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Rosenberg EM, Jian X, Soubias O, Jackson RA, Gladu E, Andersen E, Esser L, Sodt AJ, Xia D, Byrd RA, Randazzo PA. Point mutations in Arf1 reveal cooperative effects of the N-terminal extension and myristate for GTPase-activating protein catalytic activity. PLoS One 2024; 19:e0295103. [PMID: 38574162 PMCID: PMC10994351 DOI: 10.1371/journal.pone.0295103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Accepted: 03/05/2024] [Indexed: 04/06/2024] Open
Abstract
The ADP-ribosylation factors (Arfs) constitute a family of small GTPases within the Ras superfamily, with a distinguishing structural feature of a hypervariable N-terminal extension of the G domain modified with myristate. Arf proteins, including Arf1, have roles in membrane trafficking and cytoskeletal dynamics. While screening for Arf1:small molecule co-crystals, we serendipitously solved the crystal structure of the non-myristoylated engineered mutation [L8K]Arf1 in complex with a GDP analogue. Like wild-type (WT) non-myristoylated Arf1•GDP, we observed that [L8K]Arf1 exhibited an N-terminal helix that occludes the hydrophobic cavity that is occupied by the myristoyl group in the GDP-bound state of the native protein. However, the helices were offset from one another due to the L8K mutation, with a significant change in position of the hinge region connecting the N-terminus to the G domain. Hypothesizing that the observed effects on behavior of the N-terminus affects interaction with regulatory proteins, we mutated two hydrophobic residues to examine the role of the N-terminal extension for interaction with guanine nucleotide exchange factors (GEFs) and GTPase Activating Proteins (GAPs. Different than previous studies, all mutations were examined in the context of myristoylated Arf. Mutations had little or no effect on spontaneous or GEF-catalyzed guanine nucleotide exchange but did affect interaction with GAPs. [F13A]myrArf1 was less than 1/2500, 1/1500, and 1/200 efficient as substrate for the GAPs ASAP1, ARAP1 and AGAP1; however, [L8A/F13A]myrArf1 was similar to WT myrArf1. Using molecular dynamics simulations, the effect of the mutations on forming alpha helices adjacent to a membrane surface was examined, yet no differences were detected. The results indicate that lipid modifications of GTPases and consequent anchoring to a membrane influences protein function beyond simple membrane localization. Hypothetical mechanisms are discussed.
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Affiliation(s)
- Eric M. Rosenberg
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, MD, United States of America
| | - Xiaoying Jian
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, MD, United States of America
| | - Olivier Soubias
- Section of Macromolecular NMR, Center for Structural Biology Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD, United States of America
| | - Rebekah A. Jackson
- Section of Macromolecular NMR, Center for Structural Biology Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD, United States of America
| | - Erin Gladu
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, MD, United States of America
| | - Emily Andersen
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, MD, United States of America
| | - Lothar Esser
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, United States of America
| | - Alexander J. Sodt
- Unit of Membrane Chemical Physics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD, United States of America
| | - Di Xia
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, United States of America
| | - R. Andrew Byrd
- Section of Macromolecular NMR, Center for Structural Biology Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD, United States of America
| | - Paul A. Randazzo
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, MD, United States of America
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Hu T, Zhang W, Han F, Zhao R, Liu H, An Z. Machine learning reveals serum myristic acid, palmitic acid and heptanoylcarnitine as biomarkers of coronary artery disease risk in patients with type 2 diabetes mellitus. Clin Chim Acta 2024; 556:117852. [PMID: 38438006 DOI: 10.1016/j.cca.2024.117852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 01/25/2024] [Accepted: 03/01/2024] [Indexed: 03/06/2024]
Abstract
BACKGROUND Coronary heart disease (CHD) is the most important complication of type 2 diabetes mellitus (T2DM) and the leading cause of death. Identifying the risk of CHD in T2DM patients is important for early clinical intervention. METHODS A total of 213 participants, including 81 healthy controls (HCs), 69 T2DM patients and 63 T2DM patients complicated with CHD were recruited in this study. Serum metabolomics were conducted by using ultra-high performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS). Demographic information and clinical laboratory test results were also collected. RESULTS Metabolic phenotypes were significantly altered among HC, T2DM and T2DM-CHD. Acylcarnitines were the most disturbed metabolites between T2DM patients and HCs. Lower levels of bile acids and higher levels of fatty acids in serum were closely associated with CHD risk in T2DM patients. Artificial neural network model was constructed for the discrimination of T2DM and T2DM complicated with CHD based on myristic acid, palmitic acid and heptanoylcarnitine, with accuracy larger than 0.95 in both training set and testing set. CONCLUSION Altogether, these findings suggest that myristic acid, palmitic acid and heptanoylcarnitine have a good prospect for the warning of CHD complications in T2DM patients, and are superior to traditional lipid, blood glucose and blood pressure indicators.
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Affiliation(s)
- Ting Hu
- Beijing Chao-Yang Hospital, Capital Medical University, No.8 Gongti South Road, Chaoyang District, Beijing 100020, PR China.
| | - Wen Zhang
- Beijing Chao-Yang Hospital, Capital Medical University, No.8 Gongti South Road, Chaoyang District, Beijing 100020, PR China
| | - Feifei Han
- Beijing Chao-Yang Hospital, Capital Medical University, No.8 Gongti South Road, Chaoyang District, Beijing 100020, PR China
| | - Rui Zhao
- Beijing Chao-Yang Hospital, Capital Medical University, No.8 Gongti South Road, Chaoyang District, Beijing 100020, PR China
| | - Hongchuan Liu
- Beijing Chao-Yang Hospital, Capital Medical University, No.8 Gongti South Road, Chaoyang District, Beijing 100020, PR China
| | - Zhuoling An
- Beijing Chao-Yang Hospital, Capital Medical University, No.8 Gongti South Road, Chaoyang District, Beijing 100020, PR China.
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Mondal T, Mondal S, Ghosh SK, Pal P, Soren T, Maiti TK. Dibutyl phthalate degradation by Paenarthrobacter ureafaciens PB10 through downstream product myristic acid and its bioremediation potential in contaminated soil. Chemosphere 2024; 352:141359. [PMID: 38309604 DOI: 10.1016/j.chemosphere.2024.141359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 01/30/2024] [Accepted: 01/31/2024] [Indexed: 02/05/2024]
Abstract
Dibutyl phthalate (DBP) is a widely used plasticizer to make plastic flexible and long-lasting. It is easily accessible in a broad spectrum of environments as a result of the rising level of plastic pollution. This compound is considered a top-priority toxicant and persistent organic pollutant by international environmental agencies for its endocrine disruptive and carcinogenic propensities. To mitigate the DBP in the soil, one DBP-degrading bacterial strain was isolated from a plastic-polluted landfill and identified as Paenarthrobacter ureafaciens PB10 by 16S rRNA gene sequence-based homology. The strain was found to develop a distinct transparent halo zone around grown colonies on an agar plate supplemented with DBP. The addition of yeast extract (100 mg/L) as a nutrient source accelerated cell biomass production and DBP degradation rate; however, the presence of glucose suppressed DBP degradation by the PB10 strain without affecting its ability to proliferate. The strain PB10 was efficient in eliminating DBP under various pH conditions (5.0-8.0). Maximum cell growth and degradation of 99.49% at 300 mg/L DBP were achieved in 72 h at the optimized mineral salt medium (MS) conditions of pH 7.0 and 32 °C. Despite that, when the concentration of DBP rose to 3000 mg/L, the DBP depletion rate was measured at 79.34% in 72 h. Some novel intermediate metabolites, like myristic acid, hexadecanoic acid, stearic acid, and the methyl derivative of 4-hydroxyphenyl acetate, along with monobutyl phthalate and phthalic acid, were detected in the downstream degradation process of DBP through GC-MS profiling. Furthermore, in synchronization with native soil microbes, this PB10 strain successfully removed a notable amount of DBP (up to 54.11%) from contaminated soil under microcosm study after 10 d. Thus, PB10 has effective DBP removal ability and is considered a potential candidate for bioremediation in DBP-contaminated sites.
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Affiliation(s)
- Tanushree Mondal
- Microbiology Laboratory, Department of Botany, The University of Burdwan, Golapbag, Purba Bardhaman, P. O. -Rajbati, PIN-713104, West Bengal, India.
| | - Sayanta Mondal
- Microbiology Laboratory, Department of Botany, The University of Burdwan, Golapbag, Purba Bardhaman, P. O. -Rajbati, PIN-713104, West Bengal, India.
| | - Sudip Kumar Ghosh
- Microbiology Laboratory, Department of Botany, The University of Burdwan, Golapbag, Purba Bardhaman, P. O. -Rajbati, PIN-713104, West Bengal, India.
| | - Priyanka Pal
- Microbiology Laboratory, Department of Botany, The University of Burdwan, Golapbag, Purba Bardhaman, P. O. -Rajbati, PIN-713104, West Bengal, India
| | - Tithi Soren
- Microbiology Laboratory, Department of Botany, The University of Burdwan, Golapbag, Purba Bardhaman, P. O. -Rajbati, PIN-713104, West Bengal, India.
| | - Tushar Kanti Maiti
- Microbiology Laboratory, Department of Botany, The University of Burdwan, Golapbag, Purba Bardhaman, P. O. -Rajbati, PIN-713104, West Bengal, India.
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Almushawah MA, Athinarayanan J, Periasamy VS, Alshatwi AA. Fabrication of myristic acid-potato starch complex nanostructures and assessment of their cytotoxic behavior. J Sci Food Agric 2024; 104:1813-1823. [PMID: 37872732 DOI: 10.1002/jsfa.13071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Revised: 08/09/2023] [Accepted: 10/24/2023] [Indexed: 10/25/2023]
Abstract
BACKGROUND Lipids and carbohydrates perform essential functions in foods. In recent decades, food scientists have studied the effects of carbohydrate-lipid interactions on the functional properties of food. However, the ways in which carbohydrate-lipid complex-derived materials affect the biological system are unknown. In this study, a myristic acid-potato starch complex was created using a simple cooking approach. The complex was employed as a precursor for the fabrication of myristic acid-potato starch complex-based nanostructured materials (MPS-NMs) through a liquid-liquid extraction approach. A study was conducted on the structural and cytotoxic features of the fabricated MPS-NMs. RESULTS Transmission electron microscopy images confirmed the formation of spherical nanostructures, 3-60 nm in size. After 24 h exposure, the chloroform fraction-based and n-hexane fraction-based MPS-NMs increased cell death by ~90% and ~ 82%, respectively. Chloroform fraction-based MPS-NMs (CMPS-NMs) triggers apoptotic cell death in human mesenchymal stem cells (hMSCs). n-Hexane fraction-based MPS-NMs (HMPS-NMs) treated cells have red color-intact nuclei, attributed to necrotic cell death. The CMPS-NMs and HMPS-NMs significantly decreased the mitochondria membrane potential and increased the intracellular reactive oxygen species (ROS) levels. We observed significant downregulation in flavin-containing monooxygenase (FMO), Ataxia Telangiectasia Mutated (ATM), and uridine diphosphate glucuronosyltransferases (UGT) gene expression levels in the exposed cells of CMPS-NMs and HMPS- NMs. In addition, we found upregulation of glutathione-disulfide reductase (GSR) and glutathione S-transferase A4 (GSTA4) genes in CMPS-NMs, and HMPS-NMs exposure. CONCLUSION The cooking process may lead to the formation of nanostructured material in food systems. Chloroform fraction-based MPS-NMs and HMPS-NMs may contribute to cell metabolic disorders. © 2023 Society of Chemical Industry.
