1
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Huang X, Zhou Y, Sun Y, Wang Q. Intestinal fatty acid binding protein: A rising therapeutic target in lipid metabolism. Prog Lipid Res 2022; 87:101178. [PMID: 35780915 DOI: 10.1016/j.plipres.2022.101178] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Accepted: 06/27/2022] [Indexed: 10/17/2022]
Abstract
Fatty acid binding proteins (FABPs) are key proteins in lipid transport, and the isoforms are segregated according to their tissue origins. Several isoforms, such as adipose-FABP and epidermal-FABP, have been shown to participate in multiple pathologic processes due to their ubiquitous expression. Intestinal fatty acid binding protein, also termed FABP2 or I-FABP, is specifically expressed in the small intestine. FABP2 can traffic lipids from the intestinal lumen to enterocytes and bind superfluous fatty acids to maintain a steady pool of fatty acids in the epithelium. As a lipid chaperone, FABP2 can also carry lipophilic drugs to facilitate targeted transport. When the integrity of the intestinal epithelium is disrupted, FABP2 is released into the circulation. Thus, it can potentially serve as a clinical biomarker. In this review, we discuss the pivotal role of FABP2 in intestinal lipid metabolism. We also summarize the molecular interactions that have been reported to date, highlighting the clinical prospects of FABP2 research.
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Affiliation(s)
- Xi Huang
- Shanghai Institute of Immunology, Department of Gastroenterology of Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Youci Zhou
- Shanghai Institute of Immunology, Department of Gastroenterology of Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Yunwei Sun
- Shanghai Institute of Immunology, Department of Gastroenterology of Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Qijun Wang
- Shanghai Institute of Immunology, Department of Gastroenterology of Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China.
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2
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Toke O. Structural and Dynamic Determinants of Molecular Recognition in Bile Acid-Binding Proteins. Int J Mol Sci 2022; 23:ijms23010505. [PMID: 35008930 PMCID: PMC8745080 DOI: 10.3390/ijms23010505] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 12/30/2021] [Accepted: 12/31/2021] [Indexed: 12/12/2022] Open
Abstract
Disorders in bile acid transport and metabolism have been related to a number of metabolic disease states, atherosclerosis, type-II diabetes, and cancer. Bile acid-binding proteins (BABPs), a subfamily of intracellular lipid-binding proteins (iLBPs), have a key role in the cellular trafficking and metabolic targeting of bile salts. Within the family of iLBPs, BABPs exhibit unique binding properties including positive binding cooperativity and site-selectivity, which in different tissues and organisms appears to be tailored to the local bile salt pool. Structural and biophysical studies of the past two decades have shed light on the mechanism of bile salt binding at the atomic level, providing us with a mechanistic picture of ligand entry and release, and the communication between the binding sites. In this review, we discuss the emerging view of bile salt recognition in intestinal- and liver-BABPs, with examples from both mammalian and non-mammalian species. The structural and dynamic determinants of the BABP-bile–salt interaction reviewed herein set the basis for the design and development of drug candidates targeting the transcellular traffic of bile salts in enterocytes and hepatocytes.
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Affiliation(s)
- Orsolya Toke
- Laboratory for NMR Spectroscopy, Structural Research Centre, Research Centre for Natural Sciences, 2 Magyar Tudósok Körútja, H-1117 Budapest, Hungary
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3
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Structure and ligand binding of As-p18, an extracellular fatty acid binding protein from the eggs of a parasitic nematode. Biosci Rep 2019; 39:BSR20191292. [PMID: 31273060 PMCID: PMC6646235 DOI: 10.1042/bsr20191292] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 06/26/2019] [Accepted: 07/02/2019] [Indexed: 02/02/2023] Open
Abstract
Intracellular lipid-binding proteins (iLBPs) of the fatty acid-binding protein (FABP) family of animals transport, mainly fatty acids or retinoids, are confined to the cytosol and have highly similar 3D structures. In contrast, nematodes possess fatty acid-binding proteins (nemFABPs) that are secreted into the perivitelline fluid surrounding their developing embryos. We report structures of As-p18, a nemFABP of the large intestinal roundworm Ascaris suum, with ligand bound, determined using X-ray crystallography and nuclear magnetic resonance spectroscopy. In common with other FABPs, As-p18 comprises a ten β-strand barrel capped by two short α-helices, with the carboxylate head group of oleate tethered in the interior of the protein. However, As-p18 exhibits two distinctive longer loops amongst β-strands not previously seen in a FABP. One of these is adjacent to the presumed ligand entry portal, so it may help to target the protein for efficient loading or unloading of ligand. The second, larger loop is at the opposite end of the molecule and has no equivalent in any iLBP structure yet determined. As-p18 preferentially binds a single 18-carbon fatty acid ligand in its central cavity but in an orientation that differs from iLBPs. The unusual structural features of nemFABPs may relate to resourcing of developing embryos of nematodes.
