1
|
DiPasquale M, Marquardt D. Perceiving the functions of vitamin E through neutron and X-ray scattering. Adv Colloid Interface Sci 2024; 330:103189. [PMID: 38824717 DOI: 10.1016/j.cis.2024.103189] [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: 10/08/2023] [Revised: 05/14/2024] [Accepted: 05/17/2024] [Indexed: 06/04/2024]
Abstract
Take your vitamins, or don't? Vitamin E is one of the few lipophilic vitamins in the human diet and is considered an essential nutrient. Over the years it has proven to be a powerful antioxidant and is commercially used as such, but this association is far from linear in physiology. It is increasingly more likely that vitamin E has multiple legitimate biological roles. Here, we review past and current work using neutron and X-ray scattering to elucidate the influence of vitamin E on key features of model membranes that can translate to the biological function(s) of vitamin E. Although progress is being made, the hundred year-old mystery remains unsolved.
Collapse
Affiliation(s)
| | - Drew Marquardt
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario, Canada; Department of Physics, University of Windsor, Windsor, Ontario, Canada.
| |
Collapse
|
2
|
Abstract
The marvel of X-ray crystallography is the beauty and precision of the atomic structures deduced from diffraction patterns. Since these patterns record only amplitudes, phases for the diffracted waves must also be evaluated for systematic structure determination. Thus, we have the phase problem as a central complication, both intellectually for the field and practically so for many analyses. Here, I discuss how we - myself, my laboratory and the diffraction community - have faced the phase problem, considering the evolution of methods for phase evaluation as structural biology developed to the present day. During the explosive growth of macromolecular crystallography, practice in diffraction analysis evolved from a universal reliance on isomorphous replacement to the eventual domination of anomalous diffraction for de novo structure determination. As the Protein Data Bank (PDB) grew and familial relationships among proteins became clear, molecular replacement overtook all other phasing methods; however, experimental phasing remained essential for molecules without obvious precedents, with multi- and single-wavelength anomalous diffraction (MAD and SAD) predominating. While the mathematics-based direct methods had proved to be inadequate for typical macromolecules, they returned to crack substantial selenium substructures in SAD analyses of selenomethionyl proteins. Native SAD, exploiting the intrinsic S and P atoms of biomolecules, has become routine. Selenomethionyl SAD and MAD were the mainstays of structural genomics efforts to populate the PDB with novel proteins. A recent dividend has been paid in the success of PDB-trained artificial intelligence approaches for protein structure prediction. Currently, molecular replacement with AlphaFold models often obviates the need for experimental phase evaluation. For multiple reasons, we are now unfazed by the phase problem. Cryo-EM analysis is an attractive alternative to crystallography for many applications faced by today's structural biologists. It simply finesses the phase problem; however, the principles and procedures of diffraction analysis remain pertinent and are adopted in single-particle cryo-EM studies of biomolecules.
Collapse
Affiliation(s)
- Wayne A. Hendrickson
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| |
Collapse
|
3
|
Montag K, Ivanov R, Bauer P. Role of SEC14-like phosphatidylinositol transfer proteins in membrane identity and dynamics. FRONTIERS IN PLANT SCIENCE 2023; 14:1181031. [PMID: 37255567 PMCID: PMC10225987 DOI: 10.3389/fpls.2023.1181031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 04/05/2023] [Indexed: 06/01/2023]
Abstract
Membrane identity and dynamic processes, that act at membrane sites, provide important cues for regulating transport, signal transduction and communication across membranes. There are still numerous open questions as to how membrane identity changes and the dynamic processes acting at the surface of membranes are regulated in diverse eukaryotes in particular plants and which roles are being played by protein interaction complexes composed of peripheral and integral membrane proteins. One class of peripheral membrane proteins conserved across eukaryotes comprises the SEC14-like phosphatidylinositol transfer proteins (SEC14L-PITPs). These proteins share a SEC14 domain that contributes to membrane identity and fulfills regulatory functions in membrane trafficking by its ability to sense, bind, transport and exchange lipophilic substances between membranes, such as phosphoinositides and diverse other lipophilic substances. SEC14L-PITPs can occur as single-domain SEC14-only proteins in all investigated organisms or with a modular domain structure as multi-domain proteins in animals and streptophytes (comprising charales and land plants). Here, we present an overview on the functional roles of SEC14L-PITPs, with a special focus on the multi-domain SEC14L-PITPs of the SEC14-nodulin and SEC14-GOLD group (PATELLINs, PATLs in plants). This indicates that SEC14L-PITPs play diverse roles from membrane trafficking to organism fitness in plants. We concentrate on the structure of SEC14L-PITPs, their ability to not only bind phospholipids but also other lipophilic ligands, and their ability to regulate complex cellular responses through interacting with proteins at membrane sites.
Collapse
Affiliation(s)
- Karolin Montag
- Institute of Botany, Heinrich Heine University, Düsseldorf, Germany
| | - Rumen Ivanov
- Institute of Botany, Heinrich Heine University, Düsseldorf, Germany
| | - Petra Bauer
- Institute of Botany, Heinrich Heine University, Düsseldorf, Germany
- Center of Excellence on Plant Sciences (CEPLAS), Germany
| |
Collapse
|
4
|
Xue H, Zhang M, Liu J, Wang J, Ren G. Structure-based mechanism and inhibition of cholesteryl ester transfer protein. Curr Atheroscler Rep 2023; 25:155-166. [PMID: 36881278 PMCID: PMC10027838 DOI: 10.1007/s11883-023-01087-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/02/2023] [Indexed: 03/08/2023]
Abstract
PURPOSE OF REVIEW Cholesteryl ester transfer proteins (CETP) regulate plasma cholesterol levels by transferring cholesteryl esters (CEs) among lipoproteins. Lipoprotein cholesterol levels correlate with the risk factors for atherosclerotic cardiovascular disease (ASCVD). This article reviews recent research on CETP structure, lipid transfer mechanism, and its inhibition. RECENT FINDINGS Genetic deficiency in CETP is associated with a low plasma level of low-density lipoprotein cholesterol (LDL-C) and a profoundly elevated plasma level of high-density lipoprotein cholesterol (HDL-C), which correlates with a lower risk of atherosclerotic cardiovascular disease (ASCVD). However, a very high concentration of HDL-C also correlates with increased ASCVD mortality. Considering that the elevated CETP activity is a major determinant of the atherogenic dyslipidemia, i.e., pro-atherogenic reductions in HDL and LDL particle size, inhibition of CETP emerged as a promising pharmacological target during the past two decades. CETP inhibitors, including torcetrapib, dalcetrapib, evacetrapib, anacetrapib and obicetrapib, were designed and evaluated in phase III clinical trials for the treatment of ASCVD or dyslipidemia. Although these inhibitors increase in plasma HDL-C levels and/or reduce LDL-C levels, the poor efficacy against ASCVD ended interest in CETP as an anti-ASCVD target. Nevertheless, interest in CETP and the molecular mechanism by which it inhibits CE transfer among lipoproteins persisted. Insights into the structural-based CETP-lipoprotein interactions can unravel CETP inhibition machinery, which can hopefully guide the design of more effective CETP inhibitors that combat ASCVD. Individual-molecule 3D structures of CETP bound to lipoproteins provide a model for understanding the mechanism by which CETP mediates lipid transfer and which in turn, guide the rational design of new anti-ASCVD therapeutics.
Collapse
Affiliation(s)
- Han Xue
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Beijing National Laboratory for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing, China
| | - Meng Zhang
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Jianfang Liu
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Jianjun Wang
- Beijing National Laboratory for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing, China
| | - Gang Ren
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
| |
Collapse
|
5
|
Hayashi D, Mouchlis VD, Okamoto S, Namba T, Wang L, Li S, Ueda S, Yamanoue M, Tachibana H, Arai H, Ashida H, Dennis EA, Shirai Y. Vitamin E functions by association with a novel binding site on the 67 kDa laminin receptor activating diacylglycerol kinase. J Nutr Biochem 2022; 110:109129. [PMID: 35977663 PMCID: PMC10243646 DOI: 10.1016/j.jnutbio.2022.109129] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 03/27/2022] [Accepted: 07/16/2022] [Indexed: 01/13/2023]
Abstract
It is generally recognized that the main function of α-tocopherol (αToc), which is the most active form of vitamin E, is its antioxidant effect, while non-antioxidant effects have also been reported. We previously found that αToc ameliorates diabetic nephropathy via diacylglycerol kinase alpha (DGKα) activation in vivo, and the activation was not related to the antioxidant effect. However, the underlying mechanism of how αToc activates DGKα have been enigmatic. We report that the membrane-bound 67 kDa laminin receptor (67LR), which has previously been shown to serve as a receptor for epigallocatechin gallate (EGCG), also contains a novel binding site for vitamin E, and its association with Vitamin E mediates DGKα activation by αToc. We employed hydrogen-deuterium exchange mass spectrometry (HDX/MS) and molecular dynamics (MD) simulations to identify the specific binding site of αToc on the 67LR and discovered the conformation of the specific hydrophobic pocket that accommodates αToc. Also, HDX/MS and MD simulations demonstrated the detailed binding of EGCG to a water-exposed hydrophilic site on 67LR, while in contrast αToc binds to a distinct hydrophobic site. We demonstrated that 67LR triggers an important signaling pathway mediating non-antioxidant effects of αToc, such as DGKα activation. This is the first evidence demonstrating a membrane receptor for αToc and one of the underlying mechanisms of a non-antioxidant function for αToc.
Collapse
Affiliation(s)
- Daiki Hayashi
- Department of Applied Chemistry in Bioscience, Graduate School of Agricultural Science, Faculty of Agriculture, Kobe University, Kobe, Japan; Department of Pharmacology, and Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California, USA
| | - Varnavas D Mouchlis
- Department of Pharmacology, and Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California, USA
| | - Seika Okamoto
- Department of Applied Chemistry in Bioscience, Graduate School of Agricultural Science, Faculty of Agriculture, Kobe University, Kobe, Japan
| | - Tomoka Namba
- Department of Applied Chemistry in Bioscience, Graduate School of Agricultural Science, Faculty of Agriculture, Kobe University, Kobe, Japan
| | - Liuqing Wang
- Department of Applied Chemistry in Bioscience, Graduate School of Agricultural Science, Faculty of Agriculture, Kobe University, Kobe, Japan
| | - Sheng Li
- Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Shuji Ueda
- Department of Applied Chemistry in Bioscience, Graduate School of Agricultural Science, Faculty of Agriculture, Kobe University, Kobe, Japan
| | - Minoru Yamanoue
- Department of Applied Chemistry in Bioscience, Graduate School of Agricultural Science, Faculty of Agriculture, Kobe University, Kobe, Japan
| | - Hirofumi Tachibana
- Division of Applied Biological Chemistry, Department of Bioscience and Biotechnology, Faculty of Agriculture, Kyushu University, Fukuoka, Japan
| | - Hiroyuki Arai
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo Japan
| | - Hitoshi Ashida
- Department of Applied Chemistry in Bioscience, Graduate School of Agricultural Science, Faculty of Agriculture, Kobe University, Kobe, Japan
| | - Edward A Dennis
- Department of Pharmacology, and Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California, USA
| | - Yasuhito Shirai
- Department of Applied Chemistry in Bioscience, Graduate School of Agricultural Science, Faculty of Agriculture, Kobe University, Kobe, Japan.
