Structural Features of EDG1 Receptor‐Ligand Complexes Revealed by Computational Modeling and Mutagenesis

Parrill, Abby L.; Baker, Daniel L.; Wang, De-An; Fischer, David J.; Bautista, Debra L.; Brocklyn, James Van; Spiegel, Sarah; Tigyi, Gábor

doi:10.1111/j.1749-6632.2000.tb06573.x

Cited by 25 publications

(23 citation statements)

References 21 publications

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“…5C). Arg 124 is conserved in all Edg family G protein -coupled receptors and is critical for interaction with LPA or sphingosine-1-phosphate (52,53). Unlike LPA 1 , overexpression of M 2 mAChRs did not alter p53-dependent transcription and stimulation of these cells with the muscarinic agonist carbachol (10 mmol/L) actually enhanced p53-mediated transcription.…”

Section: The Proportion Of Cells Showing P21mentioning

confidence: 98%

Lysophosphatidic Acid Decreases the Nuclear Localization and Cellular Abundance of the p53 Tumor Suppressor in A549 Lung Carcinoma Cells

Murph

Hurst-Kennedy

Newton

et al. 2007

Molecular Cancer Research

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Lysophosphatidic acid (LPA) is a bioactive lipid that promotes cancer cell proliferation and motility through activation of cell surface G protein -coupled receptors. Here, we provide the first evidence that LPA reduces the cellular abundance of the tumor suppressor p53 in A549 lung carcinoma cells, which express endogenous LPA receptors. The LPA effect depends on increased proteasomal degradation of p53 and it results in a corresponding decrease in p53-mediated transcription. Inhibition of phosphatidylinositol 3-kinase protected cells from the LPA-induced reduction of p53, which implicates this signaling pathway in the mechanism of LPA-induced loss of p53. LPA partially protected A549 cells from actinomycin D induction of both apoptosis and increased p53 abundance. Expression of LPA 1 , LPA 2 , and LPA 3 receptors in HepG2 hepatoma cells, which normally do not respond to LPA, also decreased p53 expression and p53-dependent transcription. In contrast, neither inactive LPA 1 (R124A) nor another G i -coupled receptor, the M 2 muscarinic acetylcholine receptor, reduced p53-dependent transcription in HepG2 cells. These results identify p53 as a target of LPA action and provide a new dimension for understanding how LPA stimulates cancer cell division, protects against apoptosis, and thereby promotes tumor progression.

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Section: The Proportion Of Cells Showing P21mentioning

confidence: 98%

Lysophosphatidic Acid Decreases the Nuclear Localization and Cellular Abundance of the p53 Tumor Suppressor in A549 Lung Carcinoma Cells

Murph

Hurst-Kennedy

Newton

et al. 2007

Molecular Cancer Research

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“…A validated computational model of S1P 1 was developed that successfully identified residues in TM3 and TM7 of S1P 1 that participated in ligand binding. A critical role for residues R3.28, E3.29, and R7.34 of S1P 1 in ligand binding and receptor activation was experimentally confirmed using a sitedirected mutagenesis strategy (20). Later studies determined that in S1P 4 the residues R3.28, E3.29, W4.64, and K5.38 were critical for ligand binding and receptor activation (21), whereas K5.38 was not essential in S1P 1 (22).…”

mentioning

confidence: 99%

Subtype-specific Residues Involved in Ligand Activation of the Endothelial Differentiation Gene Family Lysophosphatidic Acid Receptors