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4
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Zamarreño F, Giorgetti A, Amundarain MJ, Viso JF, Córsico B, Costabel MD. Conserved charged amino acids are key determinants for fatty acid binding proteins (FABPs)-membrane interactions. A multi-methodological computational approach. J Biomol Struct Dyn 2017; 36:861-877. [PMID: 28298157 DOI: 10.1080/07391102.2017.1301271] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Based on the analysis of the mechanism of ligand transfer to membranes employing in vitro methods, Fatty Acid Binding Protein (FABP) family has been divided in two subgroups: collisional and diffusional FABPs. Although the collisional mechanism has been well characterized employing in vitro methods, the structural features responsible for the difference between collisional and diffusional mechanisms remain uncertain. In this work, we have identified the amino acids putatively responsible for the interaction with membranes of both, collisional and diffusional, subgroups of FABPs. Moreover, we show how specific changes in FABPs' structure could change the mechanism of interaction with membranes. We have computed protein-membrane interaction energies for members of each subgroup of the family, and performed Molecular Dynamics simulations that have shown different configurations for the initial interaction between FABPs and membranes. In order to generalize our hypothesis, we extended the electrostatic and bioinformatics analysis over FABPs of different mammalian genus. Also, our methodological approach could be used for other systems involving protein-membrane interactions.
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Affiliation(s)
- Fernando Zamarreño
- a Departamento de Física, Grupo de Biofísica - UNS , IFISUR, Universidad Nacional del Sur, CONICET , Bahía Blanca , Argentina
| | - Alejandro Giorgetti
- b Department of Biotechnology, Faculty of Mathematical , Physical and Natural Sciences, University of Verona , Verona , Italy
| | - María Julia Amundarain
- a Departamento de Física, Grupo de Biofísica - UNS , IFISUR, Universidad Nacional del Sur, CONICET , Bahía Blanca , Argentina
| | - Juan Francisco Viso
- a Departamento de Física, Grupo de Biofísica - UNS , IFISUR, Universidad Nacional del Sur, CONICET , Bahía Blanca , Argentina
| | - Betina Córsico
- c Facultad de Ciencias Médicas, Instituto de Investigaciones Bioquímicas de La Plata (CONICET-UNLP) , Universidad Nacional de La Plata , La Plata , Argentina
| | - Marcelo D Costabel
- a Departamento de Física, Grupo de Biofísica - UNS , IFISUR, Universidad Nacional del Sur, CONICET , Bahía Blanca , Argentina
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5
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Pan Y, Scanlon MJ, Owada Y, Yamamoto Y, Porter CJH, Nicolazzo JA. Fatty Acid-Binding Protein 5 Facilitates the Blood–Brain Barrier Transport of Docosahexaenoic Acid. Mol Pharm 2015; 12:4375-85. [DOI: 10.1021/acs.molpharmaceut.5b00580] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | | | - Yuji Owada
- Department
of Organ Anatomy, Yamaguchi University Graduate School of Medicine, Minami-kogushi
1-1-1, Ube 755-8505, Japan
- Department
of Organ Anatomy, Tohoku University Graduate School of Medicine, Seiryo-machi
2-1, Aoba-ku, Sendai 980-8575, Japan
| | - Yui Yamamoto
- Department
of Organ Anatomy, Yamaguchi University Graduate School of Medicine, Minami-kogushi
1-1-1, Ube 755-8505, Japan
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6