| |
Collapse
|
6
|
Webster RD. Electrochemical and Spectroscopic Characterization of Oxidized Intermediate Forms of Vitamin E. Molecules 2022; 27:molecules27196194. [PMID: 36234726 PMCID: PMC9571374 DOI: 10.3390/molecules27196194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2022] [Revised: 09/12/2022] [Accepted: 09/15/2022] [Indexed: 11/16/2022] Open
Abstract
Vitamin E, a collection of lipophilic phenolic compounds based on chroman-6-ol, has a rich and fascinating oxidative chemistry involving a range of intermediate forms, some of which are proposed to be important in its biological functions. In this review, the available electrochemical and spectroscopic data on these oxidized intermediates are summarized, along with a discussion on how their lifetimes and chemical stability are either typical of similar phenolic and chroman-6-ol derived compounds, or atypical and unique to the specific oxidized isomeric form of vitamin E. The overall electrochemical oxidation mechanism for vitamin E can be summarized as involving the loss of two-electrons and one-proton, although the electron transfer and chemical steps can be controlled to progress along different pathways to prolong the lifetimes of discreet intermediates by modifying the experimental conditions (applied electrochemical potential, aqueous or non-aqueous solvent, and pH). Depending on the environment, the electrochemical reactions can involve single electron transfer (SET), proton-coupled electron transfer (PCET), as well as homogeneous disproportionation and comproportionation steps. The intermediate species produced via chemical or electrochemical oxidation include phenolates, phenol cation radicals, phenoxyl neutral radicals, dications, diamagnetic cations (phenoxeniums) and para–quinone methides. The cation radicals of all the tocopherols are atypically long-lived compared to the cation radicals of other phenols, due to their relatively weak acidity. The diamagnetic cation derived from α–tocopherol is exceptionally long-lived compared to the diamagnetic cations from the other β–, γ– and δ–isomers of vitamin E and compared with other phenoxenium cations derived from phenolic compounds. In contrast, the lifetime of the phenoxyl radical derived from α–tocopherol, which is considered to be critical in biological reactions, is typical for what is expected for a compound with its structural features. Over longer times via hydrolysis reactions, hydroxy para–quinone hemiketals and quinones can be formed from the oxidized intermediates, which can themselves undergo reduction processes to form intermediate anion radicals and dianions. Methods for generating the oxidized intermediates by chemical, photochemical and electrochemical methods are discussed, along with a summary of how the final products vary depending on the method used for oxidation. Since the intermediates mainly only survive in solution, they are most often monitored using UV-vis spectroscopy, FTIR or Raman spectroscopies, and EPR spectroscopy, with the spectroscopic techniques sometimes combined with fast photoinitiated excitation and time-resolved spectroscopy for detection of short-lived species.
Collapse
Affiliation(s)
- Richard D. Webster
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore;
- Environmental Chemistry and Materials Centre, Nanyang Environment & Water Research Institute (NEWRI), Nanyang Technological University, 1 Cleantech Loop, Clean Tech One, Singapore 637141, Singapore
| |
Collapse
|
7
|
Zhang LW, Liu B, Peng DT. Clinical and genetic study of ataxia with vitamin E deficiency: A case report. World J Clin Cases 2022; 10:8271-8276. [PMID: 36159513 PMCID: PMC9403667 DOI: 10.12998/wjcc.v10.i23.8271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 05/23/2022] [Accepted: 07/11/2022] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Ataxia with vitamin E deficiency (AVED) is a type of autosomal recessive cerebellar ataxia. Clinical manifestations include progressive cerebellar ataxia and movement disorders. TTPA gene mutations cause the disease.
CASE SUMMARY We report the case of a 32-year-old woman who presented with progressive cerebellar ataxia, dysarthria, dystonic tremors and a remarkably decreased serum vitamin E concentration. Brain magnetic resonance images showed that her brainstem and cerebellum were within normal limits. Acquired causes of ataxia were excluded. Whole exome sequencing subsequently identified a novel homozygous variant (c.473T>C, p.F158S) of the TPPA gene. Bioinformatic analysis predicted that F185S is harmful to protein function. After supplementing the patient with vitamin E 400 mg three times per day for 2 years, her symptoms remained stable.
CONCLUSION We identified an AVED patient caused by novel mutation in TTPA gene. Our findings widen the known TTPA gene mutation spectrum.
Collapse
Affiliation(s)
- Lin-Wei Zhang
- Department of Neurology, China-Japan Friendship Hospital, Beijing 100029, China
| | - Bing Liu
- Department of Radiology, China-Japan Friendship Hospital, Beijing 100029, China
| | - Dan-Tao Peng
- Department of Neurology, China-Japan Friendship Hospital, Beijing 100029, China
| |
Collapse
|
8
|
Arai H. [Physiological Function and Congenital Deficiency of α-TTP, a Determinant of Vitamin E Transport in the Body -One Portion of the Research for Which the Pharmaceutical Society of Japan Award Was Given]. YAKUGAKU ZASSHI 2022; 142:775-795. [PMID: 35908939 DOI: 10.1248/yakushi.22-00090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This review summarizes one portion of the research for which the author received the Pharmaceutical Society of Japan Award. The complete title of the awarded research is "Pharmacological Studies on Metabolism and Functions of Biomembrane Lipids". Because the awarded research is a very broad study, this review describes the discovery, physiological functions, and congenital defects of α-tocopherol transfer protein (α-TTP), a critical factor in determining the transport of vitamin E in the body, which has been the focus of the author's work throughout his research career.
Collapse
Affiliation(s)
- Hiroyuki Arai
- Graduate School of Pharmaceutical Sciences, The University of Tokyo
| |
Collapse
|
9
|
Kim E, Poudyal RS, Lee K, Yu H, Gi E, Kim HU. Chloroplast-localized PITP7 is essential for plant growth and photosynthetic function in Arabidopsis. PHYSIOLOGIA PLANTARUM 2022; 174:e13760. [PMID: 36004734 PMCID: PMC9546280 DOI: 10.1111/ppl.13760] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 07/21/2022] [Accepted: 08/02/2022] [Indexed: 06/02/2023]
Abstract
Recent studies of chloroplast-localized Sec14-like protein (CPSFL1, also known as phosphatidylinositol transfer protein 7, PITP7) showed that CPSFL1 is necessary for photoautotropic growth and chloroplast vesicle formation in Arabidopsis (Arabidopsis thaliana). Here, we investigated the functional roles of CPSFL1/PITP7 using two A. thaliana mutants carrying a putative null allele (pitp7-1) and a weak allele (pitp7-2), respectively. PITP7 transcripts were undetectable in pitp7-1 and less abundant in pitp7-2 than in the wild-type (WT). The severity of mutant phenotypes, such as plant developmental abnormalities, levels of plastoquinone-9 (PQ-9) and chlorophylls, photosynthetic protein complexes, and photosynthetic performance, were well related to PITP7 transcript levels. The pitp7-1 mutation was seedling lethal and was associated with significantly lower levels of PQ-9 and major photosynthetic proteins. pitp7-2 plants showed greater susceptibility to high-intensity light stress than the WT, attributable to defects in nonphotochemical quenching and photosynthetic electron transport. PITP7 is specifically bound to phosphatidylinositol phosphates (PIPs) in lipid-binding assays in vitro, and the point mutations R82, H125, E162, or K233 reduced the binding affinity of PITP7 to PIPs. Further, constitutive expression of PITP7H125Q or PITP7E162K in pitp7-1 homozygous plants restored autotrophic growth in soil but without fully complementing the mutant phenotypes. Consistent with a previous study, our results demonstrate that PITP7 is essential for plant development, particularly the accumulation of PQ-9 and photosynthetic complexes. We propose a possible role for PITP7 in membrane trafficking of hydrophobic ligands such as PQ-9 and carotenoids through chloroplast vesicle formation or direct binding involving PIPs.
Collapse
Affiliation(s)
- Eun‐Ha Kim
- Department of Agricultural BiotechnologyNational Institute of Agricultural Sciences, Rural Development AdministrationJeonjuRepublic of Korea
| | - Roshan Sharma Poudyal
- Department of Agricultural BiotechnologyNational Institute of Agricultural Sciences, Rural Development AdministrationJeonjuRepublic of Korea
| | - Kyeong‐Ryeol Lee
- Department of Agricultural BiotechnologyNational Institute of Agricultural Sciences, Rural Development AdministrationJeonjuRepublic of Korea
| | - Hami Yu
- Department of Agricultural BiotechnologyNational Institute of Agricultural Sciences, Rural Development AdministrationJeonjuRepublic of Korea
| | - Eunji Gi
- Department of Agricultural BiotechnologyNational Institute of Agricultural Sciences, Rural Development AdministrationJeonjuRepublic of Korea
| | - Hyun Uk Kim
- Department of Bioindustry and Bioresource EngineeringPlant Engineering Research Institute, Sejong UniversitySeoulRepublic of Korea
| |
Collapse
|
10
|
Arai H, Kono N. α-Tocopherol transfer protein (α-TTP). Free Radic Biol Med 2021; 176:162-175. [PMID: 34563650 DOI: 10.1016/j.freeradbiomed.2021.09.021] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 09/01/2021] [Accepted: 09/03/2021] [Indexed: 10/20/2022]
Abstract
α-Tocopherol transfer protein (α-TTP) is so far the only known protein that specifically recognizes α-tocopherol (α-Toc), the most abundant and most biologically active form of vitamin E, in higher animals. α-TTP is highly expressed in the liver where α-TTP selects α-Toc among vitamin E forms taken up via plasma lipoproteins and promotes its secretion to circulating lipoproteins. Thus, α-TTP is a major determinant of plasma α-Toc concentrations. Familial vitamin E deficiency, also called Ataxia with vitamin E deficiency, is caused by mutations in the α-TTP gene. More than 20 different mutations have been found in the α-TTP gene worldwide, among which some missense mutations provided valuable clues to elucidate the molecular mechanisms underlying intracellular α-Toc transport. In hepatocytes, α-TTP catalyzes the vectorial transport of α-Toc from the endocytotic compartment to the plasma membrane (PM) by targeting phosphatidylinositol phosphates (PIPs) such as PI(4,5)P2. By binding PIPs at the PM, α-TTP opens the lid covering the hydrophobic pocket, thus facilitating the release of bound α-Toc to the PM.
Collapse
Affiliation(s)
- Hiroyuki Arai
- Laboratory of Microenvironmental and Metabolic Health Science, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.
| | - Nozomu Kono
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| |
Collapse
|
11
|
Watt AT, Head B, Leonard SW, Tanguay RL, Traber MG. Gene Expression of CRAL_TRIO Family Proteins modulated by Vitamin E Deficiency in Zebrafish (Danio Rerio). J Nutr Biochem 2021; 97:108801. [PMID: 34119630 PMCID: PMC10129037 DOI: 10.1016/j.jnutbio.2021.108801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 04/19/2021] [Accepted: 06/01/2021] [Indexed: 11/15/2022]
Abstract
An evaluation of the impact of vitamin E deficiency on expression of the alpha-tocopherol transfer protein (α-TTP) and related CRAL_TRIO genes was undertaken using livers from adult zebrafish based on the hypothesis that increased lipid peroxidation would modulate gene expression. Zebrafish were fed either a vitamin E sufficient (E+) or deficient (E-) diet for 9 months, then fish were euthanized, and livers were harvested. Livers from the E+ relative to E- fish contained 40-times more α-tocopherol (P <0.0001) and one fourth the malondialdehyde (P = 0.0153). RNA was extracted from E+ and E- livers, then subject to evaluation of gene expression of ttpa and other genes of the CRAL_TRIO family, genes of antioxidant markers, and genes related to lipid metabolism. Ttpa expression was not altered by vitamin E status. However, one member of the CRAL_TRIO family, tyrosine-protein phosphatase non-receptor type 9 gene (ptpn9a), showed a 2.4-fold increase (P = 0.029) in E- relative to E+ livers. Further, we identified that the gene for choline kinase alpha (chka) showed a 3.0-fold increase (P = 0.010) in E- livers. These outcomes are consistent with our previous findings that show vitamin E deficiency increased lipid peroxidation causing increases in phospholipid turnover.