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Affiliation(s)
- Mushawah Abdullah Almushawah
- Nanobiotechnology and Molecular Biology Research Laboratory, Department of Food Science and Nutrition, College of Food Science and Agriculture, King Saud University, Riyadh, Saudi Arabia
| | - Jegan Athinarayanan
- Nanobiotechnology and Molecular Biology Research Laboratory, Department of Food Science and Nutrition, College of Food Science and Agriculture, King Saud University, Riyadh, Saudi Arabia
| | - Vaiyapuri Subbarayan Periasamy
- Nanobiotechnology and Molecular Biology Research Laboratory, Department of Food Science and Nutrition, College of Food Science and Agriculture, King Saud University, Riyadh, Saudi Arabia
| | - Ali A Alshatwi
- Nanobiotechnology and Molecular Biology Research Laboratory, Department of Food Science and Nutrition, College of Food Science and Agriculture, King Saud University, Riyadh, Saudi Arabia
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Jiang Y, Wu H, Ho PCL, Tang X, Ao H, Chen L, Cai J. GC-MS Fingerprinting Combined with Chemical Pattern-Recognition Analysis Reveals Novel Chemical Markers of the Medicinal Seahorse. Molecules 2023; 28:7824. [PMID: 38067553 PMCID: PMC10708380 DOI: 10.3390/molecules28237824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 11/17/2023] [Accepted: 11/23/2023] [Indexed: 12/18/2023] Open
Abstract
Seahorse is a valuable marine-animal drug widely used in traditional Chinese medicine (TCM), and which was first documented in the "Ben Cao Jing Ji Zhu" during the Liang Dynasty. Hippocampus kelloggi (HK) is the most common seahorse species in the medicinal material market and is one of the genuine sources of medicinal seahorse documented in the Chinese pharmacopeia. It is mainly cultivated in the Shandong, Fujian, and Guangxi Provinces in China. However, pseudo-HK, represented by Hippocampus ingens (HI) due to its similar appearance and traits, is often found in the market, compromising the safety and efficacy of clinical use. Currently, there is a lack of reliable methods for identifying these species based on their chemical composition. In this study, we employed, for the first time, a strategy combining gas chromatography-mass spectrometry (GC-MS) fingerprints and chemical patterns in order to identify HK and HI; it is also the first metabolomic study to date of HI as to chemical components. The obtained results revealed remarkable similarities in the chemical fingerprints, while significant differences were also observed. By employing hierarchical cluster analysis (HCA) and principal component analysis (PCA), based on the relative contents of their characteristic peaks, all 34 samples were successfully differentiated according to their species of origin, with samples from the same species forming distinct clusters. Moreover, nonadecanoic acid and behenic acid were exclusively detected in HK samples, further distinguishing them from HI samples. Additionally, the relative contents of lauric acid, tetradecanoic acid, pentadecanoic acid, n-hexadecanoic acid, palmitoleic acid, margaric acid, oleic acid, fenozan acid, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) exhibited significant differences between HK and HI (p < 0.0001), as determined by an unpaired t-test. Orthogonal partial least squares discriminant analysis (OPLS-DA) identified seven components (DHA, EPA, n-hexadecanoic acid, tetradecanoic acid, palmitoleic acid, octadecanoic acid, and margaric acid) with high discriminatory value (VIP value > 1). Thus, nonadecanoic acid, behenic acid, and these seven compounds can be utilized as chemical markers for distinguishing HK from HI. In conclusion, our study successfully developed a combined strategy of GC-MS fingerprinting and chemical pattern recognition for the identification of HK and HI, and we also discovered chemical markers that can directly differentiate between the two species. This study can provide a foundation for the authentication of Hippocampus and holds significant importance for the conservation of wild seahorse resources.
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Affiliation(s)
- Yuanyuan Jiang
- State Key Laboratory of Southwestern Chinese Medicine Resources, School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China; (Y.J.); (H.W.); (H.A.)
| | - Hongfei Wu
- State Key Laboratory of Southwestern Chinese Medicine Resources, School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China; (Y.J.); (H.W.); (H.A.)
| | - Paul Chi Lui Ho
- School of Pharmacy, Monash University Malaysia, Subang Jaya 47500, Malaysia;
| | - Xuemei Tang
- Chengdu Institute of Food Inspection, Chengdu 610045, China;
| | - Hui Ao
- State Key Laboratory of Southwestern Chinese Medicine Resources, School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China; (Y.J.); (H.W.); (H.A.)
- Innovative Institute of Chinese Medicine and Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China
| | - Lu Chen
- State Key Laboratory of Southwestern Chinese Medicine Resources, School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China; (Y.J.); (H.W.); (H.A.)
| | - Jinjin Cai
- Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu 610075, China
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Davoudi S, Raemdonck K, Braeckmans K, Ghysels A. Capric Acid and Myristic Acid Permeability Enhancers in Curved Liposome Membranes. J Chem Inf Model 2023; 63:6789-6806. [PMID: 37917127 DOI: 10.1021/acs.jcim.3c00936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2023]
Abstract
Liposomes are considered as advanced drug delivery systems for cancer treatment. A generation of pH-sensitive liposomes is being developed that use fatty acids (FAs) as a trigger for drug release in tumor tissues. However, FAs are also known to enhance permeability, and it is unclear whether FAs in liposomes may cause drug leakage or premature drug release. The passive permeability of the drug through the membrane of the liposome is thus a crucial factor for timely drug delivery. To investigate how the curvature and lipid composition of liposomes affect their passive permeability, coarse-grained molecular dynamics were performed. The permeability was determined with a counting method. Flat bilayers and three liposomes with varying diameters were studied, which had varying lipid compositions of dipalmitoylphosphatidylcholine, cholesterol, and deprotonated or neutral saturated FAs. The investigated permeants were water and two other small permeants, which have different free energy profiles (solubility) across the membrane. First, for the curvature effect, our results showed that curvature increases the water permeability by reducing the membrane thickness. The permeability increase for water is about a factor of 1.7 for the most curved membranes. However, a high curvature decreases permeability for permeants with free energy profiles that are a mix of wells and barriers in the headgroup region of the membrane. Importantly, the type of experimental setup is expected to play a dominant role in the permeability value, i.e., whether permeants are escaping or entering the liposomes. Second, for the composition effect, FAs decrease both the area per lipid (APL) and the membrane thickness, resulting in permeability increases of up to 55%. Cholesterol has a similar effect on the APL but has the opposite impact on membrane thickness and permeability. Therefore, FAs and cholesterol have opposing effects on permeability, with cholesterol's effect being slightly stronger in our simulated bilayers. As all permeability values were well within a factor of 2, and with liposomes usually being larger and less curved in experimental applications, it can be concluded that the passive drug release from a pH-sensitive liposome does not seem to be significantly affected by the presence of FAs.
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Affiliation(s)
- Samaneh Davoudi
- IBiTech─BioMMedA Group, Ghent University, Corneel Heymanslaan 10, Block B-Entrance 36, 9000 Gent, Belgium
| | - Koen Raemdonck
- Ghent Research Group on Nanomedicines, Laboratory for General Biochemistry and Physical Pharmacy, Ghent University, Ottergemsesteenweg 460, 9000 Gent, Belgium
| | - Kevin Braeckmans
- Bio-Photonic Imaging Group, Laboratory for General Biochemistry and Physical Pharmacy, Ghent University, Ottergemsesteenweg 460, 9000 Gent, Belgium
| | - An Ghysels
- IBiTech─BioMMedA Group, Ghent University, Corneel Heymanslaan 10, Block B-Entrance 36, 9000 Gent, Belgium
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Sun D, Yang X, Wang Y, Fan Y, Ding P, Song X, Yuan X, Yang X. Stronger mutualistic interactions with arbuscular mycorrhizal fungi help Asteraceae invaders outcompete the phylogenetically related natives. New Phytol 2022; 236:1487-1496. [PMID: 35975696 DOI: 10.1111/nph.18435] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Accepted: 08/04/2022] [Indexed: 06/15/2023]
Abstract
Mutualistic interactions with arbuscular mycorrhizal fungi (AMF) greatly affect the outcome of plant-plant competition, especially for invasive plants competing against native plants. We examined the effects of AMF on the competition between invasive Asteraceae plants and the phylogenetically related native plants. We compared the performance of seven invasive Asteraceae plants from different genera with that of their phylogenetically related native counterparts in response to AMF in monocultures and mixed cultures. We investigated how interactions with AMF impact the competition between Asteraceae relatives. Total biomass increased with AMF colonization in both invasive and native plants. Arbuscular mycorrhizal fungi improved the competitiveness of invasive plants, but decreased that of native plants. Competition increased the shoot nitrogen, phosphorus and root myristic acid concentrations and relative expression of fatty acid transporter genes (RiFAT1 and RiFAT2) in AMF-colonized invasive plants, but decreased those in AMF-colonized native plants. Structural equation models indicated that the presence of AMF increased the uptake of phosphorus, but not nitrogen, by invasive plants, which probably provided more myristic acids to symbiotic AMF in return. These results suggest that invasive Asteraceae plants have greater mutualistic interactions with AMF than their phylogenetically related native counterparts, potentially contributing to invasion success.
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Affiliation(s)
- Dasheng Sun
- College of Resources and Environment, Shanxi Agricultural University, Taigu, 030801, China
| | - Xueping Yang
- College of Agriculture, Shanxi Agricultural University, Taigu, 030801, China
| | - Yi Wang
- Yunnan Key Laboratory of Plant Reproductive Adaptation and Evolutionary Ecology and Centre for Invasion Biology, Institute of Biodiversity, School of Ecology and Environmental Science, Yunnan University, Kunming, 650504, China
| | - Yu Fan
- College of Agriculture, Shanxi Agricultural University, Taigu, 030801, China
| | - Pengcheng Ding
- College of Agriculture, Shanxi Agricultural University, Taigu, 030801, China
| | - Xi'E Song
- College of Agriculture, Shanxi Agricultural University, Taigu, 030801, China
| | - Xiangyang Yuan
- College of Agriculture, Shanxi Agricultural University, Taigu, 030801, China
| | - Xuefang Yang
- College of Agriculture, Shanxi Agricultural University, Taigu, 030801, China
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Oliveira SDSDC, Sarmento EDS, Marinho VH, Pereira RR, Fonseca LP, Ferreira IM. Green Extraction of Annatto Seed Oily Extract and Its Use as a Pharmaceutical Material for the Production of Lipid Nanoparticles. Molecules 2022; 27:molecules27165187. [PMID: 36014427 PMCID: PMC9412625 DOI: 10.3390/molecules27165187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2022] [Revised: 08/03/2022] [Accepted: 08/10/2022] [Indexed: 12/04/2022] Open
Abstract
This work developd nanomaterials formulated from annatto seed oily extract (ASE), myristic acid (tetradecanoic acid), and their fatty acid esters. The annatto seed oily extract was obtained using only soybean oil (ASE + SO) and Brazil nut oil (ASE + BNO). The UV/VIS analysis of the oily extracts showed three characteristic peaks of the bixin molecule at 430, 456 and 486 nm. The lipid nanoparticles obtained using myristic acid and ASE + BNO or only BNO showed better results than the oil soybean extract, i.e., the particle size was <200 nm, PDI value was in the range of 0.2−0.3, and had no visual physical instability as they kept stable for 28 days at 4 °C. Lipid nanoemulsions were also produced with esters of myristic acid and ASE + BNO. These fatty acid esters significantly influenced the particle size of nanoemulsions. For instance, methyl tetradecanoate led to the smallest particle size nanoemulsions (124 nm), homogeneous size distribution, and high physical stability under 4 and 32 °C for 28 days. This work demonstrates that the chemical composition of vegetable oils and myristic acid esters, the storage temperature, the chain length of fatty acid esters (FAE), and their use as co-lipids improve the physical stability of lipid nanoemulsions and nanoparticles from annatto seed oily extract.
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Affiliation(s)
- Sônia do Socorro do C. Oliveira
- Laboratório de Biocatálise e Síntese Orgânica Aplicada, Departamento de Ciências Exatas, Universidade Federal do Amapá, Rod. JK, KM 02, Macapa 68902-280, Brazil
- Instituto de Pesquisas Científicas e Tecnológicas do Estado do Amapá, Macapa 68901-025, Brazil
| | - Edmilson dos S. Sarmento
- Laboratório de Biocatálise e Síntese Orgânica Aplicada, Departamento de Ciências Exatas, Universidade Federal do Amapá, Rod. JK, KM 02, Macapa 68902-280, Brazil
| | - Victor H. Marinho
- Laboratório de Biocatálise e Síntese Orgânica Aplicada, Departamento de Ciências Exatas, Universidade Federal do Amapá, Rod. JK, KM 02, Macapa 68902-280, Brazil
| | - Rayanne R. Pereira
- Laboratório de Biocatálise e Síntese Orgânica Aplicada, Departamento de Ciências Exatas, Universidade Federal do Amapá, Rod. JK, KM 02, Macapa 68902-280, Brazil
| | - Luis P. Fonseca
- Departamento de Bioengenharia, Institute for Bioengineering and Biosciences (iBB), Instituto Superior Técnico (IST), Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisbon, Portugal
- Correspondence: (L.P.F.); (I.M.F.)
| | - Irlon M. Ferreira
- Laboratório de Biocatálise e Síntese Orgânica Aplicada, Departamento de Ciências Exatas, Universidade Federal do Amapá, Rod. JK, KM 02, Macapa 68902-280, Brazil
- Correspondence: (L.P.F.); (I.M.F.)
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Gładkowski W, Włoch A, Pruchnik H, Chojnacka A, Grudniewska A, Wysota A, Dunal A, Rubiano Castro D, Rudzińska M. Acylglycerols of Myristic Acid as New Candidates for Effective Stigmasterol Delivery-Design, Synthesis, and the Influence on Physicochemical Properties of Liposomes. Molecules 2022; 27:molecules27113406. [PMID: 35684341 PMCID: PMC9182174 DOI: 10.3390/molecules27113406] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 05/17/2022] [Accepted: 05/23/2022] [Indexed: 11/30/2022] Open
Abstract
New carriers of phytosterols; acylglycerols containing natural myristic acid at sn-1 and sn-3 positions and stigmasterol residue linked to sn-2 position by carbonate and succinate linker have been designed and synthesized in three-step synthesis from dihydroxyacetone (DHA). The synthetic pathway involved Steglich esterification of DHA with myristic acid; reduction of carbonyl group of 1,3-dimyristoylpropanone and esterification of 1,3-dimyristoylglicerol with stigmasterol chloroformate or stigmasterol hemisuccinate. The structure of the obtained hybrids was established by the spectroscopic methods (NMR; IR; HRMS). Obtained hybrid molecules were used to form new liposomes in the mixture with model phospholipid and their effect on their physicochemical properties was determined, including the polarity, fluidity, and main phase transition of liposomes using differential scanning calorimetry and fluorimetric methods. The results confirm the significant effect of both stigmasterol-containing acylglycerols on the hydrophilic and hydrophobic region of liposome membranes. They significantly increase the order in the polar heads of the lipid bilayer and increase the rigidity in the hydrophobic region. Moreover, the presence of both acylglycerols in the membranes shifts the temperature of the main phase transition towards higher temperatures. Our results indicate stabilization of the bilayer over a wide temperature range (above and below the phase transition temperature), which in addition to the beneficial effects of phytosterols on human health makes them more attractive components of novel lipid nanocarriers compared to cholesterol.
