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Zingg JM, Stamatiou C, Montalto G, Daunert S. Modulation of CD36-mediated lipid accumulation and senescence by vitamin E analogs in monocytes and macrophages. Biofactors 2022; 48:665-682. [PMID: 35084073 DOI: 10.1002/biof.1821] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Accepted: 12/14/2021] [Indexed: 01/10/2023]
Abstract
The CD36/FAT scavenger receptor/fatty acids transporter regulates cellular lipid accumulation important for inflammation, atherosclerosis, lipotoxicity, and initiation of cellular senescence. Here we compared the regulatory effects of the vitamin E analogs alpha-tocopherol (αT), alpha-tocopheryl phosphate (αTP), and αTP/βCD (a nanocarrier complex between αTP and β-cyclodextrin [βCD]) and investigated their regulatory effects on lipid accumulation, phagocytosis, and senescence in THP-1 monocytes and macrophages. Both, αTP and αTP/βCD inhibited CD36 surface exposition stronger than αT leading to more pronounced CD36-mediated events such as inhibition of DiI-labeled oxLDL uptake, phagocytosis of fluorescent Staphylococcus aureus bioparticles, and cell proliferation. When compared to βCD, the complex of αTP/βCD extracted cholesterol from cellular membranes with higher efficiency and was associated with the delivery of αTP to the cells. Interestingly, both, αTP and more so αTP/βCD inhibited lysosomal senescence-associated beta-galactosidase (SA-β-gal) activity and increased lysosomal pH, suggesting CD36-mediated uptake into the endo-lysosomal phagocytic compartment. Accordingly, the observed pH increase was more pronounced with αTP/βCD in macrophages whereas no significant increase occurred with αT, alpha-tocopheryl acetate (αTA) or βCD. In contrast to αT and αTA, the αTP molecule is di-anionic at neutral pH, but upon moving into the acidic endo-lysosomal compartment becomes protonated and thus is acting as a base. Moreover, it is expected to be retained in lysosomes since it still carries one negative charge, similar to lysosomotropic drugs. Thus, treatment with αTP or αTP/βCD and/or inhibition of conversion of αTP to αT as it occurs in aged cells may counteract CD36-mediated overlapping inflammatory, senescent, and atherosclerotic events.
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Affiliation(s)
- Jean-Marc Zingg
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, Florida, USA
- Dr. JT Macdonald Foundation Biomedical Nanotechnology Institute, University of Miami, Miami, Florida, USA
| | - Christina Stamatiou
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, Florida, USA
- Dr. JT Macdonald Foundation Biomedical Nanotechnology Institute, University of Miami, Miami, Florida, USA
| | - Giulia Montalto
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, Florida, USA
- Section of General Pathology, Department of Experimental Medicine, University of Genoa, Genoa, Italy
| | - Sylvia Daunert
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, Florida, USA
- Dr. JT Macdonald Foundation Biomedical Nanotechnology Institute, University of Miami, Miami, Florida, USA
- University of Miami Clinical and Translational Science Institute, University of Miami, Miami, Florida, USA
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Zhao H. What do we learn from enzyme behaviors in organic solvents? - Structural functionalization of ionic liquids for enzyme activation and stabilization. Biotechnol Adv 2020; 45:107638. [PMID: 33002582 DOI: 10.1016/j.biotechadv.2020.107638] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 09/05/2020] [Accepted: 09/25/2020] [Indexed: 12/16/2022]
Abstract
Enzyme activity in nonaqueous media (e.g. conventional organic solvents) is typically lower than in water by several orders of magnitude. There is a rising interest of developing new nonaqueous solvent systems that are more "water-like" and more biocompatible. Therefore, we need to learn from the current state of nonaqueous biocatalysis to overcome its bottleneck and provide guidance for new solvent design. This review firstly focuses on the discussion of how organic solvent properties (such as polarity and hydrophobicity) influence the enzyme activity and stability, and how these properties impact the enzyme's conformation and dynamics. While hydrophobic organic solvents usually lead to the maintenance of enzyme activity, solvents carrying functional groups like hydroxys and ethers (including crown ethers and cyclodextrins) can lead to enzyme activation. Ionic liquids (ILs) are designable solvents that can conveniently incorporate these functional groups. Therefore, we systematically survey these ether- and/or hydroxy-functionalized ILs, and find most of them are highly compatible with enzymes leading to high activity and stability. In particular, ILs carrying both ether and tert-alcohol groups are among the most enzyme-activating solvents. Future direction is to learn from enzyme behaviors in both water and nonaqueous media to design biocompatible "water-like" solvents.
