakane F. Diacylglycerol kinase η regulates C2C12 myoblast proliferation through the mTOR signaling pathway. Biochimie 2020; 177:13-24. [PMID: 32791090 DOI: 10.1016/j.biochi.2020.07.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 06/16/2020] [Accepted: 07/27/2020] [Indexed: 02/08/2023]
Abstract
Diacylglycerol kinase (DGK) phosphorylates diacylglycerol to produce phosphatidic acid (PA). The η isozyme of DGK is abundantly expressed in C2C12 myoblasts. However, the role of DGKη in skeletal muscle cells remains unknown. In the present study, we showed that DGKη was downregulated at an early stage of myogenic differentiation. The knockdown of DGKη by siRNAs significantly inhibited C2C12 myoblast proliferation but did not inhibit differentiation. Moreover, the suppression of DGKη expression decreased the expression levels of mammalian target of rapamycin (mTOR), which is a key regulator of cell proliferation, and fatty acid synthase (FASN), which catalyzes the de novo synthesis of fatty acids for cell proliferation and is transcriptionally regulated via mTOR signaling. Furthermore, the knockdown of mTOR or raptor, which is a component of mTOR complex 1 (mTORC1), decreased the amount of FASN. These results indicate that DGKη regulates myoblast proliferation through the mTOR (mTORC1)-FASN pathway. Interestingly, the knockdown of mTOR reduced the expression levels of DGKη, implying mutual regulation between DGKη and mTOR. In DGKη-knockdown myoblasts, C30-C36-PA species, mTOR activators, were decreased, suggesting that the modulation of mTOR activity through these PA species also plays an important role in myoblast proliferation.
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Affiliation(s)
- Hiromichi Sakai
- Department of Biosignaling and Radioisotope Experiment, Interdisciplinary Center for Science Research, Organization for Research and Academic Information, Shimane University, Izumo, Japan.
| | - Chiaki Murakami
- Department of Chemistry, Graduate School of Science, Chiba University, Chiba, Japan
| | - Takako Usuki
- Department of Chemistry, Graduate School of Science, Chiba University, Chiba, Japan
| | - Qiang Lu
- Department of Chemistry, Graduate School of Science, Chiba University, Chiba, Japan
| | - Ken-Ichi Matsumoto
- Department of Biosignaling and Radioisotope Experiment, Interdisciplinary Center for Science Research, Organization for Research and Academic Information, Shimane University, Izumo, Japan
| | - Takeshi Urano
- Department of Biosignaling and Radioisotope Experiment, Interdisciplinary Center for Science Research, Organization for Research and Academic Information, Shimane University, Izumo, Japan; Department of Biochemistry, Shimane University School of Medicine, Izumo, Japan
| | - Fumio Sakane
- Department of Chemistry, Graduate School of Science, Chiba University, Chiba, Japan.
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Cellular phosphatidic acid sensor, α-synuclein N-terminal domain, detects endogenous phosphatidic acid in macrophagic phagosomes and neuronal growth cones. Biochem Biophys Rep 2020; 22:100769. [PMID: 32490215 PMCID: PMC7261706 DOI: 10.1016/j.bbrep.2020.100769] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 05/05/2020] [Indexed: 11/22/2022] Open
Abstract
Phosphatidic acid (PA) is the simplest phospholipid and is involved in the regulation of various cellular events. Recently, we developed a new PA sensor, the N-terminal region of α-synuclein (α-Syn-N). However, whether α-Syn-N can sense physiologically produced, endogenous PA remains unclear. We first established an inactive PA sensor (α-Syn-N-KQ) as a negative control by replacing all eleven lysine residues with glutamine residues. Using confocal microscopy, we next verified that α-Syn-N, but not α-Syn-N-KQ, detected PA in macrophagic phagosomes in which PA is known to be enriched, further indicating that α-Syn-N can be used as a reliable PA sensor in cells. Finally, because PA generated during neuronal differentiation is critical for neurite outgrowth, we investigated the subcellular distribution of PA using α-Syn-N. We found that α-Syn-N, but not α-Syn-N-KQ, accumulated at the peripheral regions (close to the plasma membrane) of neuronal growth cones. Experiments using a phospholipase D (PLD) inhibitor strongly suggested that PA in the peripheral regions of the growth cone was primarily produced by PLD. Our findings provide a reliable sensor of endogenous PA and novel insights into the distribution of PA during neuronal differentiation.