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Affiliation(s)
- Witold Gładkowski
- Department of Food Chemistry and Biocatalysis, Wrocław University of Environmental and Life Sciences, Norwida 25, 50-375 Wrocław, Poland; (A.C.); (A.G.); (A.W.)
- Correspondence: (W.G.); (A.W.); (A.D.); Tel.: +48-71-3205-154 (W.G.); +48-71-3205-461 (A.W.); +48-724-540-245 (A.D.)
| | - Aleksandra Włoch
- Department of Physics and Biophysics, Wrocław University of Environmental and Life Sciences, Norwida 25, 50-375 Wrocław, Poland;
- Correspondence: (W.G.); (A.W.); (A.D.); Tel.: +48-71-3205-154 (W.G.); +48-71-3205-461 (A.W.); +48-724-540-245 (A.D.)
| | - Hanna Pruchnik
- Department of Physics and Biophysics, Wrocław University of Environmental and Life Sciences, Norwida 25, 50-375 Wrocław, Poland;
| | - Anna Chojnacka
- Department of Food Chemistry and Biocatalysis, Wrocław University of Environmental and Life Sciences, Norwida 25, 50-375 Wrocław, Poland; (A.C.); (A.G.); (A.W.)
| | - Aleksandra Grudniewska
- Department of Food Chemistry and Biocatalysis, Wrocław University of Environmental and Life Sciences, Norwida 25, 50-375 Wrocław, Poland; (A.C.); (A.G.); (A.W.)
| | - Agnieszka Wysota
- Department of Food Chemistry and Biocatalysis, Wrocław University of Environmental and Life Sciences, Norwida 25, 50-375 Wrocław, Poland; (A.C.); (A.G.); (A.W.)
| | - Anna Dunal
- Department of Food Chemistry and Biocatalysis, Wrocław University of Environmental and Life Sciences, Norwida 25, 50-375 Wrocław, Poland; (A.C.); (A.G.); (A.W.)
- Correspondence: (W.G.); (A.W.); (A.D.); Tel.: +48-71-3205-154 (W.G.); +48-71-3205-461 (A.W.); +48-724-540-245 (A.D.)
| | - Daniel Rubiano Castro
- Facultat de Biologia, Universitat de Barcelona, Avinguda de Diagonal 643, 08007 Barcelona, Spain;
| | - Magdalena Rudzińska
- Faculty of Food Science and Nutrition, Poznań University of Life Sciences, 60-637 Poznań, Poland;
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Saraswathi V, Kumar N, Ai W, Gopal T, Bhatt S, Harris EN, Talmon GA, Desouza CV. Myristic Acid Supplementation Aggravates High Fat Diet-Induced Adipose Inflammation and Systemic Insulin Resistance in Mice. Biomolecules 2022; 12:739. [PMID: 35740864 PMCID: PMC9220168 DOI: 10.3390/biom12060739] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Revised: 05/19/2022] [Accepted: 05/20/2022] [Indexed: 12/12/2022] Open
Abstract
Saturated fatty acids (SFAs) are considered to be detrimental to human health. One of the SFAs, myristic acid (MA), is known to exert a hypercholesterolemic effect in mice as well as humans. However, its effects on altering adipose tissue (AT) inflammation and systemic insulin resistance (IR) in obesity are still unclear. Here, we sought to determine the effects of a high fat (HF) diet supplemented with MA on obesity-associated metabolic disorders in mice. Wild-type C57BL/6 mice were fed a HF diet in the presence or absence of 3% MA for 12 weeks. Plasma lipids, plasma adipokines, AT inflammation, systemic IR, glucose homeostasis, and hepatic steatosis were assessed. The body weight and visceral adipose tissue (VAT) mass were significantly higher in mice receiving the HF+MA diet compared to HF diet-fed controls. Plasma total cholesterol levels were marginally increased in HF+MA-fed mice compared to controls. Fasting blood glucose was comparable between HF and HF+MA-fed mice. Interestingly, the plasma insulin and HOMA-IR index, a measure of insulin resistance, were significantly higher in HF+MA-fed mice compared to HF controls. Macrophage and inflammatory markers were significantly elevated in the AT and AT-derived stromal vascular cells upon MA feeding. Moreover, the level of circulating resistin, an adipokine promoting insulin resistance, was significantly higher in HF+MA-fed mice compared with HF controls. The insulin tolerance test revealed that the IR was higher in mice receiving the MA supplementation compared to HF controls. Moreover, the glucose tolerance test showed impairment in systemic glucose homeostasis in MA-fed mice. Analyses of liver samples showed a trend towards an increase in liver TG upon MA feeding. However, markers of oxidative stress and inflammation were reduced in the liver of mice fed an MA diet compared to controls. Taken together, our data suggest that chronic administration of MA in diet exacerbates obesity-associated insulin resistance and this effect is mediated in part, via increased AT inflammation and increased secretion of resistin.
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Affiliation(s)
- Viswanathan Saraswathi
- Division of Diabetes, Endocrinology, and Metabolism, Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA; (N.K.); (W.A.); (T.G.); (S.B.); (C.V.D.)
- Research Service, VA Nebraska-Western Iowa Health Care System, Omaha, NE 68105, USA
| | - Narendra Kumar
- Division of Diabetes, Endocrinology, and Metabolism, Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA; (N.K.); (W.A.); (T.G.); (S.B.); (C.V.D.)
- Research Service, VA Nebraska-Western Iowa Health Care System, Omaha, NE 68105, USA
| | - Weilun Ai
- Division of Diabetes, Endocrinology, and Metabolism, Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA; (N.K.); (W.A.); (T.G.); (S.B.); (C.V.D.)
- Research Service, VA Nebraska-Western Iowa Health Care System, Omaha, NE 68105, USA
| | - Thiyagarajan Gopal
- Division of Diabetes, Endocrinology, and Metabolism, Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA; (N.K.); (W.A.); (T.G.); (S.B.); (C.V.D.)
- Research Service, VA Nebraska-Western Iowa Health Care System, Omaha, NE 68105, USA
| | - Saumya Bhatt
- Division of Diabetes, Endocrinology, and Metabolism, Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA; (N.K.); (W.A.); (T.G.); (S.B.); (C.V.D.)
- Research Service, VA Nebraska-Western Iowa Health Care System, Omaha, NE 68105, USA
| | - Edward N. Harris
- Department of Biochemistry, University of Nebraska, Lincoln, NE 68588, USA;
| | - Geoffrey A. Talmon
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE 68198, USA;
| | - Cyrus V. Desouza
- Division of Diabetes, Endocrinology, and Metabolism, Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA; (N.K.); (W.A.); (T.G.); (S.B.); (C.V.D.)
- Research Service, VA Nebraska-Western Iowa Health Care System, Omaha, NE 68105, USA
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11
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Zhu Y. Road to the discovery of HO-2's myristate binding activity. Cell Host Microbe 2022; 30:483-484. [PMID: 35421349 DOI: 10.1016/j.chom.2022.03.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We discovered an unexpected new activity of a well-studied enzyme, heme oxygenase 2 (HO-2)-proof that an old dog can learn new tricks.
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Affiliation(s)
- Yiping Zhu
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, USA.
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12
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Rillig MC, Aguilar-Trigueros CA, Anderson IC, Antonovics J, Ballhausen MB, Bergmann J, Bielcik M, Chaudhary VB, Deveautour C, Grünfeld L, Hempel S, Lakovic M, Lammel DR, Lehmann A, Lehmann J, Leifheit EF, Liang Y, Li E, Lozano YM, Manntschke A, Mansour I, Oviatt P, Pinek L, Powell JR, Roy J, Ryo M, Sosa-Hernández MA, Veresoglou SD, Wang D, Yang G, Zhang H. Myristate and the ecology of AM fungi: significance, opportunities, applications and challenges. New Phytol 2020; 227:1610-1614. [PMID: 32147825 DOI: 10.1111/nph.16527] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Accepted: 02/27/2020] [Indexed: 06/10/2023]
Abstract
A recent study by Sugiura and coworkers reported the non-symbiotic growth and spore production of an arbuscular mycorrhizal (AM) fungus, Rhizophagus irregularis, when the fungus received an external supply of certain fatty acids, myristates (C:14). This discovery follows the insight that AM fungi receive fatty acids from their hosts when in symbiosis. If this result holds up and can be repeated under nonsterile conditions and with a broader range of fungi, it has numerous consequences for our understanding of AM fungal ecology, from the level of the fungus, at the plant community level, and to functional consequences in ecosystems. In addition, myristate may open up several avenues from a more applied perspective, including improved fungal culture and supplementation of AM fungi or inoculum in the field. We here map these potential opportunities, and additionally offer thoughts on potential risks of this potentially new technology. Lastly, we discuss the specific research challenges that need to be overcome to come to an understanding of the potential role of myristate in AM ecology.