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Gajda AM, Storch J. Enterocyte fatty acid-binding proteins (FABPs): different functions of liver and intestinal FABPs in the intestine. Prostaglandins Leukot Essent Fatty Acids 2015; 93:9-16. [PMID: 25458898 PMCID: PMC4323920 DOI: 10.1016/j.plefa.2014.10.001] [Citation(s) in RCA: 108] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Accepted: 10/03/2014] [Indexed: 02/07/2023]
Abstract
Fatty acid-binding proteins (FABP) are highly abundant cytosolic proteins that are expressed in most mammalian tissues. In the intestinal enterocyte, both liver- (LFABP; FABP1) and intestinal FABPs (IFABP; FABP2) are expressed. These proteins display high-affinity binding for long-chain fatty acids (FA) and other hydrophobic ligands; thus, they are believed to be involved with uptake and trafficking of lipids in the intestine. In vitro studies have identified differences in ligand-binding stoichiometry and specificity, and in mechanisms of FA transfer to membranes, and it has been hypothesized that LFABP and IFABP have different functions in the enterocyte. Studies directly comparing LFABP- and IFABP-null mice have revealed markedly different phenotypes, indicating that these proteins indeed have different functions in intestinal lipid metabolism and whole body energy homeostasis. In this review, we discuss the evolving knowledge of the functions of LFABP and IFABP in the intestinal enterocyte.
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Affiliation(s)
- Angela M Gajda
- Department of Nutritional Sciences and Rutgers Center for Lipid Research Rutgers University, New Brunswick, NJ 08901, USA
| | - Judith Storch
- Department of Nutritional Sciences and Rutgers Center for Lipid Research Rutgers University, New Brunswick, NJ 08901, USA.
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7
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Curto LM, Angelani CR, Delfino JM. Intervening in the β-barrel structure of lipid binding proteins: consequences on folding, ligand-binding and aggregation propensity. Prostaglandins Leukot Essent Fatty Acids 2015; 93:37-43. [PMID: 25242388 DOI: 10.1016/j.plefa.2014.08.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Revised: 07/26/2014] [Accepted: 08/01/2014] [Indexed: 02/02/2023]
Abstract
Natural β-folds manage to fold up successfully. By contrast, attempts to dissect fragments or peptides from well folded β-sheet proteins have met with insurmountable difficulties. Here we briefly review selected successful cases of intervention on the well-known scaffold of intestinal fatty acid binding protein (IFABP). Lessons from these examples might set guidelines along the design of proteins belonging to this class. Impact of modifications on topology, binding and aggregation is highlighted. With the aid of abridged variants of IFABP we focus on key structural features responsible for the assembly into oligomeric forms or aggregates.
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Affiliation(s)
- L M Curto
- Department of Biological Chemistry and Institute of Biochemistry and Biophysics (IQUIFIB), School of Pharmacy and Biochemistry, University of Buenos Aires, Junín 956, C1113AAD Buenos Aires, Argentina
| | - C R Angelani
- Department of Biological Chemistry and Institute of Biochemistry and Biophysics (IQUIFIB), School of Pharmacy and Biochemistry, University of Buenos Aires, Junín 956, C1113AAD Buenos Aires, Argentina
| | - J M Delfino
- Department of Biological Chemistry and Institute of Biochemistry and Biophysics (IQUIFIB), School of Pharmacy and Biochemistry, University of Buenos Aires, Junín 956, C1113AAD Buenos Aires, Argentina.