Collapse
Affiliation(s)
- Alexander T Watt
- Linus Pauling Institute, Oregon State University, Corvallis, Oregon; Integrative Biology Program, Oregon State University, Corvallis, Oregon
| | - Brian Head
- Linus Pauling Institute, Oregon State University, Corvallis, Oregon; Molecular and Cell Biology Program
| | - Scott W Leonard
- Linus Pauling Institute, Oregon State University, Corvallis, Oregon
| | - Robyn L Tanguay
- Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, Oregon
| | - Maret G Traber
- Linus Pauling Institute, Oregon State University, Corvallis, Oregon; School of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon.
| |
Collapse
|
12
|
Zulkiflee NS, Awang SA, Ming WX, Kamilan MFW, Mariappan MY, Kit TJ. In Silico Docking of Vitamin E Isomers on Transport Proteins. Curr Comput Aided Drug Des 2020; 16:467-472. [DOI: 10.2174/1573409915666190614113733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 04/30/2019] [Accepted: 05/07/2019] [Indexed: 11/22/2022]
Abstract
Background:
Vitamin E is comprised of α, β, γ and δ-tocopherols (Ts) and α, β, γ and δ-
tocotrienols (T3s). Vitamin E has neuroprotective antioxidant, anti-cancer, and cholesterol-lowering
effects. Intracellular trafficking of these isomers remains largely unknown, except for αT which is
selectively transported by αT transfer protein (αTTP).
Objective:
This study aimed to determine the binding of vitamin E isomers on transport proteins
using in silico docking.
Methods:
Transport proteins were selected using AmiGo Gene Ontology tool based on the same
molecular function annotation as αTTP. Protein structures were obtained from the Protein Data
Bank. Ligands structures were obtained from ZINC database. In silico docking was performed
using SwissDock.
Results and Discussion:
A total of 6 transport proteins were found: SEC14-like protein 2,
glycolipid transfer protein (GLTP), pleckstrin homology domain-containing family A member 8,
collagen type IV alpha-3-binding protein, ceramide-1-phosphate transfer protein and afamin.
Compared with other transport proteins, αTTP had the highest affinities for all isomers except βT3.
Binding order of vitamin E isomers toward αTTP was γT > βT > αT > δT > αT3 > γT3 > δT3 > βT3.
GLTP had a higher affinity for tocotrienols than tocopherols. βT3 bound stronger to GLTP than αTTP.
Conclusion:
αTTP remained as the most preferred transport protein for most of the isomers. The
binding affinity of αT toward αTTP was not the highest than other isomers suggested that other
intracellular trafficking mechanisms of these isomers may exist. GLTP may mediate the intracellular
transport of tocotrienols, especially βT3. Improving the bioavailability of these isomers may enhance
their beneficial effects to human.
Collapse
Affiliation(s)
- Nurul Syeefa Zulkiflee
- Department of Biochemistry, Faculty of Medicine, Universiti Kebangsaan Malaysia, 56000 Cheras, Malaysia
| | - Siti Amilia Awang
- Department of Biochemistry, Faculty of Medicine, Universiti Kebangsaan Malaysia, 56000 Cheras, Malaysia
| | - Woo Xian Ming
- Department of Biochemistry, Faculty of Medicine, Universiti Kebangsaan Malaysia, 56000 Cheras, Malaysia
| | | | - M Yuveneshwari Mariappan
- Department of Biochemistry, Faculty of Medicine, Universiti Kebangsaan Malaysia, 56000 Cheras, Malaysia
| | - Tan Jen Kit
- Department of Biochemistry, Faculty of Medicine, Universiti Kebangsaan Malaysia, 56000 Cheras, Malaysia
| |
Collapse
|
13
|
Chloroplast Sec14-like 1 (CPSFL1) is essential for normal chloroplast development and affects carotenoid accumulation in Chlamydomonas. Proc Natl Acad Sci U S A 2020; 117:12452-12463. [PMID: 32404426 PMCID: PMC7275715 DOI: 10.1073/pnas.1916948117] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Carotenoids are essential molecules in oxygenic photoautotrophs, and they fulfill essential requirements for human and animal nutrition. How carotenoid accumulation is regulated in the chloroplast, a cyanobacterium-derived organelle, remains poorly understood, despite significant advancements in identifying enzymes of the carotenoid biosynthetic pathway. This study identifies a role of chloroplast Sec14-like 1 (CPSFL1), a CRAL-TRIO protein of eukaryotic origin, in modulation of carotenoid biosynthesis and accumulation in the chloroplast. The CPSFL1 protein represents an isoprenoid- and carotenoid-binding protein that associates with membranes through interactions with the phospholipid phosphatidic acid. These findings have implications for understanding carotenoid biosynthesis and optimizing algal carotenoid nutritional quality. Plastid isoprenoid-derived carotenoids serve essential roles in chloroplast development and photosynthesis. Although nearly all enzymes that participate in the biosynthesis of carotenoids in plants have been identified, the complement of auxiliary proteins that regulate synthesis, transport, sequestration, and degradation of these molecules and their isoprenoid precursors have not been fully described. To identify such proteins that are necessary for the optimal functioning of oxygenic photosynthesis, we screened a large collection of nonphotosynthetic (acetate-requiring) DNA insertional mutants of Chlamydomonas reinhardtii and isolated cpsfl1. The cpsfl1 mutant is extremely light-sensitive and susceptible to photoinhibition and photobleaching. The CPSFL1 gene encodes a CRAL-TRIO hydrophobic ligand-binding (Sec14) domain protein. Proteins containing this domain are limited to eukaryotes, but some may have been retargeted to function in organelles of endosymbiotic origin. The cpsfl1 mutant showed decreased accumulation of plastidial isoprenoid-derived pigments, especially carotenoids, and whole-cell focused ion-beam scanning-electron microscopy revealed a deficiency of carotenoid-rich chloroplast structures (e.g., eyespot and plastoglobules). The low carotenoid content resulted from impaired biosynthesis at a step prior to phytoene, the committed precursor to carotenoids. The CPSFL1 protein bound phytoene and β-carotene when expressed in Escherichia coli and phosphatidic acid in vitro. We suggest that CPSFL1 is involved in the regulation of phytoene synthesis and carotenoid transport and thereby modulates carotenoid accumulation in the chloroplast.
Collapse
|
14
|
Hertle AP, García-Cerdán JG, Armbruster U, Shih R, Lee JJ, Wong W, Niyogi KK. A Sec14 domain protein is required for photoautotrophic growth and chloroplast vesicle formation in Arabidopsis thaliana. Proc Natl Acad Sci U S A 2020; 117:9101-9111. [PMID: 32245810 PMCID: PMC7183190 DOI: 10.1073/pnas.1916946117] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
In eukaryotic photosynthetic organisms, the conversion of solar into chemical energy occurs in thylakoid membranes in the chloroplast. How thylakoid membranes are formed and maintained is poorly understood. However, previous observations of vesicles adjacent to the stromal side of the inner envelope membrane of the chloroplast suggest a possible role of membrane transport via vesicle trafficking from the inner envelope to the thylakoids. Here we show that the model plant Arabidopsis thaliana has a chloroplast-localized Sec14-like protein (CPSFL1) that is necessary for photoautotrophic growth and vesicle formation at the inner envelope membrane of the chloroplast. The cpsfl1 mutants are seedling lethal, show a defect in thylakoid structure, and lack chloroplast vesicles. Sec14 domain proteins are found only in eukaryotes and have been well characterized in yeast, where they regulate vesicle budding at the trans-Golgi network. Like the yeast Sec14p, CPSFL1 binds phosphatidylinositol phosphates (PIPs) and phosphatidic acid (PA) and acts as a phosphatidylinositol transfer protein in vitro, and expression of Arabidopsis CPSFL1 can complement the yeast sec14 mutation. CPSFL1 can transfer PIP into PA-rich membrane bilayers in vitro, suggesting that CPSFL1 potentially facilitates vesicle formation by trafficking PA and/or PIP, known regulators of membrane trafficking between organellar subcompartments. These results underscore the role of vesicles in thylakoid biogenesis and/or maintenance. CPSFL1 appears to be an example of a eukaryotic cytosolic protein that has been coopted for a function in the chloroplast, an organelle derived from endosymbiosis of a cyanobacterium.
Collapse
Affiliation(s)
- Alexander P Hertle
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720;
| | - José G García-Cerdán
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720-3102
- Howard Hughes Medical Institute, University of California, Berkeley, CA 94720
| | - Ute Armbruster
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720-3102
| | - Robert Shih
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
| | - Jimmy J Lee
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720-3102
| | - Winnie Wong
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
| | - Krishna K Niyogi
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720;
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720-3102
- Howard Hughes Medical Institute, University of California, Berkeley, CA 94720
| |
Collapse
|
15
|
Muñoz P, Munné-Bosch S. Vitamin E in Plants: Biosynthesis, Transport, and Function. TRENDS IN PLANT SCIENCE 2019; 24:1040-1051. [PMID: 31606282 DOI: 10.1016/j.tplants.2019.08.006] [Citation(s) in RCA: 82] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 08/06/2019] [Accepted: 08/22/2019] [Indexed: 05/21/2023]
Abstract
Vitamin E, which includes both tocopherols and tocotrienols, comprises lipid-soluble antioxidants that modulate lipid peroxidation. Recently, significant advances have been made in our understanding of vitamin E biosynthesis, transport, and function. The phytyl moiety from chlorophyll degradation is used for tocopherol biosynthesis. An α-tocopherol-binding protein (TBP) has been identified in tomato (SlTBP) serving in intraorganellar vitamin E transport in plants. Moreover, α-tocopherol not only scavenges free radicals through flip-flop movements in the lipid bilayer, but may also contribute to fine-tuning the transmission of specific signals outside chloroplasts. Vitamin E, and α-tocopherol in particular, appear to be essential for plant development and help to provide the most suitable response to a number of environmental stresses.
Collapse
Affiliation(s)
- Paula Muñoz
- Department of Evolutionary Biology, Ecology, and Environmental Sciences, University of Barcelona, Faculty of Biology, Av. Diagonal 643, E-08028 Barcelona, Spain
| | - Sergi Munné-Bosch
- Department of Evolutionary Biology, Ecology, and Environmental Sciences, University of Barcelona, Faculty of Biology, Av. Diagonal 643, E-08028 Barcelona, Spain.
| |
Collapse
|
16
|
Utilization of Vitamin E Analogs to Protect Normal Tissues While Enhancing Antitumor Effects. Semin Radiat Oncol 2019; 29:55-61. [PMID: 30573184 DOI: 10.1016/j.semradonc.2018.10.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Despite advances in radiation delivery techniques, side effects of radiation therapy due to radiation exposure of normal tissues are common and can limit the deliverable dose to tumors. Significant interests lie in pharmacologic modifiers that may protect against normal tissue toxicity from cancer treatment while simultaneously enhancing the tumor response to therapy. While no such treatments are available in the clinic, this is an area of active preclinical and clinical research. This review summarizes research studies that provide evidence to indicate that tocotrienols, natural forms of vitamin E, are potent radiation protectors and may also have antitumor effects. Hence, several current clinical trials test tocotrienols as concomitant treatment in cancer therapies.
Collapse
|
17
|
Suzuki H, Kume A, Herbas MS. Potential of Vitamin E Deficiency, Induced by Inhibition of α-Tocopherol Efflux, in Murine Malaria Infection. Int J Mol Sci 2018; 20:ijms20010064. [PMID: 30586912 PMCID: PMC6337606 DOI: 10.3390/ijms20010064] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 12/19/2018] [Accepted: 12/21/2018] [Indexed: 01/01/2023] Open
Abstract
Although epidemiological and experimental studies have suggested beneficial effects of vitamin E deficiency on malaria infection, it has not been clinically applicable for the treatment of malaria owing to the significant content of vitamin E in our daily food. However, since α-tocopherol transfer protein (α-TTP) has been shown to be a determinant of vitamin E level in circulation, manipulation of α-tocopherol levels by α-TTP inhibition was considered as a potential therapeutic strategy for malaria. Knockout studies in mice indicated that inhibition of α-TTP confers resistance against malaria infections in murines, accompanied by oxidative stress-induced DNA damage in the parasite, arising from vitamin E deficiency. Combination therapy with chloroquine and α-TTP inhibition significantly improved the survival rates in murines with malaria. Thus, clinical application of α-tocopherol deficiency could be possible, provided that α-tocopherol concentration in circulation is reduced. Probucol, a recently found drug, induced α-tocopherol deficiency in circulation and was effective against murine malaria. Currently, treatment of malaria relies on the artemisinin-based combination therapy (ACT); however, when mice infected with malarial parasites were treated with probucol and dihydroartemisinin, the beneficial effect of ACT was pronounced. Protective effects of vitamin E deficiency might be extended to manage other parasites in future.