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Affiliation(s)
- Matthias C Rillig
- Institut für Biologie, Freie Universität Berlin, Altensteinstr. 6, D-14195, Berlin, Germany
- Berlin-Brandenburg Institute of Advanced Biodiversity Research, D-14195, Berlin, Germany
| | - Carlos A Aguilar-Trigueros
- Institut für Biologie, Freie Universität Berlin, Altensteinstr. 6, D-14195, Berlin, Germany
- Berlin-Brandenburg Institute of Advanced Biodiversity Research, D-14195, Berlin, Germany
| | - Ian C Anderson
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, 2751, Australia
| | - Janis Antonovics
- Department of Biology, University of Virginia, Charlottesville, VA, 22904, USA
| | - Max-Bernhard Ballhausen
- Institut für Biologie, Freie Universität Berlin, Altensteinstr. 6, D-14195, Berlin, Germany
- Berlin-Brandenburg Institute of Advanced Biodiversity Research, D-14195, Berlin, Germany
| | - Joana Bergmann
- Institut für Biologie, Freie Universität Berlin, Altensteinstr. 6, D-14195, Berlin, Germany
- Berlin-Brandenburg Institute of Advanced Biodiversity Research, D-14195, Berlin, Germany
| | - Milos Bielcik
- Institut für Biologie, Freie Universität Berlin, Altensteinstr. 6, D-14195, Berlin, Germany
- Berlin-Brandenburg Institute of Advanced Biodiversity Research, D-14195, Berlin, Germany
| | - V Bala Chaudhary
- Department of Environmental Science and Studies, DePaul University, Chicago, IL, 60614, USA
| | - Coline Deveautour
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, 2751, Australia
- National University of Ireland, University Road, Galway, H91 TK33, Ireland
- Environment, Soils and Land-Use Department, Teagasc, Johnstown Castle, Y35 Y521, Co. Wexford, Ireland
| | - Leonie Grünfeld
- Institut für Biologie, Freie Universität Berlin, Altensteinstr. 6, D-14195, Berlin, Germany
- Berlin-Brandenburg Institute of Advanced Biodiversity Research, D-14195, Berlin, Germany
| | - Stefan Hempel
- Institut für Biologie, Freie Universität Berlin, Altensteinstr. 6, D-14195, Berlin, Germany
- Berlin-Brandenburg Institute of Advanced Biodiversity Research, D-14195, Berlin, Germany
| | - Milica Lakovic
- Institut für Biologie, Freie Universität Berlin, Altensteinstr. 6, D-14195, Berlin, Germany
- Berlin-Brandenburg Institute of Advanced Biodiversity Research, D-14195, Berlin, Germany
| | - Daniel R Lammel
- Institut für Biologie, Freie Universität Berlin, Altensteinstr. 6, D-14195, Berlin, Germany
- Berlin-Brandenburg Institute of Advanced Biodiversity Research, D-14195, Berlin, Germany
| | - Anika Lehmann
- Institut für Biologie, Freie Universität Berlin, Altensteinstr. 6, D-14195, Berlin, Germany
- Berlin-Brandenburg Institute of Advanced Biodiversity Research, D-14195, Berlin, Germany
| | - Johannes Lehmann
- School of Integrative Plant Science, Cornell University, Ithaca, NY, 14853, USA
- Atkinson Center for a Sustainable Future, Cornell University, Ithaca, NY, 14853, USA
| | - Eva F Leifheit
- Institut für Biologie, Freie Universität Berlin, Altensteinstr. 6, D-14195, Berlin, Germany
- Berlin-Brandenburg Institute of Advanced Biodiversity Research, D-14195, Berlin, Germany
| | - Yun Liang
- Institut für Biologie, Freie Universität Berlin, Altensteinstr. 6, D-14195, Berlin, Germany
- Berlin-Brandenburg Institute of Advanced Biodiversity Research, D-14195, Berlin, Germany
| | - Erqin Li
- Institut für Biologie, Freie Universität Berlin, Altensteinstr. 6, D-14195, Berlin, Germany
- Berlin-Brandenburg Institute of Advanced Biodiversity Research, D-14195, Berlin, Germany
| | - Yudi M Lozano
- Institut für Biologie, Freie Universität Berlin, Altensteinstr. 6, D-14195, Berlin, Germany
- Berlin-Brandenburg Institute of Advanced Biodiversity Research, D-14195, Berlin, Germany
| | - Annette Manntschke
- Institut für Biologie, Freie Universität Berlin, Altensteinstr. 6, D-14195, Berlin, Germany
- Berlin-Brandenburg Institute of Advanced Biodiversity Research, D-14195, Berlin, Germany
| | - India Mansour
- Institut für Biologie, Freie Universität Berlin, Altensteinstr. 6, D-14195, Berlin, Germany
- Berlin-Brandenburg Institute of Advanced Biodiversity Research, D-14195, Berlin, Germany
| | - Peter Oviatt
- Program in History, Anthropology and Science and Technology Studies, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Liliana Pinek
- Institut für Biologie, Freie Universität Berlin, Altensteinstr. 6, D-14195, Berlin, Germany
- Berlin-Brandenburg Institute of Advanced Biodiversity Research, D-14195, Berlin, Germany
| | - Jeff R Powell
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, 2751, Australia
| | - Julien Roy
- Institut für Biologie, Freie Universität Berlin, Altensteinstr. 6, D-14195, Berlin, Germany
- Berlin-Brandenburg Institute of Advanced Biodiversity Research, D-14195, Berlin, Germany
| | - Masahiro Ryo
- Institut für Biologie, Freie Universität Berlin, Altensteinstr. 6, D-14195, Berlin, Germany
- Berlin-Brandenburg Institute of Advanced Biodiversity Research, D-14195, Berlin, Germany
| | - Moisés A Sosa-Hernández
- Institut für Biologie, Freie Universität Berlin, Altensteinstr. 6, D-14195, Berlin, Germany
- Berlin-Brandenburg Institute of Advanced Biodiversity Research, D-14195, Berlin, Germany
| | - Stavros D Veresoglou
- Institut für Biologie, Freie Universität Berlin, Altensteinstr. 6, D-14195, Berlin, Germany
- Berlin-Brandenburg Institute of Advanced Biodiversity Research, D-14195, Berlin, Germany
| | - Dongwei Wang
- Institut für Biologie, Freie Universität Berlin, Altensteinstr. 6, D-14195, Berlin, Germany
- Berlin-Brandenburg Institute of Advanced Biodiversity Research, D-14195, Berlin, Germany
| | - Gaowen Yang
- Institut für Biologie, Freie Universität Berlin, Altensteinstr. 6, D-14195, Berlin, Germany
- Berlin-Brandenburg Institute of Advanced Biodiversity Research, D-14195, Berlin, Germany
| | - Haiyang Zhang
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, 2751, Australia
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13
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García-Pelayo MC, García-Peregrín E, Martínez-Cayuela M. Differential Translational Effects of Myristic Acid and Eicosapentaenoic Acid on 3-Hydroxy-3-Methylglutaryl-CoA Reductase From Reuber H35 Hepatoma Cells. Exp Biol Med (Maywood) 2016; 229:781-6. [PMID: 15337832 DOI: 10.1177/153537020422900810] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The mechanisms by which saturated and polyunsaturated fatty acids may exert their effects on levels of blood cholesterol and human atherosclerosis have not been fully established. In this work, we studied the translational effects of myristic (14:0) and eicosapentaenoic (20:5) acids on 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase from Reuber H35 hepatoma cells. This enzyme is an intrinsic membrane, 96-kDa protein whose proteolysis releases an enzymatically active, 52- to 56-kDa, soluble fragment. We optimized an immunoblot procedure for quantifying small amounts of both the native and the soluble forms of HMG-CoA reductase from Reuber H35 hepatoma cells. We demonstrated that the upregulation of HMG-CoA reductase by myristic acid is due to an increase of the HMG-CoA reductase protein; therefore, protein synthesis would be required for the increase of HMG-CoA reductase activity caused by this fatty acid. In contrast, the downregulation of HMG-CoA reductase caused by eicosapentaenoic acid is not due to decreased protein synthesis, since similar levels of protein were found in the presence and absence of this fatty acid. Results obtained with cycloheximide as a protein-synthesis inhibitor confirm these findings.
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Affiliation(s)
- M Carmen García-Pelayo
- Department of Biochemistry and Molecular Biology, University of Granada, Polígono de Cartuja s/n, 18071 Granada, Spain
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14
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Hadrévi J, Ghafouri B, Sjörs A, Antti H, Larsson B, Crenshaw AG, Gerdle B, Hellström F. Comparative metabolomics of muscle interstitium fluid in human trapezius myalgia: an in vivo microdialysis study. Eur J Appl Physiol 2014; 113:2977-89. [PMID: 24078209 PMCID: PMC3828502 DOI: 10.1007/s00421-013-2716-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Accepted: 08/23/2013] [Indexed: 02/02/2023]
Abstract
Purpose The mechanisms behind trapezius myalgia are unclear. Many hypotheses have been presented suggesting an altered metabolism in the muscle. Here, muscle microdialysate from healthy and myalgic muscle is analysed using metabolomics. Metabolomics analyse a vast number of metabolites, enabling a comprehensive explorative screening of the cellular processes in the muscle. Methods Microdialysate samples were obtained from the shoulder muscle of healthy and myalgic subjects that performed a work and stress test. Samples from the baseline period and from the recovery period were analysed using gas chromatography—mass spectrometry (GC–MS) together with multivariate analysis to detect differences in extracellular content of metabolites between groups. Systematic differences in metabolites between groups were identified using multivariate analysis and orthogonal partial least square discriminate analysis (OPLS-DA). A complementary Mann–Whitney U test of group difference in individual metabolites was also performed. Results A large number of metabolites were detected and identified in this screening study. At baseline, no systematic differences between groups were observed according to the OPLS-DA. However, two metabolites, l-leucine and pyroglutamic acid, were significantly more abundant in the myalgic muscle compared to the healthy muscle. In the recovery period, systematic difference in metabolites between the groups was observed according to the OPLS-DA. The groups differed in amino acids, fatty acids and carbohydrates. Myristic acid and putrescine were significantly more abundant and beta-d-glucopyranose was significantly less abundant in the myalgic muscle. Conclusion This study provides important information regarding the metabolite content, thereby presenting new clues regarding the pathophysiology of the myalgic muscle.
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Affiliation(s)
- J. Hadrévi
- Section for Anatomy, Department of Integrative Medical Biology, Umeå University, 901 87 Umeå, Sweden
- Department of Occupational and Public Health Sciences, Faculty of Health and Occupational Studies, Centre for Musculoskeletal Research, University of Gävle, 907 12 Umeå, Sweden
| | - B. Ghafouri
- Rehabilitation Medicine, Department of Medicine and Health Sciences (IMH), Faculty of Health Sciences, Pain and Rehabilitation Centre, Linköping University, County Council of Östergötland, 581 85 Linköping, Sweden
- Occupational and Environmental Medicine, Department of Clinical and Experimental Medicine, Faculty of Health Sciences, Centre of Occupational and Environmental Medicine, Linköping University, County Council of Östergötland, 581 85 Linköping, Sweden
| | - A. Sjörs
- Rehabilitation Medicine, Department of Medicine and Health Sciences (IMH), Faculty of Health Sciences, Pain and Rehabilitation Centre, Linköping University, County Council of Östergötland, 581 85 Linköping, Sweden
- Institute of Stress Medicine, Carl Skottsbergs Gata 22B, 413 19 Gothenburg, Sweden
| | - H. Antti
- Department of Chemistry, Faculty of Science and Technology, Umeå University, 901 85 Umeå, Sweden
| | - B. Larsson
- Rehabilitation Medicine, Department of Medicine and Health Sciences (IMH), Faculty of Health Sciences, Pain and Rehabilitation Centre, Linköping University, County Council of Östergötland, 581 85 Linköping, Sweden
| | - A. G. Crenshaw
- Department of Occupational and Public Health Sciences, Faculty of Health and Occupational Studies, Centre for Musculoskeletal Research, University of Gävle, 907 12 Umeå, Sweden
| | - B. Gerdle
- Rehabilitation Medicine, Department of Medicine and Health Sciences (IMH), Faculty of Health Sciences, Pain and Rehabilitation Centre, Linköping University, County Council of Östergötland, 581 85 Linköping, Sweden
| | - F. Hellström
- Department of Occupational and Public Health Sciences, Faculty of Health and Occupational Studies, Centre for Musculoskeletal Research, University of Gävle, 907 12 Umeå, Sweden
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15
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Pignatello R, Noce C, Campisi A, Acquaviva R, Bucolo C, Puglisi G, Toth I. Evaluation of cell tolerability of a series of lipoamino acids using biological membranes and a biomembrane model. Curr Drug Deliv 2007; 4:109-21. [PMID: 17456030 DOI: 10.2174/156720107780362348] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The interaction of a series of amphiphilic 2-alkyl aminoacids (lipoamino acids, LAAs) with different cell cultures and biomembrane models was investigated. LAAs can be useful promoieties to modify the physico-chemical properties of many drugs, and in particular their lipophilicity. Tests were performed in vitro on mammalian cells (murine astrocytes) and human red blood cells (haemolysis), and in vivo on rabbit eye as alternative models to assess the tolerability or the potential damaging effects of these compounds on different biological systems. The mode of interaction of LAAs with pure phospholipid multilamellar liposomes, taken as a biomembrane model, was also analysed by differential scanning calorimetry experiments. Different tolerability/toxicity patterns were obtained in the various models; in particular, the most lipophilic terms of the series, methyl 2-aminohexadecanoate (LAA16), displayed haemolytic activity and toxicity for mouse astrocyte cultures. A specific assay confirmed that LAA16 acted at level of cell membranes, while neither any damaging effects on nucleus or apoptotic induction were observed. The shorter-chain LAAs and the tetradecyl homologue (LAA14) showed the best compatibility with the various cell models.
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Affiliation(s)
- R Pignatello
- Department of Pharmaceutical Sciences, University of Catania, Catania, Italy.
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16
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Affiliation(s)
- D A Rudnick
- Department of Molecular Biology and Pharmacology, Washington University School of Medicine, St. Louis, MO
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17
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Abstract
The ability of solutions of tripotassium phosphate (TPP) and fatty acids (lauric and myristic acids) to reduce populations of spoilage and pathogenic microorganisms associated with processed poultry was examined. In vitro studies were conducted with cultures of bacteria (Campylobacter jejuni, Escherichia coli, Listeria monocytogenes, Pseudomonas aeruginosa, Salmonella Typhimurium, and Staphylococcus aureus) and yeasts (Candida ernobii and Yarrowia lipolytica). Cultures of the bacteria and yeasts were suspended in solutions of TPP or mixtures of TPP with lauric or myristic acid and mixed for 5 min. Viable numbers (log CFU per milliliter) in the suspensions were enumerated on microbiological agar. Results indicated that TPP solutions are highly bactericidal toward gram-negative bacteria and that mixtures of TPP and fatty acids are highly microbicidal toward gram-negative bacteria, gram-positive bacteria, and yeasts. The microbicidal activity of mixtures of TPP and fatty acids toward the native bacterial flora of skin of processed broiler carcasses was also examined. Skin samples were washed in mixtures of TPP and fatty acid, and the populations of total aerobic bacteria, campylobacters, enterococci, E. coli, lactic acid bacteria, pseudomonads, staphylococci, and yeasts in the skin rinsates were enumerated on the appropriate microbiological media. Results indicated that washing the skin in mixtures of TPP and fatty acids produced significant reductions in the number of aerobic bacteria, campylobacters, E. coli, pseudomonads, and yeasts recovered from skin rinsates, but there was no significant reduction in the populations of enterococci, lactic acid bacteria, or staphylococci. These findings indicate that mixtures of TPP and fatty acids possess microbicidal activity against several microorganisms associated with processed poultry and that these solutions could be useful as microbicides to reduce the populations of some bacteria and yeasts associated with some poultry processing operations.
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Affiliation(s)
- Arthur Hinton
- Poultry Processing and Meat Quality Research Unit, Agricultural Research Service, US Department of Agriculture, 950 College Station Road, Russell Research Center, Athens, Georgia 30605, USA.
