Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Crystallographic study of FABP5 as an intracellular endocannabinoid transporter.

ABSTRACT: In addition to binding intracellular fatty acids, fatty-acid-binding proteins (FABPs) have recently been reported to also transport the endocannabinoids anandamide (AEA) and 2-arachidonoylglycerol (2-AG), arachidonic acid derivatives that function as neurotransmitters and mediate a diverse set of physiological and psychological processes. To understand how the endocannabinoids bind to FABPs, the crystal structures of FABP5 in complex with AEA, 2-AG and the inhibitor BMS-309403 were determined. These ligands are shown to interact primarily with the substrate-binding pocket via hydrophobic interactions as well as a common hydrogen bond to the Tyr131 residue. This work advances our understanding of FABP5-endocannabinoid interactions and may be useful for future efforts in the development of small-molecule inhibitors to raise endocannabinoid levels.

SUBMITTER: Sanson B

PROVIDER: S-EPMC3940194 | biostudies-literature | 2014 Feb

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Crystallographic study of FABP5 as an intracellular endocannabinoid transporter.

Sanson Benoît B Wang Tao T Sun Jing J Wang Liqun L Kaczocha Martin M Ojima Iwao I Deutsch Dale D Li Huilin H

Acta crystallographica. Section D, Biological crystallography 20140129 Pt 2

In addition to binding intracellular fatty acids, fatty-acid-binding proteins (FABPs) have recently been reported to also transport the endocannabinoids anandamide (AEA) and 2-arachidonoylglycerol (2-AG), arachidonic acid derivatives that function as neurotransmitters and mediate a diverse set of physiological and psychological processes. To understand how the endocannabinoids bind to FABPs, the crystal structures of FABP5 in complex with AEA, 2-AG and the inhibitor BMS-309403 were determined. T ...[more]

PMID: 24531463

Similar Datasets

FABP5 deletion in nociceptors augments endocannabinoid signaling and suppresses TRPV1 sensitization and inflammatory pain.

Project description:The endocannabinoid anandamide (AEA) produces antinociceptive effects by activating cannabinoid receptor 1 (CB1). However, AEA also serves as an agonist at transient receptor potential vanilloid receptor 1 (TRPV1) in nociceptive sensory neurons, which may exacerbate pain. This potential functional duality is highlighted by the failure of an inhibitor of the AEA catabolic enzyme fatty acid amide hydrolase (FAAH) to afford pain relief in a clinical trial. Consequently, it remains to be determined whether elevating AEA levels in nociceptors leads to antinociceptive or pro-nociceptive effects. Fatty acid binding protein 5 (FABP5) is an intracellular carrier that mediates AEA transport to FAAH for inactivation. Leveraging the abundant expression of FABP5 in TRPV1+ nociceptors, we employed a conditional knockout strategy to demonstrate that FABP5 deletion in nociceptors augments AEA levels, resulting in the emergence of antinociceptive effects mediated by CB1. Mechanistically, FABP5 deletion suppresses inflammation- and nerve growth factor-mediated TRPV1 sensitization via CB1, an effect mediated by calcineurin. Unexpectedly, inhibition of FAAH failed to blunt TRPV1 sensitization, uncovering functionally distinct outputs resulting from FABP5 and FAAH inhibition. Collectively, our results demonstrate that FABP5 serves a key role in governing endocannabinoid signaling in nociceptors to disrupt TRPV1 sensitization and pain, and position FABP5 as a therapeutic target for the development of analgesics.

| S-EPMC9163147 | biostudies-literature

Identification of intracellular carriers for the endocannabinoid anandamide.