Collapse
Affiliation(s)
- Hiroshi Suzuki
- Research Unit for Functional Genomics, National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Nishi 2-13, Inada, Obihiro 080-8555, Japan.
- The United Graduate School of Veterinary Sciences, Gifu University, Gifu 501-1193, Japan.
| | - Aiko Kume
- Research Unit for Functional Genomics, National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Nishi 2-13, Inada, Obihiro 080-8555, Japan.
| | - Maria Shirely Herbas
- Research Unit for Functional Genomics, National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Nishi 2-13, Inada, Obihiro 080-8555, Japan.
| |
Collapse
|
18
|
Rengaraj D, Truong AD, Hong Y, Pitargue FM, Kim JH, Hong YH, Han JY, Kil DY. Identification and expression analysis of alpha tocopherol transfer protein in chickens fed diets containing different concentrations of alpha-tocopherol. Res Vet Sci 2018; 123:99-110. [PMID: 30599294 DOI: 10.1016/j.rvsc.2018.12.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 12/20/2018] [Accepted: 12/21/2018] [Indexed: 12/27/2022]
Abstract
Among the eight forms of vitamin E, the liver preferentially releases α-tocopherol into the circulation and it is distributed to the non-liver tissues. In the hepatocytes, alpha tocopherol transfer protein (TTPA) specifically recognizes α-tocopherol with 2R-configuration and facilitates its intracellular transfer. The identification and characterization of TTPA expression have not been demonstrated in avian species. Therefore, the objectives of this study were to identify avian TTPAs, to compare the sequence conservation, phylogenetic relationship, protein interactions, and disease associations of chicken TTPA with those of human and vertebrate TTPA, and to characterize the tissue expression of the TTPA gene in chickens fed diets supplemented with different amounts of α-tocopherol. Our results suggest that the chicken TTPA was highly conserved with the human and vertebrate TTPA, and consisted of a cellular retinaldehyde binding protein and TRIO guanine exchange factor (CRAL_TRIO) domain. Feeding diets supplemented with increasing amounts of α-tocopherol (25 IU/Kg, 50 IU/Kg, or 100 IU/Kg) to broiler chickens had no effects on growth performance compared with feeding basal diets containing no supplemental α-tocopherol. The expression of TTPA gene was detected high in the liver of chickens in response to dietary α-tocopherol concentrations, whereas its expression was very low or undetectable in the non-liver tissues. In conclusion, the chicken TTPA protein sequence is highly conserved with other avian and vertebrate TTPA protein sequences. The higher expression of TTPA gene in the chicken liver in response to dietary α-tocopherol concentrations may suggest its crucial role in transporting α-tocopherol in the chicken liver.
Collapse
Affiliation(s)
- Deivendran Rengaraj
- Department of Animal Science and Technology, Chung-Ang University, Anseong-si, Gyeonggi-do 17546, Republic of Korea; Department of Agricultural Biotechnology, and Research Institute of Agriculture and Life Sciences, College of Agriculture and Life Sciences, Seoul National University, Seoul 08826, Republic of Korea
| | - Anh Duc Truong
- Department of Animal Science and Technology, Chung-Ang University, Anseong-si, Gyeonggi-do 17546, Republic of Korea; Department of Biochemistry and Immunology, National Institute of Veterinary Research, 86 Truong Chinh, Dong Da, Hanoi 100000, Viet Nam
| | - Yeojin Hong
- Department of Animal Science and Technology, Chung-Ang University, Anseong-si, Gyeonggi-do 17546, Republic of Korea
| | - Franco Martinez Pitargue
- Department of Animal Science and Technology, Chung-Ang University, Anseong-si, Gyeonggi-do 17546, Republic of Korea
| | - Jong Hyuk Kim
- Department of Animal Science and Technology, Chung-Ang University, Anseong-si, Gyeonggi-do 17546, Republic of Korea
| | - Yeong Ho Hong
- Department of Animal Science and Technology, Chung-Ang University, Anseong-si, Gyeonggi-do 17546, Republic of Korea
| | - Jae Yong Han
- Department of Agricultural Biotechnology, and Research Institute of Agriculture and Life Sciences, College of Agriculture and Life Sciences, Seoul National University, Seoul 08826, Republic of Korea
| | - Dong Yong Kil
- Department of Animal Science and Technology, Chung-Ang University, Anseong-si, Gyeonggi-do 17546, Republic of Korea.
| |
Collapse
|
19
|
Panagabko C, Baptist M, Atkinson J. In vitro lipid transfer assays of phosphatidylinositol transfer proteins provide insight into the in vivo mechanism of ligand transfer. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1861:619-630. [PMID: 30543784 DOI: 10.1016/j.bbamem.2018.12.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 12/06/2018] [Accepted: 12/07/2018] [Indexed: 11/16/2022]
Abstract
Fluorescence resonance energy transfer (FRET) assays and membrane binding determinations were performed using three phosphatidylinositol transfer proteins, including the yeast Sec14 and two mammalian proteins PITPα and PITPβ. These proteins were able to specifically bind the fluorescent phosphatidylcholine analogue NBD-PC ((2-(12-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)dodecanoyl-1-hexadecanoyl-sn-glycero-3-phosphocholine)) and to transfer it to small unilamellar vesicles (SUVs). Rate constants for transfer to vesicles comprising 100% PC were slower for all proteins than when increasing percentages of phosphatidylinositol were incorporated into the same SUVs. The rates of ligand transfer by Sec14 were insensitive to the inclusion of equimolar amounts of another anionic phospholipid phosphatidylserine (PS), but the rates of ligand transfer by both mammalian PITPs were strikingly enhanced by the inclusion of phosphatidic acid (PA) in the receptor SUV. Binding of Sec14 to immobilized bilayers was substantial, while that of PITPα and PITPβ was 3-7 times weaker than Sec14 depending on phospholipid composition. When small proportions of the phosphoinositide PI(4)P were included in receptor SUVs (either with PI or not), Sec14 showed substantially increased rates of NBD-PC pick-up, whereas the PITPs were unaffected. The data are supportive of a role for PITPβ as functional PI transfer protein in vivo, but that Sec14 likely has a more elaborate function.
Collapse
Affiliation(s)
- Candace Panagabko
- Department of Chemistry and Centre for Biotechnology, Brock University, St. Catharines, Ontario L2A 3S1, Canada
| | - Matilda Baptist
- Department of Chemistry and Centre for Biotechnology, Brock University, St. Catharines, Ontario L2A 3S1, Canada
| | - Jeffrey Atkinson
- Department of Chemistry and Centre for Biotechnology, Brock University, St. Catharines, Ontario L2A 3S1, Canada.
| |
Collapse
|
20
|
Pein H, Ville A, Pace S, Temml V, Garscha U, Raasch M, Alsabil K, Viault G, Dinh CP, Guilet D, Troisi F, Neukirch K, König S, Bilancia R, Waltenberger B, Stuppner H, Wallert M, Lorkowski S, Weinigel C, Rummler S, Birringer M, Roviezzo F, Sautebin L, Helesbeux JJ, Séraphin D, Mosig AS, Schuster D, Rossi A, Richomme P, Werz O, Koeberle A. Endogenous metabolites of vitamin E limit inflammation by targeting 5-lipoxygenase. Nat Commun 2018; 9:3834. [PMID: 30237488 PMCID: PMC6148290 DOI: 10.1038/s41467-018-06158-5] [Citation(s) in RCA: 83] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2018] [Accepted: 08/22/2018] [Indexed: 12/19/2022] Open
Abstract
Systemic vitamin E metabolites have been proposed as signaling molecules, but their physiological role is unknown. Here we show, by library screening of potential human vitamin E metabolites, that long-chain ω-carboxylates are potent allosteric inhibitors of 5-lipoxygenase, a key enzyme in the biosynthesis of chemoattractant and vasoactive leukotrienes. 13-((2R)-6-hydroxy-2,5,7,8-tetramethylchroman-2-yl)-2,6,10-trimethyltridecanoic acid (α-T-13'-COOH) can be synthesized from α-tocopherol in a human liver-on-chip, and is detected in human and mouse plasma at concentrations (8-49 nM) that inhibit 5-lipoxygenase in human leukocytes. α-T-13'-COOH accumulates in immune cells and inflamed murine exudates, selectively inhibits the biosynthesis of 5-lipoxygenase-derived lipid mediators in vitro and in vivo, and efficiently suppresses inflammation and bronchial hyper-reactivity in mouse models of peritonitis and asthma. Together, our data suggest that the immune regulatory and anti-inflammatory functions of α-tocopherol depend on its endogenous metabolite α-T-13'-COOH, potentially through inhibiting 5-lipoxygenase in immune cells.
Collapse
Affiliation(s)
- Helmut Pein
- Chair of Pharmaceutical/Medicinal Chemistry, Institute of Pharmacy, Friedrich-Schiller-University Jena, 07743, Jena, Germany
| | - Alexia Ville
- Substances d'Origine Naturelle et Analogues Structuraux, SONAS, SFR4207 QUASAV, UNIV Angers, Université Bretagne Loire, 49070, Beaucouzé, France
| | - Simona Pace
- Chair of Pharmaceutical/Medicinal Chemistry, Institute of Pharmacy, Friedrich-Schiller-University Jena, 07743, Jena, Germany
| | - Veronika Temml
- Institute of Pharmacy/Pharmacognosy and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, 6020, Innsbruck, Austria
| | - Ulrike Garscha
- Chair of Pharmaceutical/Medicinal Chemistry, Institute of Pharmacy, Friedrich-Schiller-University Jena, 07743, Jena, Germany
| | - Martin Raasch
- Institute of Biochemistry II and Center for Sepsis Control and Care, University Hospital Jena, 07743, Jena, Germany
| | - Khaled Alsabil
- Substances d'Origine Naturelle et Analogues Structuraux, SONAS, SFR4207 QUASAV, UNIV Angers, Université Bretagne Loire, 49070, Beaucouzé, France
| | - Guillaume Viault
- Substances d'Origine Naturelle et Analogues Structuraux, SONAS, SFR4207 QUASAV, UNIV Angers, Université Bretagne Loire, 49070, Beaucouzé, France
| | - Chau-Phi Dinh
- Substances d'Origine Naturelle et Analogues Structuraux, SONAS, SFR4207 QUASAV, UNIV Angers, Université Bretagne Loire, 49070, Beaucouzé, France
| | - David Guilet
- Substances d'Origine Naturelle et Analogues Structuraux, SONAS, SFR4207 QUASAV, UNIV Angers, Université Bretagne Loire, 49070, Beaucouzé, France
| | - Fabiana Troisi
- Chair of Pharmaceutical/Medicinal Chemistry, Institute of Pharmacy, Friedrich-Schiller-University Jena, 07743, Jena, Germany
| | - Konstantin Neukirch
- Chair of Pharmaceutical/Medicinal Chemistry, Institute of Pharmacy, Friedrich-Schiller-University Jena, 07743, Jena, Germany
| | - Stefanie König
- Chair of Pharmaceutical/Medicinal Chemistry, Institute of Pharmacy, Friedrich-Schiller-University Jena, 07743, Jena, Germany
| | - Rosella Bilancia
- Department of Pharmacy, School of Medicine, University of Naples Federico II, 80131, Naples, Italy
| | - Birgit Waltenberger
- Institute of Pharmacy/Pharmacognosy and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, 6020, Innsbruck, Austria
| | - Hermann Stuppner
- Institute of Pharmacy/Pharmacognosy and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, 6020, Innsbruck, Austria
| | - Maria Wallert
- Chair of Nutritional Biochemistry and Physiology, Institute of Nutrition, Friedrich-Schiller-University Jena, 07743, Jena, Germany
| | - Stefan Lorkowski
- Chair of Nutritional Biochemistry and Physiology, Institute of Nutrition, Friedrich-Schiller-University Jena, 07743, Jena, Germany.,Competence Cluster of Nutrition and Cardiovascular Health (nutriCARD), Halle, Jena and Leipzig, Jena, 07743, Germany
| | - Christina Weinigel
- Institute of Transfusion Medicine, University Hospital Jena, 07747, Jena, Germany
| | - Silke Rummler
- Institute of Transfusion Medicine, University Hospital Jena, 07747, Jena, Germany
| | - Marc Birringer
- Department of Nutritional, Food and Consumer Sciences, Fulda University of Applied Sciences, 36037, Fulda, Germany
| | - Fiorentina Roviezzo
- Department of Pharmacy, School of Medicine, University of Naples Federico II, 80131, Naples, Italy
| | - Lidia Sautebin
- Department of Pharmacy, School of Medicine, University of Naples Federico II, 80131, Naples, Italy
| | - Jean-Jacques Helesbeux
- Substances d'Origine Naturelle et Analogues Structuraux, SONAS, SFR4207 QUASAV, UNIV Angers, Université Bretagne Loire, 49070, Beaucouzé, France
| | - Denis Séraphin
- Substances d'Origine Naturelle et Analogues Structuraux, SONAS, SFR4207 QUASAV, UNIV Angers, Université Bretagne Loire, 49070, Beaucouzé, France
| | - Alexander S Mosig
- Institute of Biochemistry II and Center for Sepsis Control and Care, University Hospital Jena, 07743, Jena, Germany
| | - Daniela Schuster
- Institute of Pharmacy/Pharmaceutical Chemistry and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, 6020, Innsbruck, Austria.,Department of Pharmaceutical and Medicinal Chemistry, Institute of Pharmacy, Paracelsus Medical University Salzburg, 5020, Salzburg, Austria
| | - Antonietta Rossi
- Department of Pharmacy, School of Medicine, University of Naples Federico II, 80131, Naples, Italy
| | - Pascal Richomme
- Substances d'Origine Naturelle et Analogues Structuraux, SONAS, SFR4207 QUASAV, UNIV Angers, Université Bretagne Loire, 49070, Beaucouzé, France
| | - Oliver Werz
- Chair of Pharmaceutical/Medicinal Chemistry, Institute of Pharmacy, Friedrich-Schiller-University Jena, 07743, Jena, Germany.