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Dawe S, Corcoran JA, Clancy EK, Salsman J, Duncan R. Unusual topological arrangement of structural motifs in the baboon reovirus fusion-associated small transmembrane protein. J Virol 2005; 79:6216-26. [PMID: 15858006 PMCID: PMC1091723 DOI: 10.1128/jvi.79.10.6216-6226.2005] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Select members of the Reoviridae are the only nonenveloped viruses known to induce syncytium formation. The fusogenic orthoreoviruses accomplish cell-cell fusion through a distinct class of membrane fusion-inducing proteins referred to as the fusion-associated small transmembrane (FAST) proteins. The p15 membrane fusion protein of baboon reovirus is unique among the FAST proteins in that it contains two hydrophobic regions (H1 and H2) recognized as potential transmembrane (TM) domains, suggesting a polytopic topology. However, detailed topological analysis of p15 indicated only the H1 domain is membrane spanning. In the absence of an N-terminal signal peptide, the H1 TM domain serves as a reverse signal-anchor to direct p15 membrane insertion and a bitopic N(exoplasmic)/C(cytoplasmic) topology. This topology results in the translocation of the smallest ectodomain ( approximately 20 residues) of any known viral fusion protein, with the majority of p15 positioned on the cytosolic side of the membrane. Mutagenic analysis indicated the unusual presence of an N-terminal myristic acid on the small p15 ectodomain is essential to the fusion process. Furthermore, the only other hydrophobic region (H2) present in p15, aside from the TM domain, is located within the endodomain. Consequently, the p15 ectodomain is devoid of a fusion peptide motif, a hallmark feature of membrane fusion proteins. The exceedingly small, myristoylated ectodomain and the unusual topological distribution of structural motifs in this nonenveloped virus membrane fusion protein necessitate alternate models of protein-mediated membrane fusion.
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Affiliation(s)
- Sandra Dawe
- Department of Microbiology and Immunology, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada.
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19
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Matsubara M. [Structures and molecular recognition of MARCKS family proteins]. Seikagaku 2005; 77:50-5. [PMID: 15770953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
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20
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Ganesan LP, Wei G, Pengal RA, Moldovan L, Moldovan N, Ostrowski MC, Tridandapani S. The Serine/Threonine Kinase Akt Promotes Fcγ Receptor-mediated Phagocytosis in Murine Macrophages through the Activation of p70S6 Kinase. J Biol Chem 2004; 279:54416-25. [PMID: 15485887 DOI: 10.1074/jbc.m408188200] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Fc gamma receptor (Fc gamma R) clustering by immune complexes activates multiple signaling pathways leading to phagocytosis. We and others have previously reported that Akt is phosphorylated in response to Fc gamma R clustering. However, the functional consequence of Akt activation by Fc gamma R is not known. Using Raw 264.7 macrophage cells transfected to overexpress either constitutively active myristoylated (Myr)-Akt or a dominant-negative CAAX-Akt and bone marrow macrophages (BMMs) from wild-type and transgenic mice expressing macrophage-specific Myr-Akt, we analyzed the function of Akt in phagocytosis. We report that overexpression of Myr-Akt resulted in significant increase in phagocytic efficiency, whereas CAAX-Akt down-regulated phagocytosis in Raw 264.7 cells. Likewise BMMs expressing Myr-Akt displayed enhanced phagocytic ability. Analyzing the downstream effectors of Akt, we demonstrate that p70S6 kinase is constitutively phosphorylated in Myr-Akt-expressing BMMs. p70S6 kinase is reported to influence actin cytoskeleton and cell migration, suggesting that Akt may influence phagocytosis through the activation of p70S6 kinase. Consistent with this, overexpression of either wild-type or constitutively active but not a kinase-inactive p70S6 kinase in Raw 264.7 cells significantly enhanced phagocytosis. Likewise suppression of p70S6 kinase with rapamycin down-regulated phagocytic efficiency conferred by the expression of constitutively active Akt. These findings demonstrate a novel role for Akt in phagocytosis through the activation of p70S6 kinase.
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Affiliation(s)
- Latha P Ganesan
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, The Ohio State University, Columbus, Ohio 43210, USA
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21
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Pinto APA, Campana PT, Beltramini LM, Silber AM, Araújo APU. Structural characterization of a recombinant flagellar calcium-binding protein from Trypanosoma cruzi. Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics 2003; 1652:107-14. [PMID: 14644046 DOI: 10.1016/j.bbapap.2003.08.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Calflagin are flagellar calcium-binding proteins belonging to the EF-hand super family described in several protozoa, including Trypanosoma cruzi. Evidences have shown that Ca(2+) may play an important regulatory role in trypanosomatid flagellar mobility. In these parasites, the response of the cell to variations of Ca(2+) levels is determined by a variety of calcium-modulated proteins. Starting from T. cruzi cDNA lambdagt11 library trypomastigote, a clone encoding a 29-kDa flagellar protein designated recombinant calflagin (rC29) was selected. rC29 is a calcium-acyl switch protein modified by the addition of myristate and palmitate at its amino terminal segment. In this work, unmyristoylated rC29 was expressed in Escherichia coli as an intein fusion protein and purified by affinity chromatography. Circular dichroism (CD) and fluorescence measurements showed conformational changes of rC29 due to Ca(2+) binding. The Ca(2+) binding constants were obtained by tryptophan intrinsic fluorescence spectroscopy. Fluorescence titration exhibited two classes of Ca(2+)-binding sites in the unmyristoylated rC29, which bind calcium with apparent association constant of K(a) of 3.3+/-0.5 (10(6)) and 1.9+/-0.2 (10(4)) M(-1). Experiment using 8-anilinonaphthalene-1-sulfonic acid (ANS) as hydrophobic probe showed that the Ca(2+)-loaded form of rC29 contains exposed hydrophobic surfaces, thus suggesting that rC29 is probably functioning as a calcium sensor.
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Affiliation(s)
- Andressa P A Pinto
- Programa de Pós-graduação em Genética e Evolução, Universidade Federal de São Carlos, Rodovia Washington Luiz, km 235, São Carlos, São Paulo, Brazil
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22
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Matsunaga I, Sumimoto T, Ayata M, Ogura H. Functional modulation of a peroxygenase cytochrome P450: novel insight into the mechanisms of peroxygenase and peroxidase enzymes. FEBS Lett 2002; 528:90-4. [PMID: 12297285 DOI: 10.1016/s0014-5793(02)03261-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Cytochrome P450(BSbeta) is a peroxygenase that catalyzes the alpha- or beta-hydroxylation of myristic acid by utilizing H(2)O(2). The wild-type enzyme not only hydroxylated myristic acid, but oxidized 3,5,3',5'-tetramethylbenzidine (TMB), a peroxidase substrate, in a myristic acid-dependent reaction. Study of inhibition of hydroxylation of myristic acid by TMB indicates these two substrates compete for the same highly reactive intermediate during the course of their respective reactions. When deuterated myristic acid was used as a substrate to decrease hydroxylation activity, the rate of TMB oxidation increased. This increased rate of TMB oxidation was greatly enhanced when the R242K mutant enzyme bound with deuterated myristic acid was used. These results suggest that there are critical structural elements at the distal active site which determine whether this enzyme acts as a peroxygenase or a peroxidase.
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Affiliation(s)
- Isamu Matsunaga
- Department of Virology, Osaka City University Medical School, 1-4-3 Asahi-machi, Abeno-ku, Japan.
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23
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Chiu HC, Yao SY, Wang CT. Coding sequences upstream of the human immunodeficiency virus type 1 reverse transcriptase domain in Gag-Pol are not essential for incorporation of the Pr160(gag-pol) into virus particles. J Virol 2002; 76:3221-31. [PMID: 11884546 PMCID: PMC136043 DOI: 10.1128/jvi.76.7.3221-3231.2002] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Incorporation of the human immunodeficiency virus type 1 (HIV-1) Gag-Pol into virions is thought to be mediated by the N-terminal Gag domain via interaction with the Gag precursor. However, one recent study has demonstrated that the murine leukemia virus Pol can be incorporated into virions independently of Gag-Pol expression, implying a possible interaction between the Pol and Gag precursor. To test whether the HIV-1 Pol can be incorporated into virions on removal of the N-terminal Gag domain and to define sequences required for the incorporation of Gag-Pol into virions in more detail, a series of HIV Gag-Pol expression plasmids with various extensive deletions in the region upstream of the reverse transcriptase (RT) domain was constructed, and viral incorporation of the Gag-Pol deletion mutants was examined by cotransfecting 293T cells with a plasmid expressing Pr55(gag). Analysis indicated that deletion of the N-terminal two-thirds of the gag coding region did not significantly affect the incorporation of Gag-Pol into virions. In contrast, Gag-Pol proteins with deletions covering the capsid (CA) major homology regions and the adjacent C-terminal CA regions were impaired with respect to assembly into virions. However, Gag-Pol with sequences deleted upstream of the protease, or of the RT domain but retaining 15 N-terminal gag codons, could still be rescued into virions at a level about 20% of the wild-type level. When assayed in a nonmyristylated Gag-Pol context, all of the Gag-Pol deletion mutants were incorporated into virions at a level comparable to their myristylated counterparts, suggesting that the incorporation of the Gag-Pol deletion mutants into virions is independent of the N-terminal myristylation signal.
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Affiliation(s)
- Hsu-Chen Chiu
- Institute of Clinical Medicine, National Yang-Ming University School of Medicine, Department of Medical Research and Education, Taipei Veterans General Hospital, Taiwan
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24
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Abstract
Different assay technologies are available that allow ligand occupancy of G protein coupled receptors to be converted into robust functional assay signals. Of particular interest are universal screening systems such that activation of any GPCR can be detected with a common assay end point. The promiscuous G protein Galpha16 and chimeric G proteins are broadly used tools for setting up almost universal assay systems. Many efforts focused on making G proteins more promiscuous, however no attempts have been made to make promiscuos G proteins more sensitive by interfering with their cellular protein distribution. As a model system, we used a promiscuous G protein alphaq subunit, that lacks the highly conserved six amino acid N-terminal extension and bears four residues of alphai sequence at its C-terminus replacing the corresponding alphaq sequence (referred to as delta6qi4). When expressed in COS7 cells, delta6qi4 undergoes palmitoylation at its N-terminus. Cell fractionation and immunoblotting analysis indicated localization in the particulate and cytosolic fraction. Interestingly, introduction of a consensus site for N-terminal myristoylation (the resulting mutant referred to as delta6qi4myr) created a protein that was dually acylated and exclusively located in the particulate fraction. As a measure of G protein activation delta6qi4 and delta6qi4myr were coexpressed (in CHO cells) with a series of different Gi/o coupled receptors and ligand induced increases in intracellular Ca2+ release were determined with the FLIPR technology (Fluorescence plate imaging reader from Molecular Devices Corp.). All of the receptors interacted more efficiently with delta6qi4myr as compared with delta6qi4. It could be shown that increased functional responses of agonist activated GPCRs are due to the higher content of delta6qi4myr in the plasma membrane. Our results indicate that manipulation of subcellular localization of G protein alpha subunits-moving them from the cytosol to the plasma membrane-potentiates signaling of agonist activated GPCRs. It is concluded that addition of myristoylation sites into otherwise exclusively palmitoylated G proteins is a new and sensitive approach and may be applicable when functional assays are expected to yield weak signals as is the case when screening extracts of tissues for biologically active GPCR ligands.
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Affiliation(s)
- Evi Kostenis
- Aventis Pharma, Disease Group Cardiovascular, H825, 3rd Floor, Rm. 354, D-65926 Frankfurt, Germany.
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25
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Abstract
The fibroblast growth factor receptor (FGFR) family members mediate a number of important cellular processes, and are mutated or overexpressed in several forms of human cancer. Mutation of Lys650-->Glu in the activation loop of the FGFR3 kinase domain causes the lethal human skeletal disorder thanatophoric dysplasia type II (TDII) and is also found in patients with multiple myeloma, bladder and cervical carcinomas. This mutation leads to constitutive activation of FGFR3. To compare the signaling activity of FGFR family members, this activating mutation was generated in FGFR1, FGFR3, and FGFR4. We show that the kinase domains of FGFR1, FGFR3, and FGFR4 containing the activation loop mutation, when targeted to the plasma membrane by a myristylation signal, can transform NIH3T3 cells and induce neurite outgrowth in PC12 cells. Phosphorylation of Shp2, PLC-gamma, and MAPK was also stimulated by all three 'TDII-like' FGFR derivatives. Additionally, activation of Stat1 and Stat3 was observed in cells expressing the activated FGFR derivatives. Finally, we demonstrate that FGFR1, FGFR3, and FGFR4 derivatives can stimulate PI-3 kinase activity. Our comparison of these activated receptor derivatives reveals a significant overlap in the panel of effector proteins used to mediate downstream signals. This also represents the first demonstration that activation of FGFR4, in addition to FGFR1 and FGFR3, can induce cellular transformation. Moreover, our results suggest that Stat activation by FGFRs is important in their ability to act as oncogenes.