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Affiliation(s)
- Hua Zhao
- Department of Chemistry and Biochemistry, University of Northern Colorado, Greeley, CO 80639, United States.
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Kf de Campos M, Schaaf G. The regulation of cell polarity by lipid transfer proteins of the SEC14 family. CURRENT OPINION IN PLANT BIOLOGY 2017; 40:158-168. [PMID: 29017091 DOI: 10.1016/j.pbi.2017.09.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Revised: 09/07/2017] [Accepted: 09/11/2017] [Indexed: 06/07/2023]
Abstract
SEC14 lipid transfer proteins are important regulators of phospholipid metabolism. Structural, genetic and cell biological studies in yeast suggest that they help phosphatidylinositol (PtdIns)/phosphoinositide (PIP) kinases to overcome their intrinsic inefficiency to recognize membrane-embedded substrate, thereby playing a key role in PIP homeostasis. Genomes of higher plants encode a high number and diversity of SEC14 proteins, often in combination with other domains. The Arabidopsis SEC14-Nlj16 protein AtSFH1, an important regulator of root hair development, plays an important role in the establishment of PIP microdomains. Key to this mechanism is a highly specific interaction of the Nlj16 domain with PtdIns(4,5)P2 and an interaction-triggered oligomerization of the protein. Nlj16/PtdIns(4,5)P2 interaction depends on a polybasic motif similar to those identified in other regulatory proteins.
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Affiliation(s)
- Marília Kf de Campos
- Institute of Crop Science and Resource Conservation, Department of Plant Nutrition, University of Bonn, Karlrobert-Kreiten-Strasse 13, 53115 Bonn, Germany.
| | - Gabriel Schaaf
- Institute of Crop Science and Resource Conservation, Department of Plant Nutrition, University of Bonn, Karlrobert-Kreiten-Strasse 13, 53115 Bonn, Germany.
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Kilbride P, Woodward HJ, Tan KB, Thanh NTK, Chu KME, Minogue S, Waugh MG. Modeling the effects of cyclodextrin on intracellular membrane vesicles from Cos-7 cells prepared by sonication and carbonate treatment. PeerJ 2015; 3:e1351. [PMID: 26528413 PMCID: PMC4627923 DOI: 10.7717/peerj.1351] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 10/05/2015] [Indexed: 01/24/2023] Open
Abstract
Cholesterol has important functions in the organization of membrane structure and this may be mediated via the formation of cholesterol-rich, liquid-ordered membrane microdomains often referred to as lipid rafts. Methyl-beta-cyclodextrin (cyclodextrin) is commonly used in cell biology studies to extract cholesterol and therefore disrupt lipid rafts. However, in this study we reassessed this experimental strategy and investigated the effects of cyclodextrin on the physical properties of sonicated and carbonate-treated intracellular membrane vesicles isolated from Cos-7 fibroblasts. We treated these membranes, which mainly originate from the trans-Golgi network and endosomes, with cyclodextrin and measured the effects on their equilibrium buoyant density, protein content, represented by the palmitoylated protein phosphatidylinositol 4-kinase type IIα, and cholesterol. Despite the reduction in mass stemming from cholesterol removal, the vesicles became denser, indicating a possible large volumetric decrease, and this was confirmed by measurements of hydrodynamic vesicle size. Subsequent mathematical analyses demonstrated that only half of this change in membrane size was attributable to cholesterol loss. Hence, the non-selective desorption properties of cyclodextrin are also involved in membrane size and density changes. These findings may have implications for preceding studies that interpreted cyclodextrin-induced changes to membrane biochemistry in the context of lipid raft disruption without taking into account our finding that cyclodextrin treatment also reduces membrane size.