Project description:The endocannabinoid anandamide (arachidonoyl ethanolamide, AEA) is an uncharged neuromodulatory lipid that, similar to many neurotransmitters, is inactivated through its cellular uptake and subsequent catabolism. AEA is hydrolyzed by fatty acid amide hydrolase (FAAH), an enzyme localized on the endoplasmic reticulum. In contrast to most neuromodulators, the hydrophilic cytosol poses a diffusional barrier for the efficient delivery of AEA to its site of catabolism. Therefore, AEA likely traverses the cytosol with the assistance of an intracellular carrier that increases its solubility and rate of diffusion. To study this process, AEA uptake and hydrolysis were examined in COS-7 cells expressing FAAH restricted to the endoplasmic reticulum, mitochondria, or the Golgi apparatus. AEA hydrolysis was detectable at the earliest measurable time point (3 seconds), suggesting that COS-7 cells, normally devoid of an endocannabinoid system, possess an efficient cytosolic trafficking mechanism for AEA. Three fatty acid binding proteins (FABPs) known to be expressed in brain were examined as possible intracellular AEA carriers. AEA uptake and hydrolysis were significantly potentiated in N18TG2 neuroblastoma cells after overexpression of FABP5 or FABP7, but not FABP3. Similar results were observed in COS-7 cells stably expressing FAAH. Consistent with the roles of FABP as AEA carriers, administration of the competitive FABP ligand oleic acid or the selective non-lipid FABP inhibitor BMS309403 attenuated AEA uptake and hydrolysis by approximately 50% in N18TG2 and COS-7 cells. Taken together, FABPs represent the first proteins known to transport AEA from the plasma membrane to FAAH for inactivation and may therefore be novel pharmacological targets.

| S-EPMC2669397 | biostudies-literature

Intracellular zinc inhibits KCC2 transporter activity.

Project description:We found that K(+)/Cl(-) co-transporter 2 (KCC2) activity, monitored with wide-field fluorescence, was inhibited by intracellular Zn(2+), a major component of neuronal injury. Zn(2+)-mediated KCC2 inhibition produced a depolarizing shift of GABA(A) reversal potentials in rat cortical neurons. Moreover, oxygen-glucose deprivation attenuated KCC2 activity in a Zn(2+)-dependent manner. The link between Zn(2+) and KCC2 activity provides a previously unknown target for neuroprotection and may be important in activity-dependent regulation of inhibitory synaptic transmission.

| S-EPMC2737597 | biostudies-literature

ATP binding cassette transporter G1 (ABCG1) is an intracellular sterol transporter.

Project description:Four members of the mammalian ATP binding cassette (ABC) transporter G subfamily are thought to be involved in transmembrane (TM) transport of sterols. The residues responsible for this transport are unknown. The mechanism of action of ABCG1 is controversial and it has been proposed to act at the plasma membrane to facilitate the efflux of cellular sterols to exogenous high-density lipoprotein (HDL). Here we show that ABCG1 function is dependent on localization to intracellular endosomes. Importantly, localization to the endosome pathway distinguishes ABCG1 and/or ABCG4 from all other mammalian members of this superfamily, including other sterol transporters. We have identified critical residues within the TM domains of ABCG1 that are both essential for sterol transport and conserved in some other members of the ABCG subfamily and/or the insulin-induced gene 2 (INSIG-2). Our conclusions are based on studies in which (i) biotinylation of peritoneal macrophages showed that endogenous ABCG1 is intracellular and undetectable at the cell surface, (ii) a chimeric protein containing the TM of ABCG1 and the cytoplasmic domains of the nonsterol transporter ABCG2 is both targeted to endosomes and functional, and (iii) ABCG1 colocalizes with multiple proteins that mark late endosomes and recycling endosomes. Mutagenesis studies identify critical residues in the TM domains that are important for ABCG1 to alter sterol efflux, induce sterol regulatory element binding protein-2 (SREBP-2) processing, and selectively attenuate the oxysterol-mediated repression of SREBP-2 processing. Our data demonstrate that ABCG1 is an intracellular sterol transporter that localizes to endocytic vesicles to facilitate the redistribution of specific intracellular sterols away from the endoplasmic reticulum (ER).

| S-EPMC3241749 | biostudies-literature

Cigarette smoke inhibits LPS-induced FABP5 expression by preventing c-Jun binding to the FABP5 promoter.

Project description:Cigarette smoking is the primary cause of chronic obstructive pulmonary disease (COPD) with repeated and sustained infections linked to disease pathogenesis and exacerbations. The airway epithelium constitutes the first line of host defense against infection and is known to be impaired in COPD. We have previously identified Fatty Acid Binding Protein 5 (FABP5) as an important anti-inflammatory player during respiratory infections and showed that overexpression of FABP5 in primary airway epithelial cells protects against bacterial infection and inflammation. While cigarette smoke down regulates FABP5 expression, its mechanism remains unknown. In this report, we have identified three putative c-Jun binding sites on the FABP5 promoter and show that cigarette smoke inhibits the binding of c-Jun to its consensus sequence and prevents LPS-induced FABP5 expression. Using chromatin immunoprecipitation, we have determined that c-Jun binds the FABP5 promoter when stimulated with LPS but the presence of cigarette smoke greatly reduces this binding. Furthermore, cigarette smoke or a mutation in the c-Jun binding site inhibits LPS-induced FABP5 promoter activity. These data demonstrate that cigarette smoke interferes with FABP5 expression in response to bacterial infection. Thus, functional activation of FABP5 may be a new therapeutic strategy when treating COPD patients suffering from exacerbations.