| | - Andreas Koeberle
- Chair of Pharmaceutical/Medicinal Chemistry, Institute of Pharmacy, Friedrich-Schiller-University Jena, 07743, Jena, Germany.
| |
Collapse
|
21
|
Hanada K. Lipid transfer proteins rectify inter-organelle flux and accurately deliver lipids at membrane contact sites. J Lipid Res 2018; 59:1341-1366. [PMID: 29884707 PMCID: PMC6071762 DOI: 10.1194/jlr.r085324] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Revised: 05/24/2018] [Indexed: 12/22/2022] Open
Abstract
The endoplasmic reticulum (ER) is the main center for the synthesis of various lipid types in cells, and newly synthesized lipids are delivered from the ER to other organelles. In the past decade, various lipid transfer proteins (LTPs) have been recognized as mediators of lipid transport from the ER to other organelles; inter-organelle transport occurs at membrane contact sites (MCSs) and in a nonvesicular manner. Although the intermembrane transfer reaction catalyzed by LTPs is an equilibrium reaction, various types of newly synthesized lipids are transported unidirectionally in cells. This review provides a brief history of the inter-organelle trafficking of lipids and summarizes the structural and biochemical characteristics of the ceramide transport protein (CERT) as a typical LTP acting at MCSs. In addition, this review compares several LTP-mediated inter-organelle lipid trafficking systems and proposes that LTPs generate unidirectional fluxes of specific lipids between different organelles by indirect coupling with the metabolic reactions that occur in specific organelles. Moreover, the available data also suggest that the major advantage of LTP-mediated lipid transport at MCSs may be the accuracy of delivery. Finally, how cholesterol is enriched in the plasma membrane is discussed from a thermodynamic perspective.
Collapse
Affiliation(s)
- Kentaro Hanada
- Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, Shinjuku-ku, Tokyo 162-8640, Japan
| |
Collapse
|
22
|
Peltzer RM, Kolli HB, Stocker A, Cascella M. Self-Assembly of α-Tocopherol Transfer Protein Nanoparticles: A Patchy Protein Model. J Phys Chem B 2018; 122:7066-7072. [DOI: 10.1021/acs.jpcb.8b05936] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Raphael Mathias Peltzer
- Department of Chemistry, and Hylleraas Centre for Quantum Molecular Sciences, University of Oslo, P.O.
Box 1033, Blindern, 0315 Oslo, Norway
| | - Hima Bindu Kolli
- Department of Chemistry, and Hylleraas Centre for Quantum Molecular Sciences, University of Oslo, P.O.
Box 1033, Blindern, 0315 Oslo, Norway
| | - Achim Stocker
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland
| | - Michele Cascella
- Department of Chemistry, and Hylleraas Centre for Quantum Molecular Sciences, University of Oslo, P.O.
Box 1033, Blindern, 0315 Oslo, Norway
| |
Collapse
|
23
|
Dietary Vitamin E Status Dictates Oxidative Stress Outcomes by Modulating Effects of Fish Oil Supplementation in Alzheimer Disease Model APPswe/PS1dE9 Mice. Mol Neurobiol 2018; 55:9204-9219. [DOI: 10.1007/s12035-018-1060-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Accepted: 04/03/2018] [Indexed: 02/02/2023]
|
24
|
Nukala U, Thakkar S, Krager KJ, Breen PJ, Compadre CM, Aykin-Burns N. Antioxidant Tocols as Radiation Countermeasures (Challenges to be Addressed to Use Tocols as Radiation Countermeasures in Humans). Antioxidants (Basel) 2018; 7:antiox7020033. [PMID: 29473853 PMCID: PMC5836023 DOI: 10.3390/antiox7020033] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 02/19/2018] [Accepted: 02/22/2018] [Indexed: 01/08/2023] Open
Abstract
Radiation countermeasures fall under three categories, radiation protectors, radiation mitigators, and radiation therapeutics. Radiation protectors are agents that are administered before radiation exposure to protect from radiation-induced injuries by numerous mechanisms, including scavenging free radicals that are generated by initial radiochemical events. Radiation mitigators are agents that are administered after the exposure of radiation but before the onset of symptoms by accelerating the recovery and repair from radiation-induced injuries. Whereas radiation therapeutic agents administered after the onset of symptoms act by regenerating the tissues that are injured by radiation. Vitamin E is an antioxidant that neutralizes free radicals generated by radiation exposure by donating H atoms. The vitamin E family consists of eight different vitamers, including four tocopherols and four tocotrienols. Though alpha-tocopherol was extensively studied in the past, tocotrienols have recently gained attention as radiation countermeasures. Despite several studies performed on tocotrienols, there is no clear evidence on the factors that are responsible for their superior radiation protection properties over tocopherols. Their absorption and bioavailability are also not well understood. In this review, we discuss tocopherol’s and tocotrienol’s efficacy as radiation countermeasures and identify the challenges to be addressed to develop them into radiation countermeasures for human use in the event of radiological emergencies.
Collapse
Affiliation(s)
- Ujwani Nukala
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
- Joint Bioinformatics Graduate Program, University of Arkansas at Little Rock, Little Rock, AR 72204, USA.
| | - Shraddha Thakkar
- Division of Bioinformatics and Biostatistics, National Center for Toxicological Research, US Food and Drug Administration, Jefferson, AR 72079, USA.
| | - Kimberly J Krager
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
| | - Philip J Breen
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
- Tocol Pharmaceuticals, LLC, Little Rock, AR 77205, USA.
| | - Cesar M Compadre
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
- Tocol Pharmaceuticals, LLC, Little Rock, AR 77205, USA.
| | - Nukhet Aykin-Burns
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
- Tocol Pharmaceuticals, LLC, Little Rock, AR 77205, USA.
| |
Collapse
|
25
|
Macias-Muñoz A, McCulloch KJ, Briscoe AD. Copy Number Variation and Expression Analysis Reveals a Nonorthologous Pinta Gene Family Member Involved in Butterfly Vision. Genome Biol Evol 2017; 9:3398-3412. [PMID: 29136137 PMCID: PMC5739039 DOI: 10.1093/gbe/evx230] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/08/2017] [Indexed: 02/06/2023] Open
Abstract
Vertebrate (cellular retinaldehyde-binding protein) and Drosophila (prolonged depolarization afterpotential is not apparent [PINTA]) proteins with a CRAL-TRIO domain transport retinal-based chromophores that bind to opsin proteins and are necessary for phototransduction. The CRAL-TRIO domain gene family is composed of genes that encode proteins with a common N-terminal structural domain. Although there is an expansion of this gene family in Lepidoptera, there is no lepidopteran ortholog of pinta. Further, the function of these genes in lepidopterans has not yet been established. Here, we explored the molecular evolution and expression of CRAL-TRIO domain genes in the butterfly Heliconius melpomene in order to identify a member of this gene family as a candidate chromophore transporter. We generated and searched a four tissue transcriptome and searched a reference genome for CRAL-TRIO domain genes. We expanded an insect CRAL-TRIO domain gene phylogeny to include H. melpomene and used 18 genomes from 4 subspecies to assess copy number variation. A transcriptome-wide differential expression analysis comparing four tissue types identified a CRAL-TRIO domain gene, Hme CTD31, upregulated in heads suggesting a potential role in vision for this CRAL-TRIO domain gene. RT-PCR and immunohistochemistry confirmed that Hme CTD31 and its protein product are expressed in the retina, specifically in primary and secondary pigment cells and in tracheal cells. Sequencing of eye protein extracts that fluoresce in the ultraviolet identified Hme CTD31 as a possible chromophore binding protein. Although we found several recent duplications and numerous copy number variants in CRAL-TRIO domain genes, we identified a single copy pinta paralog that likely binds the chromophore in butterflies.
Collapse
Affiliation(s)
- Aide Macias-Muñoz
- Department of Ecology and Evolutionary Biology, University of California, Irvine
| | - Kyle J McCulloch
- Department of Ecology and Evolutionary Biology, University of California, Irvine.,FAS Center for Systems Biology, Harvard University
| | - Adriana D Briscoe
- Department of Ecology and Evolutionary Biology, University of California, Irvine
| |
Collapse
|
26
|
Singh G, Sachdeva R, Rai B, Saini G. Structure and vibrational spectroscopic study of alpha-tocopherol. J Mol Struct 2017. [DOI: 10.1016/j.molstruc.2017.05.037] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|
27
|
Aeschimann W, Staats S, Kammer S, Olieric N, Jeckelmann JM, Fotiadis D, Netscher T, Rimbach G, Cascella M, Stocker A. Self-assembled α-Tocopherol Transfer Protein Nanoparticles Promote Vitamin E Delivery Across an Endothelial Barrier. Sci Rep 2017; 7:4970. [PMID: 28694484 PMCID: PMC5504013 DOI: 10.1038/s41598-017-05148-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Accepted: 05/24/2017] [Indexed: 01/16/2023] Open
Abstract
Vitamin E is one of the most important natural antioxidants, protecting polyunsaturated fatty acids in the membranes of cells. Among different chemical isoforms assimilated from dietary regimes, RRR-α-tocopherol is the only one retained in higher animals. This is possible thanks to α-Tocopherol Transfer Protein (α-TTP), which extracts α-tocopherol from endosomal compartments in liver cells, facilitating its distribution into the body. Here we show that, upon binding to its substrate, α-TTP acquires tendency to aggregation into thermodynamically stable high molecular weight oligomers. Determination of the structure of such aggregates by X-ray crystallography revealed a spheroidal particle formed by 24 protein monomers. Oligomerization is triggered by refolding of the N-terminus. Experiments with cultured cell monolayers demonstrate that the same oligomers are efficiently transported through an endothelial barrier (HUVEC) and not through an epithelial one (Caco-2). Discovery of a human endogenous transport protein with intrinsic capability of crossing endothelial tissues opens to new ways of drug delivery into the brain or other tissues protected by endothelial barriers.