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Affiliation(s)
- Peter Kilbride
- UCL Institute for Liver & Digestive Health, University College London , London , United Kingdom
| | - Holly J Woodward
- UCL Institute for Liver & Digestive Health, University College London , London , United Kingdom
| | - Kuan Boone Tan
- Biophysics Group, Department of Physics & Astronomy, University College London , London , United Kingdom
| | - Nguyễn T K Thanh
- Biophysics Group, Department of Physics & Astronomy, University College London , London , United Kingdom
| | - K M Emily Chu
- UCL Institute for Liver & Digestive Health, University College London , London , United Kingdom
| | - Shane Minogue
- UCL Institute for Liver & Digestive Health, University College London , London , United Kingdom
| | - Mark G Waugh
- UCL Institute for Liver & Digestive Health, University College London , London , United Kingdom
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Im YJ, Smith CM, Phillippy BQ, Strand D, Kramer DM, Grunden AM, Boss WF. Increasing Phosphatidylinositol (4,5)-Bisphosphate Biosynthesis Affects Basal Signaling and Chloroplast Metabolism in Arabidopsis thaliana. PLANTS (BASEL, SWITZERLAND) 2014; 3:27-57. [PMID: 27135490 PMCID: PMC4844314 DOI: 10.3390/plants3010027] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 12/18/2013] [Accepted: 12/20/2013] [Indexed: 01/26/2023]
Abstract
One challenge in studying the second messenger inositol(1,4,5)-trisphosphate (InsP₃) is that it is present in very low amounts and increases only transiently in response to stimuli. To identify events downstream of InsP₃, we generated transgenic plants constitutively expressing the high specific activity, human phosphatidylinositol 4-phosphate 5-kinase Iα (HsPIPKIα). PIP5K is the enzyme that synthesizes phosphatidylinositol (4,5)-bisphosphate (PtdIns(4,5)P₂); this reaction is flux limiting in InsP₃ biosynthesis in plants. Plasma membranes from transgenic Arabidopsis expressing HsPIPKIα had 2-3 fold higher PIP5K specific activity, and basal InsP₃ levels in seedlings and leaves were >2-fold higher than wild type. Although there was no significant difference in photosynthetic electron transport, HsPIPKIα plants had significantly higher starch (2-4 fold) and 20% higher anthocyanin compared to controls. Starch content was higher both during the day and at the end of dark period. In addition, transcripts of genes involved in starch metabolism such as SEX1 (glucan water dikinase) and SEX4 (phosphoglucan phosphatase), DBE (debranching enzyme), MEX1 (maltose transporter), APL3 (ADP-glucose pyrophosphorylase) and glucose-6-phosphate transporter (Glc6PT) were up-regulated in the HsPIPKIα plants. Our results reveal that increasing the phosphoinositide (PI) pathway affects chloroplast carbon metabolism and suggest that InsP₃ is one component of an inter-organelle signaling network regulating chloroplast metabolism.
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Affiliation(s)
- Yang Ju Im
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA.
| | - Caroline M Smith
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA.
| | - Brian Q Phillippy
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA.
| | - Deserah Strand
- DOE-Plant Research Laboratory, Michigan State University, East Lansing, MI 48824, USA.
| | - David M Kramer
- DOE-Plant Research Laboratory, Michigan State University, East Lansing, MI 48824, USA.
| | - Amy M Grunden
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA.
| | - Wendy F Boss
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA.
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Im YJ, Brglez I, Dieck C, Perera IY, Boss WF. Phosphatidylinositol 4-kinase and phosphatidylinositol 4-phosphate 5-kinase assays. Methods Mol Biol 2013; 1009:163-74. [PMID: 23681532 DOI: 10.1007/978-1-62703-401-2_15] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2023]
Abstract
Inositol lipid kinases are perhaps the easiest and most straightforward enzymes in the phosphoinositide pathway to analyze. In addition to monitoring lipid kinase-specific activity, lipid kinase assays can be used to quantify the inositol lipids present in isolated membranes (Jones et al., Methods Mol Biol 462:75-88, 2009). The lipid kinase assays are based on the fact that the more negatively charged phosphorylated lipid products are readily separated from their lipid substrates by thin layer chromatography. We have summarized our current protocols and identified important considerations for working with inositol lipids including different methods for substrate delivery when using recombinant proteins.