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8
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Matsuoka D, Sugiyama S, Murata M, Matsuoka S. Molecular Dynamics Simulations of Heart-type Fatty Acid Binding Protein in Apo and Holo Forms, and Hydration Structure Analyses in the Binding Cavity. J Phys Chem B 2014; 119:114-27. [DOI: 10.1021/jp510384f] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Daisuke Matsuoka
- JST ERATO, Lipid Active
Structure Project, ‡Department of Chemistry, Graduate
School of Science, and §Project Research Center for Fundamental Science, Osaka University, 1-1
Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Shigeru Sugiyama
- JST ERATO, Lipid Active
Structure Project, ‡Department of Chemistry, Graduate
School of Science, and §Project Research Center for Fundamental Science, Osaka University, 1-1
Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Michio Murata
- JST ERATO, Lipid Active
Structure Project, ‡Department of Chemistry, Graduate
School of Science, and §Project Research Center for Fundamental Science, Osaka University, 1-1
Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Shigeru Matsuoka
- JST ERATO, Lipid Active
Structure Project, ‡Department of Chemistry, Graduate
School of Science, and §Project Research Center for Fundamental Science, Osaka University, 1-1
Machikaneyama, Toyonaka, Osaka 560-0043, Japan
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9
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Sawicki LR, Guerbi MX, Falomir Lockhart LJ, Curto LM, Delfino JM, Córsico B, Franchini GR. Characterization of fatty acid binding and transfer from Δ98Δ, a functional all-β abridged form of IFABP. Biochim Biophys Acta Mol Cell Biol Lipids 2014; 1841:1733-40. [PMID: 25311169 DOI: 10.1016/j.bbalip.2014.09.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Revised: 09/15/2014] [Accepted: 09/30/2014] [Indexed: 11/28/2022]
Abstract
Intestinal fatty acid binding protein (IFABP) is an intracellular lipid binding protein whose specific functions within the cell are still uncertain. An abbreviated version of IFABP encompassing residues 29-126, dubbed Δ98Δ is a stable product of limited proteolysis with clostripain of holo-IFABP. Cumulative evidence shows that Δ98Δ adopts a stable, monomeric and functional fold, with compact core and loose periphery. In agreement with previous results, this abridged variant indicates that the helical domain is-not necessary to preserve the general topology of IFABP's β-barrel and that the helix-turn-helix motif is a fundamental element of the portal region involved in ligand binding and protein-membrane interactions. Results presented here suggest that Δ98Δ binds fatty acids with affinities lower than IFABP but higher than those shown by previous helix-less variants, shows a 'diffusional' fatty acid transfer mechanism and it interacts with artificial membranes. This work highlights the importance of the β-barrel of IFABP for its specific functions.
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10
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Ragona L, Pagano K, Tomaselli S, Favretto F, Ceccon A, Zanzoni S, D'Onofrio M, Assfalg M, Molinari H. The role of dynamics in modulating ligand exchange in intracellular lipid binding proteins. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2014; 1844:1268-78. [PMID: 24768771 DOI: 10.1016/j.bbapap.2014.04.011] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 04/14/2014] [Accepted: 04/16/2014] [Indexed: 11/29/2022]
Abstract
Lipids are essential for many biological processes and crucial in the pathogenesis of several diseases. Intracellular lipid-binding proteins (iLBPs) provide mobile hydrophobic binding sites that allow hydrophobic or amphipathic lipid molecules to penetrate into and across aqueous layers. Thus iLBPs mediate the lipid transport within the cell and participate to a spectrum of tissue-specific pathways involved in lipid homeostasis. Structural studies have shown that iLBPs' binding sites are inaccessible from the bulk, implying that substrate binding should involve a conformational change able to produce a ligand entry portal. Many studies have been reported in the last two decades on iLBPs indicating that their dynamics play a pivotal role in regulating ligand binding and targeted release. The ensemble of reported data has not been reviewed until today. This review is thus intended to summarize and possibly generalize the results up to now described, providing a picture which could help to identify the missing notions necessary to improve our understanding of the role of dynamics in iLBPs' molecular recognition. Such notions would clarify the chemistry of lipid binding to iLBPs and set the basis for the development of new drugs.