| S-EPMC5436865 | biostudies-literature

Crystallization and preliminary X-ray crystallographic analysis of the curli transporter CsgG.

Project description:Gram-negative bacteria have eight known protein secretion systems. The type-VIII secretion system, also known as the curli biosynthesis system, is responsible for the formation of aggregative fibres known in Escherichia coli as curli. Curli are extracellular proteinaceous fibres primarily involved in bacterial biofilm formation and attachment to nonbiotic surfaces. The secretion of curli subunits depends on a dedicated lipoprotein, CsgG, which is found to form an oligomeric secretion channel in the outer membrane. A nonlipidated mutant of CsgG was expressed and crystallized in a soluble form. The crystals diffracted to 3.15 Å resolution and belong to space group P1 with a unit cell containing a predicted 16 molecules per asymmetric unit.

| S-EPMC3855717 | biostudies-literature

Regulation of Alr1 Mg transporter activity by intracellular magnesium.

Project description:Mg homeostasis is critical to eukaryotic cells, but the contribution of Mg transporter activity to homeostasis is not fully understood. In yeast, Mg uptake is primarily mediated by the Alr1 transporter, which also allows low affinity uptake of other divalent cations such as Ni(2+), Mn(2+), Zn(2+) and Co(2+). Using Ni(2+) uptake to assay Alr1 activity, we observed approximately nine-fold more activity under Mg-deficient conditions. The mnr2 mutation, which is thought to block release of vacuolar Mg stores, was associated with increased Alr1 activity, suggesting Alr1 was regulated by intracellular Mg supply. Consistent with a previous report of the regulation of Alr1 expression by Mg supply, Mg deficiency and the mnr2 mutation both increased the accumulation of a carboxy-terminal epitope-tagged version of the Alr1 protein (Alr1-HA). However, Mg supply had little effect on ALR1 promoter activity or mRNA levels. In addition, while Mg deficiency caused a seven-fold increase in Alr1-HA accumulation, the N-terminally tagged and untagged Alr1 proteins increased less than two-fold. These observations argue that the Mg-dependent accumulation of the C-terminal epitope-tagged protein was primarily an artifact of its modification. Plasma membrane localization of YFP-tagged Alr1 was also unaffected by Mg supply, indicating that a change in Alr1 location did not explain the increased activity we observed. We conclude that variation in Alr1 protein accumulation or location does not make a substantial contribution to its regulation by Mg supply, suggesting Alr1 activity is directly regulated via as yet unknown mechanisms.

| S-EPMC3125163 | biostudies-literature

FABP5 as a possible biomarker in atopic march: FABP5-induced Th17 polarization, both in mouse model and human samples.

Project description:BACKGROUND:While the incidence of patients with atopic dermatitis (AD) with atopic march (AM) showing respiratory allergy is steadily rising, the pathomechanism is still unknown. There are currently no biomarkers to predict progression of AM. METHODS:To explore the mechanism of AM, patients with AD and AM and healthy controls were recruited and RNA microarray, flow cytometry, quantitative real-time polymerase chain reaction, and immunofluorescence staining were performed. We also co-cultured dendritic cells and CD4+T cells with various Dermatophagoides farinae allergen fractions. Cytokine levels were evaluated using enzyme-linked immunosorbent assay. FINDINGS:Both fatty-acid-binding protein 5 (FABP5) and Th17-related genes were more highly expressed in AM. FABP5 knockdown significantly decreased Th17-inducing cytokines in keratinocytes and IL-17A in T cells from AM patients. Further confirmation was obtained using an AM mice model compared to mice without AM. Der f 1, a major D. farinae allergen, increased FABP5 and IL-17A expression in T cells from AM patients. Higher serum FABP5 levels from AM patients were positively correlated with serum IL-17A levels. INTERPRETATION:FABP5 expression, possibly enhanced by higher epicutaneous and respiratory sensitization to Der f 1, may directly promote Th17 responses in AD patients with AM. Thus, AM progression can be explained by Th17 reaction induced by FABP5. FABP5 was identified as a potential biomarker in AM. FUNDING:This study was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (Ministry of Science and ICT; No. NRF-2017R1A2B4009568), grants of the Korean Health Technology R&D Project, Ministry for Health, Welfare & Family Affairs, and the Republic of Korea (HI13C0010, HI14C1324, HI14C1799).