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Affiliation(s)
- Yang Ju Im
- Department of Plant Biology, North Carolina State University, Raleigh, NC, USA
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Davis AJ, Im YJ, Dubin JS, Tomer KB, Boss WF. Arabidopsis phosphatidylinositol phosphate kinase 1 binds F-actin and recruits phosphatidylinositol 4-kinase beta1 to the actin cytoskeleton. J Biol Chem 2007; 282:14121-31. [PMID: 17379598 DOI: 10.1074/jbc.m611728200] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The actin cytoskeleton can be influenced by phospholipids and lipid-modifying enzymes. In animals the phosphatidylinositol phosphate kinases (PIPKs) are associated with the cytoskeleton through a scaffold of proteins; however, in plants such an interaction was not clear. Our approach was to determine which of the plant PIPKs interact with actin and determine whether the PIPK-actin interaction is direct. Our results indicate that AtPIPK1 interacts directly with actin and that the binding is mediated through a predicted linker region in the lipid kinase. AtPIPK1 also recruits AtPI4Kbeta1 to the cytoskeleton. Recruitment of AtPI4Kbeta1 to F-actin was dependent on the C-terminal catalytic domain of phosphatidylinositol-4-phosphate 5-kinase but did not require the presence of the N-terminal 251 amino acids, which includes 7 putative membrane occupation and recognition nexus motifs. In vivo studies confirm the interaction of plant lipid kinases with the cytoskeleton and suggest a role for actin in targeting PIPKs to the membrane.
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Affiliation(s)
- Amanda J Davis
- Plant Biology, North Carolina State University, Raleigh, NC 27695, USA
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Im YJ, Davis AJ, Perera IY, Johannes E, Allen NS, Boss WF. The N-terminal membrane occupation and recognition nexus domain of Arabidopsis phosphatidylinositol phosphate kinase 1 regulates enzyme activity. J Biol Chem 2007; 282:5443-52. [PMID: 17197438 DOI: 10.1074/jbc.m611342200] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The type I B family of phosphatidylinositol phosphate kinases (PIPKs) contain a characteristic region of Membrane Occupation and Recognition Nexus (MORN) motifs at the N terminus. These MORN motifs are not found in PIPKs from other eukaryotes. To understand the impact of the additional N-terminal domain on protein function and subcellular distribution, we expressed truncated and full-length versions of AtPIPK1, one member of this family of PIPKs, in Escherichia coli and in tobacco cells grown in suspension culture. Deletion of the N-terminal MORN domain (amino acids 1-251) of AtPIPK1 increased the specific activity of the remaining C-terminal peptide (DeltaMORN) >4-fold and eliminated activation by phosphatidic acid (PtdOH). PtdOH activation could also be eliminated by mutating Pro(396) to Ala (P396A) in the predicted linker region between the MORN and the kinase homology domains. AtPIPK1 is product-activated and the MORN domain binds PtdIns(4,5)P(2). Adding back the MORN peptide to DeltaMORN or to the PtdOH-activated full-length protein increased activity approximately 2-fold. Furthermore, expressing the MORN domain in vivo increased the plasma membrane PtdInsP kinase activity. When cells were exposed to hyperosmotic stress, the MORN peptide redistributed from the plasma membrane to a lower phase or endomembrane fraction. In addition, endogenous PtdInsP kinase activity increased in the endomembrane fraction of hyperosmotically stressed cells. We conclude that the MORN peptide can regulate both the function and distribution of the enzyme in a manner that is sensitive to the lipid environment.