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Affiliation(s)
- Laura Ragona
- Laboratorio NMR, Istituto per lo Studio delle Macromolecole (ISMAC), CNR, Via Bassini 15, 20133 Milano, Italy
| | - Katiuscia Pagano
- Laboratorio NMR, Istituto per lo Studio delle Macromolecole (ISMAC), CNR, Via Bassini 15, 20133 Milano, Italy
| | - Simona Tomaselli
- Laboratorio NMR, Istituto per lo Studio delle Macromolecole (ISMAC), CNR, Via Bassini 15, 20133 Milano, Italy
| | - Filippo Favretto
- Dipartimento di Biotecnologie, Università degli Studi di Verona, Strada Le Grazie 15, 37134 Verona, Italy
| | - Alberto Ceccon
- Dipartimento di Biotecnologie, Università degli Studi di Verona, Strada Le Grazie 15, 37134 Verona, Italy
| | - Serena Zanzoni
- Dipartimento di Biotecnologie, Università degli Studi di Verona, Strada Le Grazie 15, 37134 Verona, Italy
| | - Mariapina D'Onofrio
- Dipartimento di Biotecnologie, Università degli Studi di Verona, Strada Le Grazie 15, 37134 Verona, Italy
| | - Michael Assfalg
- Dipartimento di Biotecnologie, Università degli Studi di Verona, Strada Le Grazie 15, 37134 Verona, Italy
| | - Henriette Molinari
- Laboratorio NMR, Istituto per lo Studio delle Macromolecole (ISMAC), CNR, Via Bassini 15, 20133 Milano, Italy.
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11
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de Gerónimo E, Rodriguez Sawicki L, Bottasso Arias N, Franchini GR, Zamarreño F, Costabel MD, Córsico B, Falomir Lockhart LJ. IFABP portal region insertion during membrane interaction depends on phospholipid composition. Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1841:141-50. [PMID: 24148314 DOI: 10.1016/j.bbalip.2013.10.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Revised: 09/24/2013] [Accepted: 10/11/2013] [Indexed: 10/26/2022]
Abstract
Intestinal fatty acid-binding protein (IFABP) is highly expressed in the intestinal epithelium and it belongs to the family of soluble lipid binding proteins. These proteins are thought to participate in most aspects of the biology of lipids, regulating its availability for specific metabolic pathways, targeting and vectorial trafficking of lipids to specific subcellular compartments. The present study is based on the ability of IFABP to interact with phospholipid membranes, and we characterized its immersion into the bilayer's hydrophobic central region occupied by the acyl-chains. We constructed a series of Trp-mutants of IFABP to selectively probe the interaction of different regions of the protein, particularly the elements forming the portal domain that is proposed to regulate the exit and entry of ligands to/from the binding cavity. We employed several fluorescent techniques based on selective quenching induced by soluble or membrane confined agents. The results indicate that the portal region of IFABP penetrates deeply into the phospholipid bilayer, especially when CL-containing vesicles are employed. The orientation of the protein and the degree of penetration were highly dependent on the lipid composition, the superficial net charge and the ionic strength of the medium. These results may be relevant to understand the mechanism of ligand transfer and the specificity responsible for the unique functions of each member of the FABP family.
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Affiliation(s)
- Eduardo de Gerónimo
- Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP), CCT-La Plata (CONICET), Facultad de Cs. Médicas (UNLP), Calle 60 y 120, 1900 La Plata, Argentina
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12
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Ceccon A, D'Onofrio M, Zanzoni S, Longo DL, Aime S, Molinari H, Assfalg M. NMR investigation of the equilibrium partitioning of a water-soluble bile salt protein carrier to phospholipid vesicles. Proteins 2013; 81:1776-91. [DOI: 10.1002/prot.24329] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2013] [Revised: 04/29/2013] [Accepted: 05/09/2013] [Indexed: 11/07/2022]
Affiliation(s)
- Alberto Ceccon
- Department of Biotechnology; University of Verona; 37134 Verona Italy
| | | | - Serena Zanzoni
- Department of Biotechnology; University of Verona; 37134 Verona Italy
| | - Dario Livio Longo
- Department of Molecular Biotechnologies and Health Sciences; Molecular Imaging Center, University of Torino; 10126 Torino Italy
| | - Silvio Aime
- Department of Molecular Biotechnologies and Health Sciences; Molecular Imaging Center, University of Torino; 10126 Torino Italy
| | | | - Michael Assfalg
- Department of Biotechnology; University of Verona; 37134 Verona Italy
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13