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Key Words
- DGK, diacylglycerol kinase
- DMEM, Dulbecco's modified Eagle's medium
- Diacylglycerol kinase
- F-actin, filamentous actin
- FIPI, 5-fluoro-2-indolyl deschlorohalopemide
- Growth cone
- LPA, lysophosphatidic acid
- LPAAT, LPA acyltransferase
- Lipid sensor
- Myr, myristoylated
- PA, phosphatidic acid
- PABD, phosphatidic acid-binding domain
- PC, phosphatidylcholine
- PLD, phospholipase D
- Phagosome
- Phosphatidic acid
- Phospholipase D
- α-Syn, α-synuclein
- α-Syn-N, N-terminal region of α-Syn
- α-Synuclein
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Palmitic acid- and/or palmitoleic acid-containing phosphatidic acids are generated by diacylglycerol kinase α in starved Jurkat T cells. Biochem Biophys Res Commun 2020; 525:1054-1060. [DOI: 10.1016/j.bbrc.2020.02.162] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Accepted: 02/26/2020] [Indexed: 12/11/2022]
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Lu Q, Murakami C, Murakami Y, Hoshino F, Asami M, Usuki T, Sakai H, Sakane F. 1‐Stearoyl‐2‐docosahexaenoyl‐phosphatidic acid interacts with and activates Praja‐1, the E3 ubiquitin ligase acting on the serotonin transporter in the brain. FEBS Lett 2020; 594:1787-1796. [DOI: 10.1002/1873-3468.13765] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 02/15/2020] [Accepted: 02/21/2020] [Indexed: 12/28/2022]
Affiliation(s)
- Qiang Lu
- Department of Chemistry Graduate School of Science Chiba University Chiba Japan
| | - Chiaki Murakami
- Department of Chemistry Graduate School of Science Chiba University Chiba Japan
| | - Yuki Murakami
- Department of Chemistry Graduate School of Science Chiba University Chiba Japan
| | - Fumi Hoshino
- Department of Chemistry Graduate School of Science Chiba University Chiba Japan
| | - Maho Asami
- Department of Chemistry Graduate School of Science Chiba University Chiba Japan
| | - Takako Usuki
- Department of Chemistry Graduate School of Science Chiba University Chiba Japan
| | - Hiromichi Sakai
- Department of Biosignaling and Radioisotope Experiment Interdisciplinary Center for Science Research Organization for Research and Academic Information Shimane University Izumo Japan
| | - Fumio Sakane
- Department of Chemistry Graduate School of Science Chiba University Chiba Japan
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Diacylglycerol kinase δ destabilizes serotonin transporter protein through the ubiquitin-proteasome system. Biochim Biophys Acta Mol Cell Biol Lipids 2020; 1865:158608. [DOI: 10.1016/j.bbalip.2019.158608] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 12/13/2019] [Accepted: 12/27/2019] [Indexed: 01/27/2023]
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Murakami C, Hoshino F, Sakai H, Hayashi Y, Yamashita A, Sakane F. Diacylglycerol kinase δ and sphingomyelin synthase-related protein functionally interact via their sterile α motif domains. J Biol Chem 2020; 295:2932-2947. [PMID: 31980461 DOI: 10.1074/jbc.ra119.012369] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 01/23/2020] [Indexed: 12/27/2022] Open
Abstract
The δ isozyme of diacylglycerol kinase (DGKδ) plays critical roles in lipid signaling by converting diacylglycerol (DG) to phosphatidic acid (PA). We previously demonstrated that DGKδ preferably phosphorylates palmitic acid (16:0)- and/or palmitoleic acid (16:1)-containing DG molecular species, but not arachidonic acid (20:4)-containing DG species, which are recognized as DGK substrates derived from phosphatidylinositol turnover, in high glucose-stimulated myoblasts. However, little is known about the origin of these DG molecular species. DGKδ and two DG-generating enzymes, sphingomyelin synthase (SMS) 1 and SMS-related protein (SMSr), contain a sterile α motif domain (SAMD). In this study, we found that SMSr-SAMD, but not SMS1-SAMD, co-immunoprecipitates with DGKδ-SAMD. Full-length DGKδ co-precipitated with full-length SMSr more strongly than with SMS1. However, SAMD-deleted variants of SMSr and DGKδ interacted only weakly with full-length DGKδ and SMSr, respectively. These results strongly suggested that DGKδ interacts with SMSr through their respective SAMDs. To determine the functional outcomes of the relationship between DGKδ and SMSr, we used LC-MS/MS to investigate whether overexpression of DGKδ and/or SMSr in COS-7 cells alters the levels of PA species. We found that SMSr overexpression significantly enhances the production of 16:0- or 16:1-containing PA species such as 14:0/16:0-, 16:0/16:0-, 16:0/18:1-, and/or 16:1/18:1-PA in DGKδ-overexpressing COS-7 cells. Moreover, SMSr enhanced DGKδ activity via their SAMDs in vitro Taken together, these results strongly suggest that SMSr is a candidate DG-providing enzyme upstream of DGKδ and that the two enzymes represent a new pathway independent of phosphatidylinositol turnover.
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Affiliation(s)
- Chiaki Murakami
- Department of Chemistry, Graduate School of Science, Chiba University, Chiba 263-8522, Japan
| | - Fumi Hoshino
- Department of Chemistry, Graduate School of Science, Chiba University, Chiba 263-8522, Japan
| | - Hiromichi Sakai
- Department of Biosignaling and Radioisotope Experiment, Interdisciplinary Center for Science Research, Organization for Research and Academic Information, Shimane University, Izumo 693-8501, Japan
| | - Yasuhiro Hayashi
- Faculty of Pharma Sciences, Teikyo University, Kaga 2-11-1, Itabashi-ku, Tokyo 173-8605, Japan
| | - Atsushi Yamashita
- Faculty of Pharma Sciences, Teikyo University, Kaga 2-11-1, Itabashi-ku, Tokyo 173-8605, Japan
| | - Fumio Sakane
- Department of Chemistry, Graduate School of Science, Chiba University, Chiba 263-8522, Japan.
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