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MESH Headings
- 3T3 Cells
- Amino Acid Sequence
- Animals
- Cell Division
- Cell Line, Transformed
- Cell Transformation, Neoplastic
- DNA-Binding Proteins/metabolism
- Enzyme Activation
- Humans
- Intracellular Signaling Peptides and Proteins
- Isoenzymes/metabolism
- Mice
- Mitogen-Activated Protein Kinases/metabolism
- Molecular Sequence Data
- Myristic Acid
- PC12 Cells
- Phosphatidylinositol 3-Kinases/metabolism
- Phospholipase C gamma
- Phosphorylation
- Protein Tyrosine Phosphatase, Non-Receptor Type 1
- Protein Tyrosine Phosphatase, Non-Receptor Type 11
- Protein Tyrosine Phosphatase, Non-Receptor Type 6
- Protein Tyrosine Phosphatases/metabolism
- Protein-Tyrosine Kinases
- Rats
- Receptor Protein-Tyrosine Kinases/genetics
- Receptor Protein-Tyrosine Kinases/metabolism
- Receptor, Fibroblast Growth Factor, Type 1
- Receptor, Fibroblast Growth Factor, Type 3
- Receptor, Fibroblast Growth Factor, Type 4
- Receptors, Fibroblast Growth Factor/genetics
- Receptors, Fibroblast Growth Factor/metabolism
- STAT1 Transcription Factor
- STAT3 Transcription Factor
- Trans-Activators/metabolism
- Type C Phospholipases/metabolism
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Affiliation(s)
- K C Hart
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla 92093-0367, USA
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26
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Ulrich A, Schmitz AA, Braun T, Yuan T, Vogel HJ, Vergères G. Mapping the interface between calmodulin and MARCKS-related protein by fluorescence spectroscopy. Proc Natl Acad Sci U S A 2000; 97:5191-6. [PMID: 10792048 PMCID: PMC25804 DOI: 10.1073/pnas.090500397] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
MARCKS-related protein (MRP) is a myristoylated protein kinase C substrate that binds calmodulin (CaM) with nanomolar affinity. To obtain structural information on this protein, we have engineered 10 tryptophan residues between positions 89 and 104 in the effector domain, a 24-residue-long amphipathic segment that mediates binding of MRP to CaM. We show that the effector domain is in a polar environment in free MRP, suggesting exposure to water, in agreement with a rod-shaped structure of the protein. The effector domain participates in the binding of MRP to CaM, as judged by the dramatic changes observed in the fluorescent properties of the mutants on complex formation. Intermolecular quenching of the fluorescence emission of the tryptophan residues in MRP by selenomethionine residues engineered in CaM reveals that the N-terminal side of the effector domain contacts the C-terminal domain of CaM, whereas the C-terminal side of the effector domain contacts the N-terminal domain of CaM. Finally, a comparison of the fluorescent properties of the myristoylated and unmyristoylated forms of a construct in which a tryptophan residue was introduced at position 4 close to the myristoylated N terminus of MRP suggests that the lipid moiety is also involved in the interaction of MRP with CaM.
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Affiliation(s)
- A Ulrich
- Department of Biophysical Chemistry, Biozentrum, University of Basel, Klingelbergstrasse 70, CH-4056 Basel, Switzerland
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27
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Kragelund BB, Hauenschild A, Carlström G, Pongs O, Finn BE. 1H, 13C, and 15N assignments of un-myristoylated Ca2+-frequenin, a synaptic efficacy modulator. J Biomol NMR 2000; 16:85-86. [PMID: 10718617 DOI: 10.1023/a:1008383002568] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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28
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Abstract
The association of various protein constructs of MARCKS-related protein (MRP) lacking the myristoyl moiety or the basic effector domain (ED) or both to neutral and acidic supported planar phospholipid bilayer membranes has been monitored using two-mode optical waveguide spectroscopy. The importance of the myristoyl moiety for interaction with both neutral and acidic membranes is demonstrated but unmyristoylated MRP still binds appreciably to neutral membranes, albeit less than to acidic membranes. Only when both the myristoyl moiety and the ED are excised does the interaction fall to zero in the case of the acidic membranes, with very small residual binding still detectable in the presence of neutral membranes. These results point to the importance of hydrophobic interactions apart from those associated with the myristoyl moiety in the association of MRP with membranes. The ED is well endowed with hydrophobic as well as with basic residues, and the former are chiefly responsible for binding unmyristoylated MRP to neutral membranes: The very small residual attraction between MRP lacking both the myristoyl moiety and the ED is completely outweighed by electrostatic repulsion between the net acidic MRP and the acidic lipid head groups.
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Affiliation(s)
- J J Ramsden
- Biozentrum, University of Basel, Klingelbergstrasse 70, Basel, 4056, Switzerland
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29
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Hass MA, Nowak DM, Leonova E, Levin RM, Longhurst PA. Identification of components of Prunus africana extract that inhibit lipid peroxidation. Phytomedicine 1999; 6:379-388. [PMID: 11962548 DOI: 10.1016/s0944-7113(99)80063-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Extractive and chromatographic separations were performed on V-1326, a chloroform extract from the bark of Prunus africana (also referred to as Pygeum africanum), which is used to treat the symptoms associated with benign prostate hyperplasia (BPH). The relative amounts of eleven identified constituents in crude V-1326 and in separated fractions were determined using gas chromatographic analysis. The ability of V-1326 and its separated fractions to inhibit ferrous ion-induced stimulation of lipid peroxidation in microsomal preparations from rabbit livers was evaluated. The extract, V-1326, and fractions containing high levels of myristic acid potently inhibited lipid peroxidation.
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Affiliation(s)
- M A Hass
- Division of Basic and Pharmaceutical Sciences, Albany College of Pharmacy, NY 12208, USA.
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Sliwinski-Korell A, Engelhardt H, Kampka M, Lutz F. Oligomerization and structural changes of the pore-forming Pseudomonas aeruginosa cytotoxin. Eur J Biochem 1999; 265:221-30. [PMID: 10491177 DOI: 10.1046/j.1432-1327.1999.00718.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Pseudomonas aeruginosa produces a pathogenic factor, the 29-kDa pore-forming protein cytotoxin. Nonspecific oligomers of cytotoxin up to the hexamer, induced by oxidative crosslinking or detergent micellae, were based on intermolecular disulfide bridges. SDS induced tetramer, hexamer and mainly pentamers that were resistant to reducing conditions, indicating an additional oligomerization mechanism. Functional oligomerization after incubation with different membranes resulted in an oligomer of approximately 145 kDa that was identified as the pentamer by comparison with the SDS-induced oligomers. Covalent modification with diethylpyrocarbonate showed that histidine residues are indispensable for functional pentamerization. Pentamer formation was not influenced by the lipid composition of the liposomes tested, indicating that rising membrane fluidity did not increase oligomerization. The secondary structure of cytotoxin determined by spectroscopy is characterized by approximately 50% beta-sheet, 20% beta-turn, 10% alpha-helix and 20% remaining structure. Contact with detergent micellae or liposomes induced a reorganization of beta-structure associations, as observed by attenuated total reflection-Fourier transform infrared spectroscopy. Electron microscopy and principle component analysis of the cytotoxin monomer demonstrated a tapered molecule of 11 nm in length and a maximum width of 3.5 nm. These results classify the cytotoxin as a pore-forming toxin, rich in antiparallel beta-structure, that needs to oligomerize and inserts into membranes; it is very similar to the Staphylococcus aureus alpha-toxin.
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Affiliation(s)
- A Sliwinski-Korell
- Institut für Pharmakologie und Toxikologie, Justus-Liebig-Universität Giessen, Germany
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31
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Abstract
The effect of clobetasol 17-propionate (CP), a potent corticosteroid, in various cream bases on the permeation through artificial membrane was sought. Four formulations were then chosen for a further in vivo skin blanching assay. After calculation of the relationship between in vivo flux0-8 hr determined from a surface recovery technique and in vitro release rate0-8 hr of CP from various formulations, a high correlation coefficient of 0.9996 was achieved. Therefore, the in vitro release study could be used as an index to predict and evaluate the in vivo penetration capacity of CP cream to screen the effective formulation preclinically. After a series of in vivo investigations in this study, it was concluded that myristic acid-added formulations may show a bioequivalence with commercial Dermovate. Furthermore, the flux calculated from the surface recovery technique and delta E detected from the skin blanching assay may be useful as parameters evaluating the quality and effectiveness of CP cream.
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Affiliation(s)
- J Y Fang
- School of Pharmacy, Kaohsiung Medical College, Taiwan
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32
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Curtain CC, Lowe MG, Macreadie IG, Gentle IR, Lawrie GA, Azad AA. Structural requirements for the cytotoxicity of the N-terminal region of HIV type 1 Nef. AIDS Res Hum Retroviruses 1998; 14:1543-51. [PMID: 9840287 DOI: 10.1089/aid.1998.14.1543] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
We have found that the hemolytic and cytotoxic activities of myristoylated Nef N-terminal peptides require a net positive charge in the first seven amino residues of the sequence. The activities are considerably less dependent on the secondary structure of the peptides. Film balance studies showed that both active and inactive peptides interacted with neutral phospholipid monolayers, suggesting that binding to neutral lipids was not a sufficient condition for lytic activity. It was also found that nonmyristoylated N-terminal peptide did not interact to the same extent with the monolayer, indicating that myristoylation was essential for lipid interaction. It is considered that the positively charged residues of the proximate N terminus of Nef interact with acidic lipids of biological membranes, reinforcing the weak membrane-targeting properties of the myristyl chain. Parallels are drawn between this mode of interaction with membranes and that of members of the Src family of proteins, which are also myristoylated and have positively charged residues in their proximate N termini. In particular, these proteins and Nef also have serine residues in their proximal N-terminal regions, which when phosphorylated could neutralize the positive charge and thus provide a mechanism for modulating membrane interaction.
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Affiliation(s)
- C C Curtain
- Biomolecular Research Institute, Parkville, Victoria, Australia.
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33
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Kaneki H, Yokozawa J, Fujieda M, Mizuochi S, Ishikawa C, Ide H. Phorbol ester-induced production of prostaglandin E2 from phosphatidylcholine through the activation of phospholipase D in UMR-106 cells. Bone 1998; 23:213-22. [PMID: 9737343 DOI: 10.1016/s8756-3282(98)00100-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
To determine the effects of 12-O-tetradecanoylphorbol-13-acetate (TPA) on phospholipase D (PLD) activity in osteoblast-like UMR-106 cells, we used cells prelabeled with [3H] myristic acid or [3H] arachidonic acid, which were preferentially incorporated to phosphatidylcholine. The treatment of [3H] myristate-labeled cells with TPA in the presence of 1% ethanol caused a dose-dependent formation of [3H] phosphatidylethanol (PEt), a product specific to PLD, suggesting an activation of this enzyme. Pretreatment of the cells with protein kinase C (PKC) inhibitors (GF109203X, staurosporine or H-7) abolished the TPA-dependent formation of PEt. The PEt formation in response to TPA treatment was not observed after the pretreatment of the cells with TPA to downregulate PKC. These results suggest the involvement of PKC in the TPA-induced activation of PLD. With [3H] arachidonate-labeled cells, TPA treatment in the absence of ethanol resulted in the liberation of [3H] arachidonic acid, which was gradually converted to prostaglandin E2 (PGE2), but the accumulations of [3H] phosphatidic acid (PA) and [3H] diacylglycerol (DAG) were very small and temporary. In contrast, PA was linearly accumulated following TPA treatment, when the cells were pretreated with an inhibitor of phosphatidate phosphohydrolase (PAP), propranolol, with no accumulation of either DAG or arachidonic acid. The TPA treatment of the cells pretreated with a DAG lipase inhibitor, RHC-80267, caused the generation of DAG after a lag period of approximately 5 min, with a very small and temporary accumulation of PA. The TPA treatment of cells pretreated with a cyclooxygenase (COX) inhibitor, indomethacin, blocked the PGE2 production. The TPA-induced PGE2 production was not affected by the pretreatment of cells with a phospholipase A2 inhibitor, p-bromophenacylbromide, or with a phospholipase C inhibitor, D-609. TPA also stimulated PGE2 production in osteoblastic cells that were enzymatically isolated from adult rat calvaria, and the experiments with lipid metabolizing enzyme inhibitors gave the same profile of inhibition of TPA-induced PGE2 production as was observed in UMR-106 cells. These results suggest that PA formed as a consequence of the activation of PLD by TPA is rapidly converted to arachidonic acid via a PAP/DAG lipase pathway, followed by a gradual conversion of arachidonic acid to PGE2 by COX in both UMR-106 cells and isolated adult osteoblastic cells, and that neither phospholipase A2 nor phospholipase C is involved in the TPA-induced PGE2 production. To the best of our knowledge, this is the first report that shows that the activation of PKC in osteoblastic cells leads to the production of PGE2 via a PLD/PAP/DAG lipase/COX pathway.