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Dyszy F, Pinto APA, Araújo APU, Costa-Filho AJ. Probing the interaction of brain fatty acid binding protein (B-FABP) with model membranes. PLoS One 2013; 8:e60198. [PMID: 23555925 PMCID: PMC3610644 DOI: 10.1371/journal.pone.0060198] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Accepted: 02/21/2013] [Indexed: 12/11/2022] Open
Abstract
Brain fatty acid-binding protein (B-FABP) interacts with biological membranes and delivers polyunsaturated fatty acids (FAs) via a collisional mechanism. The binding of FAs in the protein and the interaction with membranes involve a motif called “portal region”, formed by two small α-helices, A1 and A2, connected by a loop. We used a combination of site-directed mutagenesis and electron spin resonance to probe the changes in the protein and in the membrane model induced by their interaction. Spin labeled B-FABP mutants and lipidic spin probes incorporated into a membrane model confirmed that B-FABP interacts with micelles through the portal region and led to structural changes in the protein as well in the micelles. These changes were greater in the presence of LPG when compared to the LPC models. ESR spectra of B-FABP labeled mutants showed the presence of two groups of residues that responded to the presence of micelles in opposite ways. In the presence of lysophospholipids, group I of residues, whose side chains point outwards from the contact region between the helices, had their mobility decreased in an environment of lower polarity when compared to the same residues in solution. The second group, composed by residues with side chains situated at the interface between the α-helices, experienced an increase in mobility in the presence of the model membranes. These modifications in the ESR spectra of B-FABP mutants are compatible with a less ordered structure of the portal region inner residues (group II) that is likely to facilitate the delivery of FAs to target membranes. On the other hand, residues in group I and micelle components have their mobilities decreased probably as a result of the formation of a collisional complex. Our results bring new insights for the understanding of the gating and delivery mechanisms of FABPs.
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Affiliation(s)
- Fábio Dyszy
- Grupo de Biofísica Molecular Sérgio Mascarenhas, Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, Sao Paulo, Brazil
| | - Andressa P. A. Pinto
- Grupo de Biofísica Molecular Sérgio Mascarenhas, Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, Sao Paulo, Brazil
| | - Ana P. U. Araújo
- Grupo de Biofísica Molecular Sérgio Mascarenhas, Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, Sao Paulo, Brazil
| | - Antonio J. Costa-Filho
- Grupo de Biofísica Molecular Sérgio Mascarenhas, Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, Sao Paulo, Brazil
- Laboratório de Biofísica Molecular, Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Sao Paulo, Brazil
- * E-mail:
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14
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Porfido JL, Alvite G, Silva V, Kennedy MW, Esteves A, Corsico B. Direct interaction between EgFABP1, a fatty acid binding protein from Echinococcus granulosus, and phospholipid membranes. PLoS Negl Trop Dis 2012; 6:e1893. [PMID: 23166848 PMCID: PMC3499409 DOI: 10.1371/journal.pntd.0001893] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2012] [Accepted: 09/21/2012] [Indexed: 12/28/2022] Open
Abstract
Background Growth and maintenance of hydatid cysts produced by Echinococcus granulosus have a high requirement for host lipids for biosynthetic processes, membrane building and possibly cellular and developmental signalling. This requires a high degree of lipid trafficking facilitated by lipid transporter proteins. Members of the fatty acid binding protein (FABP) family have been identified in Echinococcus granulosus, one of which, EgFABP1 is expressed at the tegumental level in the protoscoleces, but it has also been described in both hydatid cyst fluid and secretions of protoscoleces. In spite of a considerable amount of structural and biophysical information on the FABPs in general, their specific functions remain mysterious. Methodology/Principal Findings We have investigated the way in which EgFABP1 may interact with membranes using a variety of fluorescence-based techniques and artificial small unilamellar vesicles. We first found that bacterial recombinant EgFABP1 is loaded with fatty acids from the synthesising bacteria, and that fatty acid binding increases its resistance to proteinases, possibly due to subtle conformational changes induced on EgFABP1. By manipulating the composition of lipid vesicles and the ionic environment, we found that EgFABP1 interacts with membranes in a direct contact, collisional, manner to exchange ligand, involving both ionic and hydrophobic interactions. Moreover, we