| S-EPMC7387782 | biostudies-literature

Sumoylation of the astroglial glutamate transporter EAAT2 governs its intracellular compartmentalization.

Project description:EAAT2 is a predominantly astroglial glutamate transporter responsible for the majority of synaptic glutamate clearance in the mammalian central nervous system (CNS). Its dysfunction has been linked with many neurological disorders, including amyotrophic lateral sclerosis (ALS). Decreases in EAAT2 expression and function have been implicated in causing motor neuron excitotoxic death in ALS. Nevertheless, increasing EAAT2 expression does not significantly improve ALS phenotype in mouse models or in clinical trials. In the SOD1-G93A mouse model of inherited ALS, the cytosolic carboxy-terminal domain is cleaved from EAAT2, conjugated to SUMO1, and accumulated in astrocytes where it triggers astrocyte-mediated neurotoxic effects as disease progresses. However, it is not known whether this fragment is sumoylated after cleavage or if full-length EAAT2 is already sumoylated prior to cleavage as part of physiological regulation. In this study, we show that a fraction of full-length EAAT2 is constitutively sumoylated in primary cultures of astrocytes in vitro and in the CNS in vivo. Furthermore, the extent of sumoylation of EAAT2 does not change during the course of ALS in the SOD1-G93A mouse and is not affected by the expression of ALS-causative mutant SOD1 proteins in astrocytes in vitro, indicating that EAAT2 sumoylation is not driven by pathogenic mechanisms. Most interestingly, sumoylated EAAT2 localizes to intracellular compartments, whereas non-sumoylated EAAT2 resides on the plasma membrane. In agreement, promoting desumoylation in primary astrocytes causes increased EAAT2-mediated glutamate uptake. These findings could have implications for optimizing therapeutic approaches aimed at increasing EAAT2 activity in the dysfunctional or diseased CNS.

| S-EPMC4061158 | biostudies-literature

Aphid amino acid transporter regulates glutamine supply to intracellular bacterial symbionts.

Project description:Endosymbiotic associations have played a major role in evolution. However, the molecular basis for the biochemical interdependence of these associations remains poorly understood. The aphid-Buchnera endosymbiosis provides a powerful system to elucidate how these symbioses are regulated. In aphids, the supply of essential amino acids depends on an ancient nutritional symbiotic association with the gamma-proteobacterium Buchnera aphidicola. Buchnera cells are densely packed in specialized aphid bacteriocyte cells. Here we confirm that five putative amino acid transporters are highly expressed and/or highly enriched in Acyrthosiphon pisum bacteriocyte tissues. When expressed in Xenopus laevis oocytes, two bacteriocyte amino acid transporters displayed significant levels of glutamine uptake, with transporter ACYPI001018, LOC100159667 (named here as Acyrthosiphon pisum glutamine transporter 1, ApGLNT1) functioning as the most active glutamine transporter. Transporter ApGLNT1 has narrow substrate selectivity, with high glutamine and low arginine transport capacity. Notably, ApGLNT1 has high binding affinity for arginine, and arginine acts as a competitive inhibitor for glutamine transport. Using immunocytochemistry, we show that ApGLNT1 is localized predominantly to the bacteriocyte plasma membrane, a location consistent with the transport of glutamine from A. pisum hemolymph to the bacteriocyte cytoplasm. On the basis of functional transport data and localization, we propose a substrate feedback inhibition model in which the accumulation of the essential amino acid arginine in A. pisum hemolymph reduces the transport of the precursor glutamine into bacteriocytes, thereby regulating amino acid biosynthesis in the bacteriocyte. Structural similarities in the arrangement of hosts and symbionts across endosymbiotic systems suggest that substrate feedback inhibition may be mechanistically important in other endosymbioses.

| S-EPMC3890774 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data