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Affiliation(s)
- Yang Ju Im
- Plant Biology, North Carolina State University, Raleigh, North Carolina 27695-7649, USA
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Boss WF, Davis AJ, Im YJ, Galvão RM, Perera IY. Phosphoinositide metabolism: towards an understanding of subcellular signaling. Subcell Biochem 2006; 39:181-205. [PMID: 17121276 DOI: 10.1007/0-387-27600-9_8] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Affiliation(s)
- Wendy F Boss
- Department of Plant Biology, North Carolina State University, Raleigh, NC 27695-7612, USA
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Kim SH, Zhang J, Jiang Y, Zhou HM, Yan YB. Assisting the reactivation of guanidine hydrochloride-denatured aminoacylase by hydroxypropyl cyclodextrins. Biophys J 2006; 91:686-93. [PMID: 16632505 PMCID: PMC1483089 DOI: 10.1529/biophysj.106.081968] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2006] [Accepted: 04/06/2006] [Indexed: 11/18/2022] Open
Abstract
Cyclodextrin is a water-soluble circular oligosaccharide with a cylinder shape characterized by exterior hydrophilic rims and an interior hydrophobic cavity, which makes it an ideal additive to prevent proteins from aggregating during refolding. In this research, three hydroxypropyl cyclodextrins (HPCDs), HP-alpha-, beta-, and gamma-CD, were used to investigate the molecular mechanism of their effects on assisting aminoacylase refolding. The aggregation and reactivation experiments suggested that at moderate concentrations, HPCDs could suppress aggregation and assist aminoacylase refolding in a concentration-dependent manner, and HP-beta-CD was the most efficient of the three HPCDs. Low concentrations of HP-alpha-CD and high concentrations of HP-gamma-CD promoted off-pathway aggregation. Spectroscopic studies indicated that the hydrophobic exposure of the unstructured species in the refolded solutions was gradually reduced by the three HPCDs with the efficiency HP-beta-CD > HP-gamma-CD > HP-alpha-CD. Furthermore, the fast phase of aminoacylase reactivation was slowed down by the addition of 75 mM HP-beta- and gamma-CD, but no significant effect was observed for HP-alpha-CD. The dissimilarity in the effects of the three HPCDs suggested that the internal cavity size played a crucial role in their antiaggregation ability. Further analysis suggested that the observations might be much more complicated than expected because of the various types of interactions between cyclodextrins and proteins in addition to their ability to bind to protein aromatic residues.
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Affiliation(s)
- Sung-Hye Kim
- Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing 100084, Peoples Republic of China
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Perera IY, Davis AJ, Galanopoulou D, Im YJ, Boss WF. Characterization and comparative analysis of Arabidopsis phosphatidylinositol phosphate 5-kinase 10 reveals differences in Arabidopsis and human phosphatidylinositol phosphate kinases. FEBS Lett 2005; 579:3427-32. [PMID: 15949803 DOI: 10.1016/j.febslet.2005.05.018] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2005] [Revised: 05/04/2005] [Accepted: 05/05/2005] [Indexed: 11/17/2022]
Abstract
Arabidopsis phosphatidylinositol phosphate (PtdInsP) kinase 10 (AtPIPK10; At4g01190) is shown to be a functional enzyme of the subfamily A, type I AtPtdInsP kinases. It is biochemically distinct from AtPIPK1 (At1g21980), the only other previously characterized AtPtdInsP kinase which is of the B subfamily. AtPIPK10 has the same K(m), but a 10-fold lower V(max) than AtPIPK1 and it is insensitive to phosphatidic acid. AtPIPK10 transcript is most abundant in inflorescence stalks and flowers, whereas AtPIPK1 transcript is present in all tissues. Comparative analysis of recombinant AtPIPK10 and AtPIPK1 with recombinant HsPIPKIalpha reveals that the Arabidopsis enzymes have roughly 200- and 20-fold lower V(max)/K(m), respectively. These data reveal one explanation for the longstanding mystery of the relatively low phosphatidylinositol-(4,5)-bisphosphate:phosphatidylinositol-4-phosphate ratio in terrestrial plants.
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Affiliation(s)
- Imara Y Perera
- Botany Department, North Carolina State University, Raleigh, NC 27695-7612, USA.
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