Collapse
Affiliation(s)
- Walter Aeschimann
- University of Bern, Department of Chemistry and Biochemistry, Bern, Switzerland
| | - Stefanie Staats
- University of Kiel, Institute of Human Nutrition and Food Science, Kiel, Germany
| | - Stephan Kammer
- University of Bern, Department of Chemistry and Biochemistry, Bern, Switzerland
| | | | - Jean-Marc Jeckelmann
- University of Bern, Institute of Biochemistry and Molecular Medicine, Bern, Switzerland
| | - Dimitrios Fotiadis
- University of Bern, Institute of Biochemistry and Molecular Medicine, Bern, Switzerland
| | | | - Gerald Rimbach
- University of Kiel, Institute of Human Nutrition and Food Science, Kiel, Germany
| | - Michele Cascella
- University of Oslo, Department of Chemistry and Centre for Theoretical and Computational Chemistry (CTCC), Oslo, Norway.
| | - Achim Stocker
- University of Bern, Department of Chemistry and Biochemistry, Bern, Switzerland.
| |
Collapse
|
28
|
Liu X, Gujarathi S, Zhang X, Shao L, Boerma M, Compadre CM, Crooks PA, Hauer-Jensen M, Zhou D, Zheng G. Synthesis of (2 R,8' S,3' E)-δ-tocodienol, a tocoflexol family member designed to have a superior pharmacokinetic profile compared to δ-tocotrienol. Tetrahedron 2016; 72:4001-4006. [PMID: 27773949 PMCID: PMC5070675 DOI: 10.1016/j.tet.2016.05.028] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
A group of side chain partially saturated tocotrienol analogues, namely tocoflexols, have been previously designed in an effort to improve the pharmacokinetic properties of tocotrienols. (2R,8'S,3'E,11'E)-δ-Tocodienol (1) was predicted to be a high value tocoflexol for further pharmacological evaluation. We now report here an efficient 8-step synthetic route to compound 1 utilizing naturally-occurring δ-tocotrienol as a starting material (24% total yield). The key step in the synthesis is oxidative olefin cleavage of δ-tocotrienol to afford the chroman core of 1 with retention of chirality at the C-2 stereocenter.
Collapse
Affiliation(s)
- Xingui Liu
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, AR 72205, United States
| | - Satheesh Gujarathi
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, AR 72205, United States
| | - Xuan Zhang
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, AR 72205, United States
| | - Lijian Shao
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, AR 72205, United States
| | - Marjan Boerma
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, AR 72205, United States
| | - Cesar M. Compadre
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, AR 72205, United States
| | - Peter A. Crooks
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, AR 72205, United States
| | - Martin Hauer-Jensen
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, AR 72205, United States
| | - Daohong Zhou
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, AR 72205, United States
| | - Guangrong Zheng
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Arkansas for Medical Sciences, Little Rock, AR 72205, United States
| |
Collapse
|
29
|
Abstract
The discovery of vitamin E (α-tocopherol) began in 1922 as a vital component required in reproduction. Today, there are eight naturally occurring vitamin E isoforms, namely α-, β-, γ- and δ-tocopherol and α-, β-, γ- and δ-tocotrienol. Vitamin E is potent antioxidants, capable of neutralizing free radicals directly by donating hydrogen from its chromanol ring. α-Tocopherol is regarded the dominant form in vitamin E as the α-tocopherol transfer protein in the liver binds mainly α-tocopherol, thus preventing its degradation. That contributed to the oversight of tocotrienols and resulted in less than 3% of all vitamin E publications studying tocotrienols. Nevertheless, tocotrienols have been shown to possess superior antioxidant and anti-inflammatory properties over α-tocopherol. In particular, inhibition of 3-hydroxy-3-methylglutaryl-coenzyme A reductase to lower cholesterol, attenuating inflammation via downregulation of transcription factor NF-κB activation, and potent radioprotectant against radiation damage are some properties unique to tocotrienols, not tocopherols. Aside from cancer, vitamin E has also been shown protective in bone, cardiovascular, eye, nephrological and neurological diseases. In light of the different pharmacological properties of tocopherols and tocotrienols, it becomes critical to specify which vitamin E isoform(s) are being studied in any future vitamin E publications. This review provides an update on vitamin E therapeutic potentials, protective effects and modes of action beyond cancer, with comparison of tocopherols against tocotrienols. With the concerted efforts in synthesizing novel vitamin E analogs and clinical pharmacology of vitamin E, it is likely that certain vitamin E isoform(s) will be therapeutic agents against human diseases besides cancer.
Collapse
Affiliation(s)
- Hong Yong Peh
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University Health System, Singapore
| | - W S Daniel Tan
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University Health System, Singapore
| | - Wupeng Liao
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University Health System, Singapore
| | - W S Fred Wong
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University Health System, Singapore; Immunology Program, Life Science Institute, National University of Singapore, Singapore.
| |
Collapse
|
30
|
Smith G, Briscoe AD. Molecular evolution and expression of the CRAL_TRIO protein family in insects. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2015; 62:168-173. [PMID: 25684408 DOI: 10.1016/j.ibmb.2015.02.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Revised: 01/29/2015] [Accepted: 02/03/2015] [Indexed: 06/04/2023]
Abstract
CRAL_TRIO domain proteins are known to bind small lipophilic molecules such as retinal, inositol and Vitamin E and include such gene family members as PINTA, α-tocopherol transfer (ATT) proteins, retinoid binding proteins, and clavesins. In insects, very little is known about either the molecular evolution of this family of proteins or their ligand specificity. Here we characterize insect CRAL_TRIO domain proteins and present the first insect CRAL_TRIO protein phylogeny constructed by performing reciprocal BLAST searches of the reference genomes of Drosophila melanogaster, Anopheles gambiae, Apis mellifera, Tribolium castaneum, Bombyx mori, Manduca sexta and Danaus plexippus. We find several highly conserved amino acid residues in the CRAL_TRIO domain-containing genes across insects and a gene expansion resulting in more than twice as many gene family members in lepidopterans than in other surveyed insect species, but no lepidopteran homolog of the PINTA gene in Drosophila. In addition, we examined the expression pattern of CRAL_TRIO domain genes in Manduca sexta heads using RNA-Seq data. Of the 42 gene family members found in the M. sexta reference genome, we found 30 expressed in the head tissue with similar expression profiles between males and females. Our results suggest this gene family underwent a large expansion in lepidopteran, making the lepidopteran CRAL_TRIO domain family distinct from other holometabolous insect lineages.
Collapse
Affiliation(s)
- Gilbert Smith
- Department of Ecology and Evolutionary Biology, University of California, Irvine, CA 92697, USA.
| | - Adriana D Briscoe
- Department of Ecology and Evolutionary Biology, University of California, Irvine, CA 92697, USA
| |
Collapse
|
31
|
Lamprakis C, Stocker A, Cascella M. Mechanisms of recognition and binding of α-TTP to the plasma membrane by multi-scale molecular dynamics simulations. Front Mol Biosci 2015; 2:36. [PMID: 26191529 PMCID: PMC4487086 DOI: 10.3389/fmolb.2015.00036] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 06/15/2015] [Indexed: 12/12/2022] Open
Abstract
We used multiple sets of simulations both at the atomistic and coarse-grained level of resolution to investigate interaction and binding of α-tochoperol transfer protein (α-TTP) to phosphatidylinositol phosphate lipids (PIPs). Our calculations indicate that enrichment of membranes with such lipids facilitate membrane anchoring. Atomistic models suggest that PIP can be incorporated into the binding cavity of α-TTP and therefore confirm that such protein can work as lipid exchanger between the endosome and the plasma membrane. Comparison of the atomistic models of the α-TTP-PIPs complex with membrane-bound α-TTP revealed different roles for the various basic residues composing the basic patch that is key for the protein/ligand interaction. Such residues are of critical importance as several point mutations at their position lead to severe forms of ataxia with vitamin E deficiency (AVED) phenotypes. Specifically, R221 is main residue responsible for the stabilization of the complex. R68 and R192 exchange strong interactions in the protein or in the membrane complex only, suggesting that the two residues alternate contact formation, thus facilitating lipid flipping from the membrane into the protein cavity during the lipid exchange process. Finally, R59 shows weaker interactions with PIPs anyway with a clear preference for specific phosphorylation positions, hinting a role in early membrane selectivity for the protein. Altogether, our simulations reveal significant aspects at the atomistic scale of interactions of α-TTP with the plasma membrane and with PIP, providing clarifications on the mechanism of intracellular vitamin E trafficking and helping establishing the role of key residue for the functionality of α-TTP.
Collapse
Affiliation(s)
- Christos Lamprakis
- Department of Chemistry and Biochemistry, University of Bern Bern, Switzerland
| | - Achim Stocker
- Department of Chemistry and Biochemistry, University of Bern Bern, Switzerland
| | - Michele Cascella
- Department of Chemistry, Centre for Theoretical and Computational Chemistry, University of Oslo Oslo, Norway
| |
Collapse
|
32
|
Structural insights on cholesterol endosynthesis: Binding of squalene and 2,3-oxidosqualene to supernatant protein factor. J Struct Biol 2015; 190:261-70. [DOI: 10.1016/j.jsb.2015.05.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Revised: 05/08/2015] [Accepted: 05/11/2015] [Indexed: 11/24/2022]
|
33
|
Kono N, Arai H. Intracellular transport of fat-soluble vitamins A and E. Traffic 2014; 16:19-34. [PMID: 25262571 DOI: 10.1111/tra.12231] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Revised: 09/24/2014] [Accepted: 09/25/2014] [Indexed: 12/11/2022]
Abstract
Vitamins are compounds that are essential for the normal growth, reproduction and functioning of the human body. Of the 13 known vitamins, vitamins A, D, E and K are lipophilic compounds and are therefore called fat-soluble vitamins. Because of their lipophilicity, fat-soluble vitamins are solubilized and transported by intracellular carrier proteins to exert their actions and to be metabolized properly. Vitamin A and its derivatives, collectively called retinoids, are solubilized by intracellular retinoid-binding proteins such as cellular retinol-binding protein (CRBP), cellular retinoic acid-binding protein (CRABP) and cellular retinal-binding protein (CRALBP). These proteins act as chaperones that regulate the metabolism, signaling and transport of retinoids. CRALBP-mediated intracellular retinoid transport is essential for vision in human. α-Tocopherol, the main form of vitamin E found in the body, is transported by α-tocopherol transfer protein (α-TTP) in hepatic cells. Defects of α-TTP cause vitamin E deficiency and neurological disorders in humans. Recently, it has been shown that the interaction of α-TTP with phosphoinositides plays a critical role in the intracellular transport of α-tocopherol and is associated with familial vitamin E deficiency. In this review, we summarize the mechanisms and biological significance of the intracellular transport of vitamins A and E.
Collapse
Affiliation(s)
- Nozomu Kono
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, the University of Tokyo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | | |
Collapse
|
34
|
Compadre CM, Singh A, Thakkar S, Zheng G, Breen PJ, Ghosh S, Kiaei M, Boerma M, Varughese KI, Hauer-Jensen M. Molecular dynamics guided design of tocoflexol: a new radioprotectant tocotrienol with enhanced bioavailability. Drug Dev Res 2013; 75:10-22. [PMID: 24648045 DOI: 10.1002/ddr.21162] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
There is a pressing need to develop safe and effective radioprotector/radiomitigator agents for use in accidental or terrorist-initiated radiological emergencies. Naturally occurring vitamin E family constituents, termed tocols, that include the tocotrienols, are known to have radiation-protection properties. These agents, which work through multiple mechanisms, are promising radioprotectant agents having minimal toxicity. Although α-tocopherol (AT) is the most commonly studied form of vitamin E, the tocotrienols are more potent than AT in providing radioprotection and radiomitigation. Unfortunately, despite their very significant radioprotectant activity, tocotrienols have very short plasma half-lives and require dosing at very high levels to achieve necessary therapeutic benefits. Thus, it would be highly desirable to develop new vitamin E analogues with improved pharmacokinetic properties, specifically increased elimination half-life and increased area under the plasma level versus time curve. The short elimination half-life of the tocotrienols is related to their low affinity for the α-tocopherol transfer protein (ATTP), the protein responsible for maintaining the plasma level of the tocols. Tocotrienols have less affinity for ATTP than does AT, and thus have a longer residence time in the liver, putting them at higher risk for metabolism and biliary excretion. We hypothesized that the low-binding affinity of tocotrienols to ATTP is due to the relatively more rigid tail structure of the tocotrienols in comparison with that of the tocopherols. Therefore, compounds with a more flexible tail would have better binding to ATTP and consequently would have longer elimination half-life and, consequently, an increased exposure to drug, as measured by area under the plasma drug level versus time curve (AUC). This represents an enhanced residence of drug in the systemic circulation. Based on this hypothesis, we developed a new class of vitamin E analogues, the tocoflexols, which maintain the superior bioactivity of the tocotrienols with the potential to achieve the longer half-life and larger AUC of the tocopherols.