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Affiliation(s)
- H Kaneki
- Department of Hygienic Chemistry, School of Pharmaceutical Sciences, Toho University, Chiba, Japan
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Gazina EV, Lin B, Gallina A, Milanesi G, Anderson DA. Intracellular retention of duck hepatitis B virus large surface protein is independent of preS topology. Virology 1998; 242:266-78. [PMID: 9514970 DOI: 10.1006/viro.1997.9015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The mechanism of intracellular retention for the large surface protein (L) of duck hepatitis B virus (DHBV) was analyzed by examination of the transmembrane topologies and secretory properties of a collection of DHBV L mutants and compared with that of human hepatitis B virus (HBV) L. Our results demonstrate that, in contrast to its HBV counterpart, intracellular retention of DHBV L does not depend on the cytosolic disposition of its preS domain. L mutants with either cytosolic or lumenal preS were mostly retained in the absence of the small surface protein (S), whereas coexpression with S resulted in efficient secretion of both topological forms. Coexpression of the wild-type DHBV L with S resulted in efficient incorporation of L into secreted S + L particles, whereas HBV L was partially excluded from secreted particles under the same conditions. We propose that HBV provides L retention even in the presence of an excess of S, by exclusion of molecules with cytosolic preS domains from secreted particles at the stage of their assembly. DHBV lacks such a retention mechanism due to the absence of topological selection in particulate assembly.
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Affiliation(s)
- E V Gazina
- Macfarlane Burnet Centre for Medical Research, Fairfield, Victoria, Australia
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35
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Schwarz D, Kisselev P, Pfeil W, Pisch S, Bornscheuer U, Schmid RD. Evidence that nonbilayer phase propensity of the membrane is important for the side chain cleavage activity of cytochrome P450SCC. Biochemistry 1997; 36:14262-70. [PMID: 9369499 DOI: 10.1021/bi9714262] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
To analyze whether specific protein-lipid interactions or physical features of the membrane contribute to cytochrome P450SCC (CYP11A1) activation by lipids, dimyristoylphosphatidylcholine/cardiolipin and dimyristoylphosphatidylcholine/branched phosphatidylcholine vesicles of defined acyl chain structure were studied for their ability to stimulate the side chain cleavage activity of the enzyme. Activation was found to increase with the mole percent of nonbilayer lipids in the system and the chain lengths of both the branched and main fatty acyl chains of the activator lipid. Unsaturation provided by dioleoylphosphatidylcholine as host lipid leads to a further increase in the potency of the branched phosphatidylcholines to activate the enzyme. The observed activation can be qualitatively interpreted in terms of the effect of these lipids on the hydrophobic volume of the membrane. Using differential scanning calorimetry, we showed that the branched phosphatidylcholines perturb the bilayer membrane structure of dimyristoylphosphatidylcholine and lower the bilayer to hexagonal phase transition temperature of dielaidoylphosphatidylethanolamine, i.e., promote hexagonal phase formation. We also examined the effect of eicosane on both the cytochrome P450SCC activity and the lipid polymorphism and found that eicosane increases both the activity and the hexagonal phase propensity of the vesicle membrane. Because of these correlations, we conclude that the nonbilayer phase propensity of the membrane rather than specific binding of activator lipids to the enzyme explains best the observed activation of enzymatic activity by the lipids.
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Affiliation(s)
- D Schwarz
- Max Delbrueck Center of Molecular Medicine, D-13125 Berlin-Buch, Germany.
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36
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Lange A, Gebremedhin D, Narayanan J, Harder D. 20-Hydroxyeicosatetraenoic acid-induced vasoconstriction and inhibition of potassium current in cerebral vascular smooth muscle is dependent on activation of protein kinase C. J Biol Chem 1997; 272:27345-52. [PMID: 9341185 DOI: 10.1074/jbc.272.43.27345] [Citation(s) in RCA: 143] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
20-Hydroxyeicosatetraenoic acid (20-HETE), a cytochrome P450 metabolite of arachidonic acid, is a potent vasoconstrictor, and has been implicated in the myogenic activation of renal and cerebral arteries. We examined the role of protein kinase C (PKC) in the signal transduction pathway by which 20-HETE induces vasoconstriction and inhibition of whole-cell K+ current in cat cerebral vascular smooth muscle. 20-HETE induced a concentration-dependent constriction in isolated pressurized cat middle cerebral arteries (-29 +/- 8% at 1 microM). However, in the presence of an N-myristoylated PKC pseudosubstrate inhibitor peptide (MyrPsiPKC-I(19-27)), 20-HETE induced a concentration-dependent vasodilation (26 +/- 4% at 1 microM). In whole-cell voltage clamp studies, application of 20-HETE inhibited whole-cell K+ current recorded in cat cerebral vascular smooth muscle cells, an effect that was attenuated by MyrPsiPKC-I(19-27). Further evidence for the role of PKC activation in response to 20-HETE is the finding that 20-HETE increased the phosphorylation of myristoylated, alanine-rich PKC substrate in cultured cat cerebral vascular smooth muscle cells in a concentration- and PKC-dependent manner. These data provide evidence that PKC is an integral part of the signal transduction pathway by which 20-HETE elicits vasoconstriction of cerebral arteries and inhibition of whole-cell K+ current in cat cerebral vascular smooth muscle.
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Affiliation(s)
- A Lange
- Cardiovascular Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA
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37
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Webster MK, Donoghue DJ. Enhanced signaling and morphological transformation by a membrane-localized derivative of the fibroblast growth factor receptor 3 kinase domain. Mol Cell Biol 1997; 17:5739-47. [PMID: 9315632 PMCID: PMC232422 DOI: 10.1128/mcb.17.10.5739] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Fibroblast growth factor (FGF) receptors (FGFRs) are membrane-spanning tyrosine kinase receptors that mediate regulatory signals for cell proliferation and differentiation in response to FGFs. We have previously determined that the Lys650-->Glu mutation in the activation loop of the kinase domain of FGFR3, which is responsible for the lethal skeletal dysplasia thanatophoric dyplasia type II (TDII), greatly enhances the ligand-independent kinase activity of the receptor. Here, we demonstrate that expression of this construct induces a c-fos promoter construct approximately 10-fold but does not lead to proliferation or morphological transformation of NIH 3T3 cells. In contrast, the isolated kinase domain of activated FGFR3, targeted to the plasma membrane by a myristylation signal, is able to stimulate c-fos expression by 40-fold, induce proliferation of quiescent cells, and morphologically transform fibroblasts. This result suggests that the extracellular and transmembrane domains of FGFRs exert a negative regulatory influence on the activity of the kinase domain. Targeting of the activated kinase domain to either the cytoplasm or the nucleus does not significantly affect biological signaling, suggesting that signals from FGFR3 resulting in mitogenesis originate exclusively from the plasma membrane. Furthermore, our novel observation that expression of a highly activated FGFR3 kinase domain is able to morphologically transform fibroblasts suggests that dysregulation of FGFR3 has the potential to play a role in human neoplasia.
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Affiliation(s)
- M K Webster
- Department of Chemistry and Biochemistry and Center for Molecular Genetics, University of California, San Diego, La Jolla 92093-0367, USA
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38
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Mitchelhill KI, Michell BJ, House CM, Stapleton D, Dyck J, Gamble J, Ullrich C, Witters LA, Kemp BE. Posttranslational modifications of the 5'-AMP-activated protein kinase beta1 subunit. J Biol Chem 1997; 272:24475-9. [PMID: 9305909 DOI: 10.1074/jbc.272.39.24475] [Citation(s) in RCA: 119] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The AMP-activated protein kinase (AMPK) consists of catalytic alpha and noncatalytic beta and gamma subunits and is responsible for acting as a metabolic sensor for AMP levels. There are multiple genes for each subunit and the rat liver AMPK alpha1 and alpha2 catalytic subunits are associated with beta1 and gamma1 noncatalytic subunits. We find that the isolated gamma1 subunit is N-terminally acetylated with no other posttranslational modification. The isolated beta1 subunit is N-terminally myristoylated. Transfection of COS cells with AMPK subunit cDNAs containing a nonmyristoylatable beta1 reduces, but does not eliminate, membrane binding of AMPK heterotrimer. The isolated beta1 subunit is partially phosphorylated at three sites, Ser24/25, Ser182, and Ser108. The Ser24/25 and Ser108 sites are substoichiometrically phosphorylated and can be autophosphorylated in vitro. The Ser-Pro site in the sequence LSSS182PPGP is stoichiometrically phosphorylated, and no additional phosphate is incorporated into this site with autophosphorylation. Based on labeling studies in transfected cells, we conclude that alpha1 Thr172 is a major, although not exclusive, site of both basal and stimulated alpha1 phosphorylation by an upstream AMPK kinase.
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Affiliation(s)
- K I Mitchelhill
- St. Vincent's Institute of Medical Research, 41 Victoria Parade, Fitzroy, Victoria 3065 Australia
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39
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Abstract
A mutation at the surface of the substrate access channel which dramatically decreases the affinity for some fatty acids in P450(BM-3) was discovered by random mutagenesis. The mutation introduced, proline-25 to glutamine, is in close proximity to the arginine-47 residue thought to be responsible for the initial docking of fatty acid substrates. The P25Q mutant displays an affinity for palmitate which is approximately 100-fold weaker than the wild-type enzyme. In addition to its altered substrate affinity, P25Q also exhibits altered hydroxylation specificity and carbon monoxide recombination kinetics in the substrate-free form.
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Affiliation(s)
- S A Maves
- Beckman Institute for Advanced Science and Technology and Department of Biochemistry, University of Illinois, Urbana 61801, USA
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40
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Sunshine MG, Gibson BW, Engstrom JJ, Nichols WA, Jones BD, Apicella MA. Mutation of the htrB gene in a virulent Salmonella typhimurium strain by intergeneric transduction: strain construction and phenotypic characterization. J Bacteriol 1997; 179:5521-33. [PMID: 9287009 PMCID: PMC179425 DOI: 10.1128/jb.179.17.5521-5533.1997] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The htrB gene product of Haemophilus influenzae contributes to the toxicity of the lipooligosaccharide. The htrB gene encodes a 2-keto-3-deoxyoctulosonic acid-dependent acyltransferase which is responsible for myristic acid substitutions at the hydroxy moiety of lipid A beta-hydroxymyristic acid. Mass spectroscopic analysis has demonstrated that lipid A from an H. influenzae htrB mutant is predominantly tetraacyl and similar in structure to lipid IV(A), which has been shown to be nontoxic in animal models. We sought to construct a Salmonella typhimurium htrB mutant in order to investigate the contribution of htrB to virulence in a well-defined murine typhoid model of animal pathogenesis. To this end, an r- m+ galE mutS recD strain of S. typhimurium was constructed (MGS-7) and used in inter- and intrastrain transduction experiments with both coliphage P1 and Salmonella phage P22. The Escherichia coli htrB gene containing a mini-Tn10 insertion was transduced from E. coli MLK217 into S. typhimurium MGS-7 via phage P1 and subsequently via phage P22 into the virulent Salmonella strain SL1344. All S. typhimurium transductants showed phenotypes similar to those described for the E. coli htrB mutant. Mass spectrometric analysis of the crude lipid A fraction from the lipopolysaccharide of the S. typhimurium htrB mutant strain showed that for the dominant hexaacyl form, a lauric acid moiety was lost at one position on the lipid A and a palmitic acid moiety was added at another position; for the less abundant heptaacyl species, the lauric acid was replaced with palmitoleic acid.
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Affiliation(s)
- M G Sunshine
- Department of Microbiology, The University of Iowa, Iowa City 52242, USA
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41
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Bütikofer P, Ruepp S, Boschung M, Roditi I. 'GPEET' procyclin is the major surface protein of procyclic culture forms of Trypanosoma brucei brucei strain 427. Biochem J 1997; 326 ( Pt 2):415-23. [PMID: 9291113 PMCID: PMC1218686 DOI: 10.1042/bj3260415] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The surface of Trypanosoma brucei brucei insect forms is covered by an invariant protein coat consisting of procyclins. There are six or seven procyclin genes that encode unusual proteins with extensive tandem repeat units of glutamic acid (E) and proline (P) (referred to as EP repeats), and two genes that encode proteins with internal pentapeptide (GPEET) repeats. Although the EP forms of procyclins have been isolated and characterized by several laboratories, evidence for GPEET procyclin has largely been confined to the expression of its mRNA. To characterize GPEET procyclin further, we isolated the protein from T. b. brucei strain 427. We found that label from [3H]myristic acid and [3H]ethanolamine was incorporated into GPEET procyclin and we demonstrated the protein's covalent modification with a glycosylphosphatidylinositol anchor. The major form of GPEET procyclin showed an apparent molecular mass of 22-32 kDa, was susceptible to proteolytic treatment and was found to be phosphorylated. Surprisingly, our results show that GPEET procyclin represents the major form of procyclin in T. b. brucei 427 culture forms and that the ratio of EP to GPEET procyclin can vary considerably between different cell lines.