observed that the protein can compete with cytochrome c for association with the surface of small unilamellar vesicles (SUVs). Conclusions/Significance This work constitutes a first approach to the understanding of protein-membrane interactions of EgFABP1. The results suggest that this protein may be actively involved in the exchange and transport of fatty acids between different membranes and cellular compartments within the parasite. Echinococcus granulosus is the causative agent of hydatidosis, a zoonotic infection that affects humans and livestock, representing a public health and economic burden in many countries. Since the parasites are unable to synthesise most of their lipids de novo, they must acquire them from the host and then deliver them by carrier proteins to specific destinations. E. granulosus produces in abundance proteins of the fatty acid binding protein (FABP) family, one of which, EgFABP1 has been characterised at the structural and ligand binding levels, but it has not been studied in terms of the mechanism of its interaction with membranes. We have investigated the lipid transport properties and protein-membrane interaction characteristics of EgFABP1 by applying biophysical techniques. We found that EgFABP1 interacts with membranes by a mechanism which involves direct contact with them to exchange their cargo. Given that the protein has been found in the secretions of the parasite, the implications of its direct interactions with host membranes should be considered.
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Affiliation(s)
- Jorge L. Porfido
- Instituto de Investigaciones Bioquímicas de La Plata, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata, Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires, Argentina
| | - Gabriela Alvite
- Sección Bioquímica, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Valeria Silva
- Instituto de Investigaciones Bioquímicas de La Plata, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata, Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires, Argentina
| | - Malcolm W. Kennedy
- Institute of Molecular, Cell and Systems Biology, and Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Adriana Esteves
- Sección Bioquímica, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Betina Corsico
- Instituto de Investigaciones Bioquímicas de La Plata, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata, Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires, Argentina
- * E-mail:
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15
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Zamarreño F, Herrera FE, Córsico B, Costabel MD. Similar structures but different mechanisms. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1818:1691-7. [DOI: 10.1016/j.bbamem.2012.03.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 02/27/2012] [Accepted: 03/07/2012] [Indexed: 10/28/2022]
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16
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Falomir-Lockhart LJ, Franchini GR, Guerbi MX, Storch J, Córsico B. Interaction of enterocyte FABPs with phospholipid membranes: clues for specific physiological roles. Biochim Biophys Acta Mol Cell Biol Lipids 2011; 1811:452-9. [PMID: 21539932 DOI: 10.1016/j.bbalip.2011.04.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2010] [Revised: 04/05/2011] [Accepted: 04/06/2011] [Indexed: 10/18/2022]
Abstract
Intestinal and liver fatty acid binding proteins (IFABP and LFABP, respectively) are cytosolic soluble proteins with the capacity to bind and transport hydrophobic ligands between different sub-cellular compartments. Their functions are still not clear but they are supposed to be involved in lipid trafficking and metabolism, cell growth, and regulation of several other processes, like cell differentiation. Here we investigated the interaction of these proteins with different models of phospholipid membrane vesicles in order to achieve further insight into their specificity within the enterocyte. A combination of biophysical and biochemical techniques allowed us to determine affinities of these proteins to membranes, the way phospholipid composition and vesicle size and curvature modulate such interaction, as well as the effect of protein binding on the integrity of the membrane structure. We demonstrate here that, besides their apparently opposite ligand transfer mechanisms, both LFABP and IFABP are able to interact with phospholipid membranes, but the factors that modulate such interactions are different for each protein, further implying different roles for IFABP and LFABP in the intracellular context. These results contribute to the proposed central role of intestinal FABPs in the lipid traffic within enterocytes as well as in the regulation of more complex cellular processes.