Collapse
Affiliation(s)
- Cesar M Compadre
- Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, Little Rock, AR, 72205, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
35
|
Hanada K. Co-evolution of sphingomyelin and the ceramide transport protein CERT. Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1841:704-19. [PMID: 23845852 DOI: 10.1016/j.bbalip.2013.06.006] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2013] [Revised: 06/25/2013] [Accepted: 06/25/2013] [Indexed: 12/15/2022]
Abstract
Life creates many varieties of lipids. The choline-containing sphingophospholipid sphingomyelin (SM) exists ubiquitously or widely in vertebrates and lower animals, but is absent or rare in bacteria, fungi, protists, and plants. In the biosynthesis of SM, ceramide, which is synthesized in the endoplasmic reticulum, is transported to the Golgi region by the ceramide transport protein CERT, probably in a non-vesicular manner, and is then converted to SM by SM synthase, which catalyzes the reaction of phosphocholine transfer from phosphatidylcholine (PtdCho) to ceramide. Recent advances in genomics and lipidomics indicate that the phylogenetic occurrence of CERT and its orthologs is nearly parallel to that of SM. Based on the chemistry of lipids together with evolutionary aspects of SM and CERT, several concepts are here proposed. SM may serve as a chemically inert and robust, but non-covalently interactive lipid class at the outer leaflet of the plasma membrane. The functional domains and peptidic motifs of CERT are separated by exon units, suggesting an exon-shuffling mechanism for the generation of an ancestral CERT gene. CERT may have co-evolved with SM to bypass a competing metabolic reaction at the bifurcated point in the anabolism of ceramide. Human CERT is identical to the splicing variant of human Goodpasture antigen-binding protein (GPBP) annotated as an extracellular non-canonical serine/threonine protein kinase. The relationship between CERT and GPBP has also been discussed from an evolutionary aspect. Moreover, using an analogy of "compatible (or osmoprotective) solutes" that can accumulate to very high concentrations in the cytosol without denaturing proteins, choline phospholipids such as PtdCho and SM may act as compatible phospholipids in biomembranes. This article is part of a Special Issue entitled New Frontiers in Sphingolipid Biology.
Collapse
Affiliation(s)
- Kentaro Hanada
- Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, 1-23-1, Toyama, Shinjuku-ku, Tokyo 162-8640, Japan.
| |
Collapse
|
36
|
Kono N, Ohto U, Hiramatsu T, Urabe M, Uchida Y, Satow Y, Arai H. Impaired -TTP-PIPs Interaction Underlies Familial Vitamin E Deficiency. Science 2013; 340:1106-10. [DOI: 10.1126/science.1233508] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
|
37
|
Li B, Harjani JR, Cormier NS, Madarati H, Atkinson J, Cosa G, Pratt DA. Besting Vitamin E: Sidechain Substitution is Key to the Reactivity of Naphthyridinol Antioxidants in Lipid Bilayers. J Am Chem Soc 2013; 135:1394-405. [DOI: 10.1021/ja309153x] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Bo Li
- Department of Chemistry, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Jitendra R. Harjani
- Department of Chemistry, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Nicholas S. Cormier
- Department of Chemistry, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Hasam Madarati
- Department of Chemistry and
Centre for Biotechnology, Brock University, St. Catharines, Ontario L2S 3A1, Canada
| | - Jeffrey Atkinson
- Department of Chemistry and
Centre for Biotechnology, Brock University, St. Catharines, Ontario L2S 3A1, Canada
| | - Gonzalo Cosa
- Department of Chemistry and Centre
for Self-Assembled Chemical Structures, McGill University, 801 Sherbrooke St. West, Montreal, Quebec H3A 0B8 Canada
| | - Derek A. Pratt
- Department of Chemistry, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| |
Collapse
|
38
|
Abstract
Vitamin E (α-tocopherol) was discovered nearly 100 years ago because it was required to prevent fetal resorption in pregnant, vitamin E-deficient rats fed lard-containing diets that were easily oxidizable. The human diet contains eight different vitamin E-related molecules synthesized by plants; despite the fact that all of these molecules are peroxyl radical scavengers, the human body prefers α-tocopherol. The biological activity of vitamin E is highly dependent upon regulatory mechanisms that serve to retain α-tocopherol and excrete the non-α-tocopherol forms. This preference is dependent upon the combination of the function of α-tocopherol transfer protein (α-TTP) to enrich the plasma with α-tocopherol and the metabolism of non-α-tocopherols. α-TTP is critical for human health because mutations in this protein lead to severe vitamin E deficiency characterized by neurologic abnormalities, especially ataxia and eventually death if vitamin E is not provided in large quantities to overcome the lack of α-TTP. α-Tocopherol serves as a peroxyl radical scavenger that protects polyunsaturated fatty acids in membranes and lipoproteins. Although specific pathways and specific molecular targets have been sought in a variety of studies, the most likely explanation as to why humans require vitamin E is that it is a fat-soluble antioxidant.
Collapse
Affiliation(s)
- Etsuo Niki
- Health Research Institute, AIST, Ikeda, Japan
| | | |
Collapse
|
39
|
Helbling RE, Aeschimann W, Simona F, Stocker A, Cascella M. Engineering tocopherol selectivity in α-TTP: a combined in vitro/in silico study. PLoS One 2012; 7:e49195. [PMID: 23152872 PMCID: PMC3496730 DOI: 10.1371/journal.pone.0049195] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2012] [Accepted: 10/04/2012] [Indexed: 01/21/2023] Open
Abstract
We present a combined in vitro/in silico study to determine the molecular origin of the selectivity of [Formula: see text]-tocopherol transfer protein ([Formula: see text]-TTP) towards [Formula: see text]-tocopherol. Molecular dynamics simulations combined to free energy perturbation calculations predict a binding free energy for [Formula: see text]-tocopherol to [Formula: see text]-TTP 8.26[Formula: see text]2.13 kcal mol[Formula: see text] lower than that of [Formula: see text]-tocopherol. Our calculations show that [Formula: see text]-tocopherol binds to [Formula: see text]-TTP in a significantly distorted geometry as compared to that of the natural ligand. Variations in the hydration of the binding pocket and in the protein structure are found as well. We propose a mutation, A156L, which significantly modifies the selectivity properties of [Formula: see text]-TTP towards the two tocopherols. In particular, our simulations predict that A156L binds preferentially to [Formula: see text]-tocopherol, with striking structural similarities to the wild-type-[Formula: see text]-tocopherol complex. The affinity properties are confirmed by differential scanning fluorimetry as well as in vitro competitive binding assays. Our data indicate that residue A156 is at a critical position for determination of the selectivity of [Formula: see text]-TTP. The engineering of TTP mutants with modulating binding properties can have potential impact at industrial level for easier purification of single tocopherols from vitamin E mixtures coming from natural oils or synthetic processes. Moreover, the identification of a [Formula: see text]-tocopherol selective TTP offers the possibility to challenge the hypotheses for the evolutionary development of a mechanism for [Formula: see text]-tocopherol selection in omnivorous animals.
Collapse
Affiliation(s)
- Rachel E. Helbling
- Department of Chemistry and Biochemistry, University of Bern, Bern, Switzerland
| | - Walter Aeschimann
- Department of Chemistry and Biochemistry, University of Bern, Bern, Switzerland
| | - Fabio Simona
- Department of Chemistry and Biochemistry, University of Bern, Bern, Switzerland
| | - Achim Stocker
- Department of Chemistry and Biochemistry, University of Bern, Bern, Switzerland
| | - Michele Cascella
- Department of Chemistry and Biochemistry, University of Bern, Bern, Switzerland
| |
Collapse
|
40
|
The α-tocopherol transfer protein is essential for vertebrate embryogenesis. PLoS One 2012; 7:e47402. [PMID: 23077608 PMCID: PMC3471827 DOI: 10.1371/journal.pone.0047402] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Accepted: 09/14/2012] [Indexed: 11/20/2022] Open
Abstract
The hepatic α-tocopherol transfer protein (TTP) is required for optimal α-tocopherol bioavailability in humans; mutations in the human TTPA gene result in the heritable disorder ataxia with vitamin E deficiency (AVED, OMIM #277460). TTP is also expressed in mammalian uterine and placental cells and in the human embryonic yolk-sac, underscoring TTP’s significance during fetal development. TTP and vitamin E are essential for productive pregnancy in rodents, but their precise physiological role in embryogenesis is unknown. We hypothesize that TTP is required to regulate delivery of α-tocopherol to critical target sites in the developing embryo. We tested to find if TTP is essential for proper vertebrate development, utilizing the zebrafish as a non-placental model. We verify that TTP is expressed in the adult zebrafish and its amino acid sequence is homologous to the human ortholog. We show that embryonic transcription of TTP mRNA increases >7-fold during the first 24 hours following fertilization. In situ hybridization demonstrates that Ttpa transcripts are localized in the developing brain, eyes and tail bud at 1-day post fertilization. Inhibiting TTP expression using oligonucleotide morpholinos results in severe malformations of the head and eyes in nearly all morpholino-injected embryos (88% compared with 5.6% in those injected with control morpholinos or 1.7% in non-injected embryos). We conclude that TTP is essential for early development of the vertebrate central nervous system.
Collapse
|
41
|
Pan CQ, Low BC. Functional plasticity of the BNIP-2 and Cdc42GAP Homology (BCH) domain in cell signaling and cell dynamics. FEBS Lett 2012; 586:2674-91. [DOI: 10.1016/j.febslet.2012.04.023] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Revised: 04/16/2012] [Accepted: 04/16/2012] [Indexed: 10/28/2022]
|
42
|
Gupta AB, Wee LE, Zhou YT, Hortsch M, Low BC. Cross-species analyses identify the BNIP-2 and Cdc42GAP homology (BCH) domain as a distinct functional subclass of the CRAL_TRIO/Sec14 superfamily. PLoS One 2012; 7:e33863. [PMID: 22479462 PMCID: PMC3313917 DOI: 10.1371/journal.pone.0033863] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2011] [Accepted: 02/18/2012] [Indexed: 11/19/2022] Open
Abstract
The CRAL_TRIO protein domain, which is unique to the Sec14 protein superfamily, binds to a diverse set of small lipophilic ligands. Similar domains are found in a range of different proteins including neurofibromatosis type-1, a Ras GTPase-activating Protein (RasGAP) and Rho guanine nucleotide exchange factors (RhoGEFs). Proteins containing this structural protein domain exhibit a low sequence similarity and ligand specificity while maintaining an overall characteristic three-dimensional structure. We have previously demonstrated that the BNIP-2 and Cdc42GAP Homology (BCH) protein domain, which shares a low sequence homology with the CRAL_TRIO domain, can serve as a regulatory scaffold that binds to Rho, RhoGEFs and RhoGAPs to control various cell signalling processes. In this work, we investigate 175 BCH domain-containing proteins from a wide range of different organisms. A phylogenetic analysis with ∼100 CRAL_TRIO and similar domains from eight representative species indicates a clear distinction of BCH-containing proteins as a novel subclass within the CRAL_TRIO/Sec14 superfamily. BCH-containing proteins contain a hallmark sequence motif R(R/K)h(R/K)(R/K)NL(R/K)xhhhhHPs (‘h’ is large and hydrophobic residue and ‘s’ is small and weekly polar residue) and can be further subdivided into three unique subtypes associated with BNIP-2-N, macro- and RhoGAP-type protein domains. A previously unknown group of genes encoding ‘BCH-only’ domains is also identified in plants and arthropod species. Based on an analysis of their gene-structure and their protein domain context we hypothesize that BCH domain-containing genes evolved through gene duplication, intron insertions and domain swapping events. Furthermore, we explore the point of divergence between BCH and CRAL-TRIO proteins in relation to their ability to bind small GTPases, GAPs and GEFs and lipid ligands. Our study suggests a need for a more extensive analysis of previously uncharacterized BCH, ‘BCH-like’ and CRAL_TRIO-containing proteins and their significance in regulating signaling events involving small GTPases.