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Affiliation(s)
- P Bütikofer
- Institut für Biochemie und Molekularbiologie, Universität Bern, Switzerland
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42
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Spearman P, Horton R, Ratner L, Kuli-Zade I. Membrane binding of human immunodeficiency virus type 1 matrix protein in vivo supports a conformational myristyl switch mechanism. J Virol 1997; 71:6582-92. [PMID: 9261380 PMCID: PMC191936 DOI: 10.1128/jvi.71.9.6582-6592.1997] [Citation(s) in RCA: 176] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The interaction of the human immunodeficiency virus (HIV) Gag protein with the plasma membrane of a cell is a critical event in the assembly of HIV particles. The matrix protein region (MA) of HIV type 1 (HIV-1) Pr55Gag has previously been demonstrated to confer membrane-binding properties on the precursor polyprotein. Both the myristic acid moiety and additional determinants within MA are essential for plasma membrane binding and subsequent particle formation. In this study, we demonstrated the myristylation-dependent membrane interaction of MA in an in vivo membrane-binding assay. When expressed within mammalian cells, MA was found both in association with cellular membranes and in a membrane-free form. In contrast, the intact precursor Pr55Gag molecule analyzed in an identical manner was found almost exclusively bound to membranes. Both membrane-bound and membrane-free forms of MA were myristylated and phosphorylated. Differential membrane binding was not due to the formation of multimers, as dimeric and trimeric forms of MA were also found in both membrane-bound and membrane-free fractions. To define the requirements for membrane binding of MA, we analyzed the membrane binding of a series of MA deletion mutants. Surprisingly, deletions within alpha-helical regions forming the globular head of MA led to a dramatic increase in overall membrane binding. The stability of the MA-membrane interaction was not affected by these deletions, and no deletion eliminated membrane binding of the molecule. These results establish that myristic acid is a primary determinant of the stability of the Gag protein-membrane interaction and provide support for the hypothesis that a significant proportion of HIV-1 MA molecules may adopt a conformation in which myristic acid is hidden and unavailable for membrane interaction.
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Affiliation(s)
- P Spearman
- Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-2581, USA.
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43
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Furuishi K, Matsuoka H, Takama M, Takahashi I, Misumi S, Shoji S. Blockage of N-myristoylation of HIV-1 gag induces the production of impotent progeny virus. Biochem Biophys Res Commun 1997; 237:504-11. [PMID: 9299393 DOI: 10.1006/bbrc.1997.7178] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The role of the N-myristoylation of the human immunodeficiency virus type 1 (HIV-1) gag protein in ACH-2 cells was studied. The infectivity of HIV-1 from the cells stimulated with phorbol 12-myristate 13-acetate (PMA) was suppressed by pretreatment with N-myristoyl glycinal diethylacetal (N-Myr-GOA), a potent N-myristoylation inhibitor, and the blockage of myristoylation resulted in accumulation of immature gag precursors. The viral particles which budded from the non-N-Myr-GOA-treated ACH-2 cells stimulated with PMA exhibited a typical viral phenotype, whereas those which budded from the N-Myr-GOA-treated ACH-2 cells stimulated with PMA were twisted, as observed electron microscopically. In electron microscopic analyses with gold-labeled monoclonal antibodies to gag and env, gag and env were detected adjacent to each other in the PMA-stimulated ACH-2, but no env was detected in the cells treated with N-Myr-GOA. Taken together, the results suggest that the myristoylation of HIV-1 gag seems to be responsible for both maturation of gag and acquisition of HIV-1 infectivity.
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Affiliation(s)
- K Furuishi
- Department of Biochemistry, Faculty of Pharmaceutical Sciences, Kumamoto University, Japan
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44
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Abstract
Cell membrane association by several important peripheral proteins, such as Src, MARCKS, HIV-1 Gag, and K-Ras, requires nonspecific electrostatic interactions between a cluster of basic residues on the protein and acidic phospholipids in the plasma membrane. A simple theoretical model based on the nonlinear Poisson-Boltzmann equation describes well the experimentally measured electrostatic association between such proteins and the cell membrane.
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Affiliation(s)
- D Murray
- Department of Physiology and Biophysics, SUNY Stony Brook 11794-8661, USA
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45
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Fackler OT, Kienzle N, Kremmer E, Boese A, Schramm B, Klimkait T, Kücherer C, Mueller-Lantzsch N. Association of human immunodeficiency virus Nef protein with actin is myristoylation dependent and influences its subcellular localization. Eur J Biochem 1997; 247:843-51. [PMID: 9288906 DOI: 10.1111/j.1432-1033.1997.00843.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Human immunodeficiency virus (HIV) Nef functions are thought to be mediated via interactions with cellular proteins. Utilizing zone velocity sedimentation in glycerol gradients we found that recombinant HIV-1 Nef non-covalently associates with actin forming a high-molecular-mass complex of 150-300 kDa. This Nef/actin complex was present in human B and T lymphocytes but not in insect cells and was dependent on the N-terminal myristoylation of Nef, whereas the SH3-binding proline motif of Nef was not involved. Despite being myristoylated, HIV-2 Nef did not associate with actin. This might reflect differences in the subcellular localization of Nef since cell-fractionation experiments revealed that HIV-1 Nef was virtually exclusively localized in the cytoskeletal (detergent-insoluble) fraction whereas HIV-2 Nef had significantly reduced affinity for the cytoskeleton. Colocalization experiments in HIV-1-infected CD4+ fibroblasts revealed that Nef/actin complexes may also exist in HIV-infected cells. This novel interaction of HIV-1 Nef with actin provides insight into the association of Nef with cellular structures and reveals general differences in the interactions of the Nef proteins from HIV-1 and HIV-2.
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Affiliation(s)
- O T Fackler
- Universitätskliniken des Saarlandes, Institut für Med. Mikrobiologie und Hygiene, Abt. Virologie, Homburg/Saar, Germany
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46
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Abstract
QM is a human cDNA originally isolated as a transcript elevated in a nontumorigenic Wilms' tumor microcell hybrid, relative to the tumorigenic parental cell line. Homologs of this gene have been identified from a large number of diverse eukaryotic species which demonstrate a high degree of conservation. The functional importance implied by this strong conservation is supported by the observation that the disruption of the yeast homolog is lethal. In spite of its apparent importance, the function of the encoded protein remains elusive. Indirect immunofluorescent cell staining of cultured human, G401 cells with an antibody to the QM protein shows a punctate staining pattern in the cytoplasm with much of the signal in a perinuclear pattern. Subcellular fractionation demonstrated an association of QM protein with the rough endoplasmic reticulum. It was possible to disrupt this association by washing microsomal membranes with 1M NaCl, suggesting a peripheral association. Proteolytic latency studies showed the protein to be exposed on the cytoplasmic face of the membrane. In situ cross-linking followed by diagonal SDS gel analysis indicates that QM exists as a member of a large protein complex. In agreement with this, QM was found to copurify with the ribosome complex. Incubation with 1 M NaCl was found to disrupt this association while having no effect on the association of core ribosomal proteins.
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Affiliation(s)
- T M Loftus
- Department of Microbiology and Molecular Genetics, College of Medicine, University of California, Irvine, California 92697, USA
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47
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Tnani M, Aliau S, Bayard B. Upregulation of a myristylated 74-kDa protein by interferon treatment of Daudi cells. J Interferon Cytokine Res 1997; 17:425-9. [PMID: 9243376 DOI: 10.1089/jir.1997.17.425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Labeling of unstimulated human Daudi B lymphoblastoid cells with exogenously added [3H]myristate resulted in acylation of a broad spectrum of different proteins, most of which are currently unknown. Among this array of labeled proteins, a unique 74-kDa acylated protein was induced in interferon (IFN)-treated cells. In the present study, we defined the myristylation kinetics of this protein and examined the subcellular distribution before and after activation with IFN-alpha/beta. This acylated protein was detected only at a very low level in the membrane fraction of untreated cells, and its level increased 3-4-fold by treatment with IFN. This induction occurred over a short period of time and was IFN-alpha/beta dose-dependent. No significant induction was observed with IFN-gamma. Incorporation of [3H]myristate was completely abolished by cycloheximide. The fatty acid associated with this protein was probably linked to a nascent chain through an amide linkage, as it was not released by alkaline hydroxylamine treatment and was identified as myristic acid by HPLC after its release from the polypeptide chain by acid methanolysis. In contrast to other IFN-induced proteins, whose synthesis started at 10 h and was maintained for 20 h, this protein was present in the plasma membrane for a short period of time, between 4 and 6 h after IFN-alpha/beta treatment, and was no longer present in this cellular compartment. This event appears to be transient and suggests that a degradation or a negative regulation of transcription starts from 6-7 h after continuous IFN treatment. As many other myristylated proteins are implicated in cellular regulation, it is possible that this 74-kDa protein may have a regulatory role in cell proliferation and the inhibition of viral replication.
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Affiliation(s)
- M Tnani
- CNRS, UMR 5539, Université Montpellier II-Sciences et Techniques du Languedoc, France
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48
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Williams JP, Blair HC, McDonald JM, McKenna MA, Jordan SE, Williford J, Hardy RW. Regulation of osteoclastic bone resorption by glucose. Biochem Biophys Res Commun 1997; 235:646-51. [PMID: 9207213 DOI: 10.1006/bbrc.1997.6795] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Osteoclasts degrade bone by pumping molar quantities of HCl to dissolve the calcium salts of bone, an energy intensive process evidently supported by abundant mitochondria. This is the first study to directly examine the ability of various metabolites to serve as potential energy sources for osteoclastic bone resorption. Glucose, and to a lesser extent lactate, supported osteoclastic bone degradation. However, fatty acids (palmitate, myristate and stearate), essential amino acids plus 20 mM alanine, or ketone bodies (acetoacetate, beta-hydroxybutyrate and alpha-ketoglutarate) did not support bone degradation. Resorption declined to 10-30% of glucose controls when fatty acids or ketoacids were substituted for glucose. Resorption was glucose concentration dependent, with maximal activity at approximately 7 mM (K(M) approximately 3 mM). Glucose transport was linear for approximately 15 minutes, specific for D-glucose, and inhibited by cytochalasin B. Osteoclasts cultured on bone transported glucose at almost twice the rate of those off bone (Vmax 23 versus 13 nmols/mg/min, respectively) and medium acid accumulation paralleled glucose uptake, while the K(M) was unchanged. We conclude that glucose is the principal energy source required for bone degradation. Further, characteristics of glucose transport are consistent with the hypothesis that fluctuations in serum glucose concentration are an important component in regulation of osteoclastic bone degradation.
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Affiliation(s)
- J P Williams
- Department of Pathology, The University of Alabama at Birmingham 35294, USA
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49
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Abstract
We have previously shown that alpha2-adrenergic receptor-mediated coupling to phospholipase D (PLD) in vascular tissues requires a tyrosine kinase activity (Jinsi, A., Paradise, J., and Deth, R. C. (1996) Eur. J. Pharmacol. 302, 183-190). To further clarify this mode of regulation we reconstituted alpha2A/D-adrenergic receptor-stimulated PLD activity in PC12 cells expressing the cloned receptor. [3H]Myristic acid-labeled cells were lysed by nitrogen cavitation, and aliquots of subnuclear fraction were utilized in the PLD assay. Agonist-stimulated PLD activity was measured in the presence of 0.4% butanol as [3H]phosphatidylbutanol formation. Both GTP and its non-hydrolyzable analog guanosine 5'-O-(thiotriphosphate) stimulated PLD activity in a concentration- and time-dependent manner that required co-activation of protein kinase C by phorbol dibutyrate. Addition of epinephrine produced a 3-fold stimulation of PLD activity in the presence of GTP and GDP. This agonist-stimulated PLD activity was completely blocked by the alpha2-adrenergic receptor antagonist rauwolscine and by Clostridium botulinum toxin as well as by antibodies directed against either pp60(src), RhoA, or Ras GTPase-activating protein. These results indicate that coupling of the alpha2A/D-adrenergic receptor to PLD is complexly regulated by both the tyrosine kinase pp60(src) and the low molecular weight G protein RhoA.
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Affiliation(s)
- A Jinsi-Parimoo
- Department of Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts 02115, USA
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50
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Abstract
Stable human cell lines expressing the human immunodeficiency virus type I (HIV-I) Nef protein from inducible promoters were used to analyze the phosphorylation status of Nef in vivo. Nef phosphorylation in both HeLa and Jurkat cells was stimulated by phorbol ester treatment. Phosphoamino acid analysis revealed a predominance of phosphoserine with a small proportion of phosphothreonine. Treatment of cells with selective protein kinase inhibitors revealed that Nef phosphorylation was markedly reduced by bisindolylmaleimide, an inhibitor of protein kinase C, but was unaffected by inhibitors of mitogen-activated protein kinase kinase or cAMP-dependent kinase. These data implicate protein kinase C in Nef phosphorylation in vivo, and thus confirm and extend earlier in vitro data. Phosphorylation of a nonmyristoylated Nef mutant was impaired, suggesting that membrane targeting of Nef was required for phosphorylation. This was expected given that activated protein kinase C translocates from the cytosol to the plasma membrane. However, analysis of the subcellular localization of phosphorylated wild-type Nef revealed that both the cytosolic and membrane-associated pools of Nef were phosphorylated to an equivalent extent. Thus the significance of myristoylation for Nef function may be in influencing protein conformation, although these data could be explained by a transient and dynamic interaction between myristoylated Nef and the plasma membrane.
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Affiliation(s)
- K Coates
- MRC Retrovirus Research Laboratory, Department of Veterinary Pathology, University of Glasgow, Glasgow G61 1QH, Scotland, United Kingdom
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