Valentine

Fells

Perygin

et al. 2008

Journal of Biological Chemistry

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Lysophosphatidic acid (LPA) is a ligand for three endothelial differentiation gene family G protein-coupled receptors, LPA 1-3 . We performed computational modeling-guided mutagenesis of conserved residues in transmembrane domains 3, 4, 5, and 7 of LPA 1-3 predicted to interact with the glycerophosphate motif of LPA C18:1. The mutants were expressed in RH7777 cells, and the efficacy (E max ) and potency (EC 50 ) of LPA-elicited Ca 2؉ transients were measured. Mutation to alanine of R3.28 universally decreased both the efficacy and potency in LPA 1-3 and eliminated strong ionic interactions in the modeled LPA complexes. The alanine mutation at Q3.29 decreased modeled interactions and activation in LPA 1 and LPA 2 more than in LPA 3 . The mutation W4.64A had no effect on activation and modeled LPA interaction of LPA 1 and LPA 2 but reduced the activation and modeled interactions of LPA 3 . The R5.38A mutant of LPA 2 and R5.38N mutant of LPA 3 showed diminished activation by LPA; however, in LPA 1 the D5.38A mutation did not, and mutation to arginine enhanced receptor activation. In LPA 2 , K7.36A decreased the potency of LPA; in LPA 1 this same mutation increased the E max . In LPA 3 , R7.36A had almost no effect on receptor activation; however, the mutation K7.35A increased the EC 50 in response to LPA 10-fold. In LPA 1-3 , the mutation Q3.29E caused a modest increase in EC 50 in response to LPA but caused the LPA receptors to become more responsive to sphingosine 1-phosphate (S1P). Surprisingly micromolar concentrations of S1P activated the wild type LPA 2 and LPA 3 receptors, indicating that S1P may function as a weak agonist of endothelial differentiation gene family LPA receptors. Lysophosphatidic acid (LPA)2 and sphingosine 1-phosphate (S1P) are structurally related lysophospholipid growth factors that mediate a variety of cellular effects, including regulation of cellular proliferation, survival, migration, and morphology (1-3). LPA has been shown to play an important role in a variety of diseases including ovarian cancer, prostate cancer, breast cancer, and cardiovascular disease (4 -14). Many of the biological effects of LPA are mediated through cell surface receptors of the endothelial differentiation gene (EDG) family of G protein-coupled receptors (GPCRs).The EDG family of GPCRs includes eight closely related genes that show the conserved GPCR topology of an extracellular amino terminus followed by seven ␣-helical transmembrane domains (TMs) (15). Three of these genes (LPA 1-3 ) are cellular receptors for LPA and share 55% overall homology in humans. The other five (S1P 1-5 ) are cellular receptors for S1P and share 50% homology in humans. The two subclusters are 35% homologous with each other. The transmembrane domains of human LPA 1-3 where ligand binding takes place show 81% homology with each other. LPA has also been shown to elicit cellular responses through binding to three non-EDG family GPCRs, p2y9/LPA 4 , GPR92/LPA 5 , and GPR87/LPA 6 , which are more closely related to the purinoreceptor clus...

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“…AGP is shown as a spacefilling model, select residues are shown as stick models. Modeled location of amino acids subjected to site-directed mutagenesis [40,84,88,92,93,[95][96][97] in the EDG receptor GPCR family mapped onto the S1P 1 receptor model [40]. Blue ribbons indicate sites not subjected to mutational analysis in any member of the EDG family.…”

Section: Discussionmentioning

confidence: 99%

“…Modeling studies have been applied to study lysophospholipid recognition by the EDG-family GPCR, LPA 1-3 [84][85][86][87][88][89][90] and S1P [1][2][3][4][5] [40,84,[91][92][93][94][95][96][97][98][99], the nuclear receptor PPARγ [100], and the enzyme ATX [42].…”

Section: Modeling Studiesmentioning

confidence: 99%

“…The earliest modeling studies of S1P interactions with S1P 1 [94][95][96] were reported concurrently with the first atomicresolution crystallographic structure of rhodopsin. Even without a high-resolution crystal structure to provide a structural template, key ion-pairing interactions from amino acids R3.28, E3.29 and R7.34 to the phosphate and ammonium moieties in the S1P headgroup were proposed.…”

Section: Modeling Lysophospholipid Interactions With Gpcr-mentioning

confidence: 99%

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Lysophospholipid interactions with protein targets

Parrill

2008

Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biolog

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SummaryBioactive lysophospholipids include lysophosphatidic acid (LPA), sphingosine 1-phosphate (S1P), cyclic-phosphatidic acid (CPA) and alkyl glycerolphosphate (AGP). These lipid mediators stimulate a variety of responses that include cell survival, proliferation, migration, invasion, wound healing, and angiogenesis. Responses to lysophospholipids depend upon interactions with biomolecular targets in the G protein-coupled receptor (GPCR) and nuclear receptor families, as well as enzymes. Our current understanding of lysophospholipid interactions with these targets is based on a combination of lysophospholipid analog structure activity relationship studies as well as more direct structural characterization techniques such as X-ray crystallography, nuclear magnetic resonance (NMR) spectroscopy, and experimentally-validated molecular modeling. The direct structural characterization studies are the focus of this review, and provide the insight necessary to stimulate structure-based therapeutic lead discovery efforts in the future.

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Structural Features of EDG1 Receptor‐Ligand Complexes Revealed by Computational Modeling and Mutagenesis

Cited by 25 publications

References 21 publications

Lysophosphatidic Acid Decreases the Nuclear Localization and Cellular Abundance of the p53 Tumor Suppressor in A549 Lung Carcinoma Cells

Lysophosphatidic Acid Decreases the Nuclear Localization and Cellular Abundance of the p53 Tumor Suppressor in A549 Lung Carcinoma Cells

Subtype-specific Residues Involved in Ligand Activation of the Endothelial Differentiation Gene Family Lysophosphatidic Acid Receptors

Lysophospholipid interactions with protein targets

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