Collapse
Affiliation(s)
- Anjali Bansal Gupta
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
- Mechanobiology Institute, National University of Singapore, Singapore, Singapore
| | - Liang En Wee
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Yi Ting Zhou
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Michael Hortsch
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Boon Chuan Low
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
- Mechanobiology Institute, National University of Singapore, Singapore, Singapore
- * E-mail:
| |
Collapse
|
43
|
Bankaitis VA, Ile KE, Nile AH, Ren J, Ghosh R, Schaaf G. Thoughts on Sec14-like nanoreactors and phosphoinositide signaling. Adv Biol Regul 2012; 52:115-21. [PMID: 22776890 DOI: 10.1016/j.jbior.2011.11.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2011] [Accepted: 11/11/2011] [Indexed: 10/28/2022]
Affiliation(s)
- Vytas A Bankaitis
- Department of Cell & Developmental Biology, Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599-7090, USA.
| | | | | | | | | | | |
Collapse
|
44
|
Devising Powerful Genetics, Biochemical and Structural Tools in the Functional Analysis of Phosphatidylinositol Transfer Proteins (PITPs) Across Diverse Species. Methods Cell Biol 2012; 108:249-302. [DOI: 10.1016/b978-0-12-386487-1.00013-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
|
45
|
Mousley CJ, Davison JM, Bankaitis VA. Sec14 like PITPs couple lipid metabolism with phosphoinositide synthesis to regulate Golgi functionality. Subcell Biochem 2012; 59:271-87. [PMID: 22374094 DOI: 10.1007/978-94-007-3015-1_9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
An interface coordinating lipid metabolism with proteins that regulate membrane trafficking is necessary to regulate Golgi morphology and dynamics. Such an interface facilitates the membrane deformations required for vesicularization, forms platforms for protein recruitment and assembly on appropriate sites on a membrane surface and provides lipid co-factors for optimal protein activity in the proper spatio-temporally regulated manner. Importantly, Sec14 and Sec14-like proteins are a unique superfamily of proteins that sense specific aspects of lipid metabolism, employing this information to potentiate phosphoinositide production. Therefore, Sec14 and Sec14 like proteins form central conduits to integrate multiple aspects of lipid metabolism with productive phosphoinositide signaling.
Collapse
Affiliation(s)
- Carl J Mousley
- Department of Cell & Developmental Biology, Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, 27599-7090, Chapel Hill, NC, USA,
| | | | | |
Collapse
|
46
|
Shichiri M, Kono N, Shimanaka Y, Tanito M, Rotzoll DE, Yoshida Y, Hagihara Y, Tamai H, Arai H. A novel role for α-tocopherol transfer protein (α-TTP) in protecting against chloroquine toxicity. J Biol Chem 2011; 287:2926-34. [PMID: 22147702 PMCID: PMC3268449 DOI: 10.1074/jbc.m111.321281] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Chloroquine (CQ) is a widely prescribed anti-malarial agent and is also prescribed to treat autoimmune diseases. Clinical treatment with CQ is often accompanied by serious side effects such as hepatitis and retinopathy. As a weak base, CQ accumulates in intracellular acidic organelles, raises the pH, and induces osmotic swelling and permeabilization of acidic organelles, which account for CQ-induced cytotoxicity. We reported previously that CQ treatment caused α-tocopherol transfer protein (α-TTP), a gene product of familial vitamin E deficiency, to change its location from the cytosol to the surface of acidic organelles. Here we show that α-TTP plays a novel role in protecting against CQ toxicity both in vitro and in vivo. In the presence of CQ, rat hepatoma McARH7777 cells, which do not express α-TTP endogenously, showed more severe cytotoxicity, such as larger vacuolation of acidic organelles and caspase activation, than α-TTP transfectant cells. Similarly, α-TTP knockout mice showed more severe CQ toxicity, such as hepatotoxicity and retinopathy, than wild-type mice. These effects were not ameliorated by vitamin E supplementation. In contrast to bafilomycin A1 treatment, which prevents CQ accumulation in cells by raising the pH of acidic organelles, α-TTP expression prevented CQ accumulation without affecting the pH of acidic organelles. Taken together, our data suggest that α-TTP protects against CQ toxicity by preventing CQ accumulation in acidic organelles through a mechanism distinct from vitamin E transport.
Collapse
Affiliation(s)
- Mototada Shichiri
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | | | | | | | | | | | | | | | | |
Collapse
|
47
|
Sabarinathan R, Aishwarya K, Sarani R, Vaishnavi MK, Sekar K. Water-mediated ionic interactions in protein structures. J Biosci 2011; 36:253-63. [PMID: 21654080 DOI: 10.1007/s12038-011-9067-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
It is well known that water molecules play an indispensable role in the structure and function of biological macromolecules. The water-mediated ionic interactions between the charged residues provide stability and plasticity and in turn address the function of the protein structures. Thus, this study specifically addresses the number of possible water-mediated ionic interactions, their occurrence, distribution and nature found in 90% non-redundant protein chains. Further, it provides a statistical report of different charged residue pairs that are mediated by surface or buried water molecules to form the interactions. Also, it discusses its contributions in stabilizing various secondary structural elements of the protein. Thus, the present study shows the ubiquitous nature of the interactions that imparts plasticity and flexibility to a protein molecule.
Collapse
Affiliation(s)
- R Sabarinathan
- Bioinformatics Centre, Centre of Excellence in Structural Biology and Bio-computing, Indian Institute of Science, Bangalore 560012, India
| | | | | | | | | |
Collapse
|
48
|
Ren J, Schaaf G, Bankaitis VA, Ortlund EA, Pathak MC. Crystallization and preliminary X-ray diffraction analysis of Sfh3, a member of the Sec14 protein superfamily. Acta Crystallogr Sect F Struct Biol Cryst Commun 2011; 67:1239-43. [PMID: 22102037 PMCID: PMC3212372 DOI: 10.1107/s1744309111027096] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2011] [Accepted: 07/06/2011] [Indexed: 11/10/2022]
Abstract
Sec14 is the major phosphatidylinositol (PtdIns)/phosphatidylcholine (PtdCho) transfer protein in the yeast Saccharomyces cerevisiae and is the founding member of the Sec14 protein superfamily. Recent functional data suggest that Sec14 functions as a nanoreactor for PtdCho-regulated presentation of PtdIns to PtdIns kinase to affect membrane trafficking. Extrapolation of this concept to other members of the Sec14 superfamily suggests a mechanism by which a comprehensive cohort of Sec14-like nanoreactors sense correspondingly diverse pools of lipid metabolites. In turn, metabolic information is translated to signaling circuits driven by phosphoinositide metabolism. Sfh3, one of five Sec14 homologs in yeast, exhibits several interesting functional features, including its unique localization to lipid particles and microsomes. This localization forecasts novel regulatory interfaces between neutral lipid metabolism and phosphoinositide signaling. To launch a detailed structural and functional characterization of Sfh3, the recombinant protein was purified to homogeneity, diffraction-quality crystals were produced and a native X-ray data set was collected to 2.2 Å resolution. To aid in phasing, SAD X-ray diffraction data were collected to 1.93 Å resolution from an SeMet-labeled crystal at the Southeast Regional Collaborative Access Team at the Advanced Photon Source. Here, the cloning and purification of Sfh3 and the preliminary diffraction of Sfh3 crystals are reported, enabling structural analyses that are expected to reveal novel principles governing ligand binding and functional specificity for Sec14-superfamily proteins.
Collapse
Affiliation(s)
- Jihui Ren
- Department of Cell and Developmental Biology, Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599-7090, USA
| | - Gabriel Schaaf
- Department of Cell and Developmental Biology, Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599-7090, USA
| | - Vytas A. Bankaitis
- Department of Cell and Developmental Biology, Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599-7090, USA
| | - Eric A. Ortlund
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Manish C. Pathak
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA
| |
Collapse
|
49
|
Ghosh R, Bankaitis VA. Phosphatidylinositol transfer proteins: negotiating the regulatory interface between lipid metabolism and lipid signaling in diverse cellular processes. Biofactors 2011; 37:290-308. [PMID: 21915936 DOI: 10.1002/biof.180] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Phosphoinositides represent only a small percentage of the total cellular lipid pool. Yet, these molecules play crucial roles in diverse intracellular processes such as signal transduction at membrane-cytosol interface, regulation of membrane trafficking, cytoskeleton organization, nuclear events, and the permeability and transport functions of the membrane. A central principle in such lipid-mediated signaling is the appropriate coordination of these events. Such an intricate coordination demands fine spatial and temporal control of lipid metabolism and organization, and consistent mechanisms for specifically coupling these parameters to dedicated physiological processes. In that regard, recent studies have identified Sec14-like phosphatidylcholine transfer protein (PITPs) as "coincidence detectors," which spatially and temporally link the diverse aspects of the cellular lipid metabolome with phosphoinositide signaling. The integral role of PITPs in eukaryotic signal transduction design is amply demonstrated by the mammalian diseases associated with the derangements in the function of these proteins, to stress response and developmental regulation in plants, to fungal dimorphism and pathogenicity, to membrane trafficking in yeast, and higher eukaryotes. This review updates the recent advances made in the understanding of how these proteins, specifically PITPs of the Sec14-protein superfamily, operate at the molecular level and further describes how this knowledge has advanced our perception on the diverse biological functions of PITPs.
Collapse
Affiliation(s)
- Ratna Ghosh
- Lineberger Comprehensive Cancer Center, Department of Cell and Developmental Biology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27526-7090, USA.
| | | |
Collapse
|
50
|
Gee PT. Unleashing the untold and misunderstood observations on vitamin E. GENES & NUTRITION 2011; 6:5-16. [PMID: 21437026 PMCID: PMC3040795 DOI: 10.1007/s12263-010-0180-z] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2010] [Accepted: 07/07/2010] [Indexed: 02/07/2023]
Abstract
Paradoxically, meta-analysis of human randomized controlled trials revealed that natural but not synthetic α-tocopherol supplementation significantly increases all-cause mortality at 95% confidence interval. The root cause was that natural α-tocopherol supplementation significantly depressed bioavailability of other forms of vitamin E that have better chemo-prevention capability. Meta-analysis outcome demonstrated flaws in the understanding of vitamin E. Reinterpretation of reported data provides plausible explanations to several important observations. While α-tocopherol is almost exclusively secreted in chylomicrons, enterocytes secrete tocotrienols in both chylomicrons and small high-density lipoproteins. Vitamin E secreted in chylomicrons is discriminately repacked by α-tocopherol transfer protein into nascent very low-density lipoproteins in the liver. Circulating very low-density lipoproteins undergo delipidation to form intermediate-density lipoproteins and low-density lipoproteins. Uptake of vitamin E in intermediate-density lipoproteins and low-density lipoproteins takes place at various tissues via low-density lipoproteins receptor-mediated endocytosis. Small high-density lipoproteins can deliver tocotrienols upon maturation to peripheral tissues independent of α-tocopherol transfer protein action, and uptake of vitamin E takes place at selective tissues by scavenger receptor-mediated direct vitamin E uptake. Dual absorption pathways for tocotrienols are consistent with human and animal studies. α-Tocopherol depresses the bioavailability of α-tocotrienol and has antagonistic effect on tocotrienols in chemo-prevention against degenerative diseases. Therefore, it is an undesirable component for chemo-prevention. Future research directions should be focused on tocotrienols, preferably free from α-tocopherol, for optimum chemo-prevention and benefits to mankind.
Collapse
Affiliation(s)
- Ping Tou Gee
- Palm Nutraceuticals Sdn. Bhd., Batu 7, Jalan Mawai, 81900 Kota Tinggi, Johor Malaysia
| |
Collapse
|