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Affiliation(s)
- Lisandro J Falomir-Lockhart
- Instituto de Investigaciones Bioquímicas de La Plata, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata, Argentina
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17
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De Gerónimo E, Hagan RM, Wilton DC, Córsico B. Natural ligand binding and transfer from liver fatty acid binding protein (LFABP) to membranes. Biochim Biophys Acta Mol Cell Biol Lipids 2010; 1801:1082-9. [PMID: 20541621 DOI: 10.1016/j.bbalip.2010.05.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2010] [Revised: 04/27/2010] [Accepted: 05/12/2010] [Indexed: 10/19/2022]
Abstract
Liver fatty acid-binding protein (LFABP) is distinctive among fatty acid-binding proteins because it binds more than one molecule of long-chain fatty acid and a variety of diverse ligands. Also, the transfer of fluorescent fatty acid analogues to model membranes under physiological ionic strength follows a different mechanism compared to most of the members of this family of intracellular lipid binding proteins. Tryptophan insertion mutants sensitive to ligand binding have allowed us to directly measure the binding affinity, ligand partitioning and transfer to model membranes of natural ligands. Binding of fatty acids shows a cooperative mechanism, while acyl-CoAs binding presents a hyperbolic behavior. Saturated fatty acids seem to have a stronger partition to protein vs. membranes, compared to unsaturated fatty acids. Natural ligand transfer rates are more than 200-fold higher compared to fluorescently-labeled analogues. Interestingly, oleoyl-CoA presents a markedly different transfer behavior compared to the rest of the ligands tested, probably indicating the possibility of specific targeting of ligands to different metabolic fates.
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Affiliation(s)
- Eduardo De Gerónimo
- INIBIOLP, Facultad de Ciencias Médicas, Universidad Nacional de La Plata. Calle 60 y 120, 1900, La Plata, Argentina
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18
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Falomir Lockhart LJ, Burgardt NI, Ferreyra RG, Ceolin M, Ermácora MR, Córsico B. Fatty acid transfer from Yarrowia lipolytica sterol carrier protein 2 to phospholipid membranes. Biophys J 2009; 97:248-56. [PMID: 19580762 PMCID: PMC2711373 DOI: 10.1016/j.bpj.2009.03.063] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2008] [Revised: 02/11/2009] [Accepted: 03/03/2009] [Indexed: 11/17/2022] Open
Abstract
Sterol carrier protein 2 (SCP2) is an intracellular protein domain found in all forms of life. It was originally identified as a sterol transfer protein, but was recently shown to also bind phospholipids, fatty acids, and fatty-acyl-CoA with high affinity. Based on studies carried out in higher eukaryotes, it is believed that SCP2 targets its ligands to compartmentalized intracellular pools and participates in lipid traffic, signaling, and metabolism. However, the biological functions of SCP2 are incompletely characterized and may be different in microorganisms. Herein, we demonstrate the preferential localization of SCP2 of Yarrowia lipolytica (YLSCP2) in peroxisome-enriched fractions and examine the rate and mechanism of transfer of anthroyloxy fatty acid from YLSCP2 to a variety of phospholipid membranes using a fluorescence resonance energy transfer assay. The results show that fatty acids are transferred by a collision-mediated mechanism, and that negative charges on the membrane surface are important for establishing a "collisional complex". Phospholipids, which are major constituents of peroxisome and mitochondria, induce special effects on the rates of transfer. In conclusion, YLSCP2 may function as a fatty acid transporter with some degree of specificity, and probably diverts fatty acids to the peroxisomal metabolism.
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Affiliation(s)
- Lisandro J. Falomir Lockhart
- Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP), Facultad de Ciencias Médicas, Universidad Nacional de La Plata (UNLP), La Plata, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Noelia I. Burgardt
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
- Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes (UNQ), Bernal, Argentina
| | - Raúl G. Ferreyra
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
- Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes (UNQ), Bernal, Argentina
| | - Marcelo Ceolin
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
- Instituto de Físico-Química Teórica y Aplicada (INIFTA), Universidad Nacional de La Plata, La Plata, Argentina
| | - Mario R. Ermácora
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
- Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes (UNQ), Bernal, Argentina
| | - Betina Córsico
- Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP), Facultad de Ciencias Médicas, Universidad Nacional de La Plata (UNLP), La Plata, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
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