scholarly journals Alteration of a Single Amino Acid in Peroxisome Proliferator-Activated Receptor-α (PPARα) Generates a PPARδ Phenotype

2000 ◽  
Vol 14 (5) ◽  
pp. 733-740 ◽  
Author(s):  
Ichiro Takada ◽  
Ruth T. Yu ◽  
H. Eric Xu ◽  
Millard H. Lambert ◽  
Valerie G. Montana ◽  
...  
Keyword(s):  
Amino Acid ◽  
Nuclear Receptors ◽  
Site Directed Mutagenesis ◽  
Single Amino Acid ◽  
Peroxisome Proliferator ◽  
Transcriptional Responses ◽  
Peroxisome Proliferator Activated Receptor ◽  
Single Amino Acid Change ◽  
Close Relationship ◽  
Peroxisome Proliferator Activated Receptors

Abstract Three pharmacologically important nuclear receptors, the peroxisome proliferator-activated receptors (PPARs α,γ , and δ), mediate key transcriptional responses involved in lipid homeostasis. The PPARα and γ subtypes are well conserved from Xenopus to man, but the β/δ subtypes display substantial species variations in both structure and ligand activation profiles. Characterization of the avian cognates revealed a close relationship between chick (c) α and γ subtypes to their mammalian counterparts, whereas the third chicken subtype was intermediate to Xenopus (x) β and mammalian δ, establishing that β and δ are orthologs. Like xPPARβ, cPPARβ responded efficiently to hypolipidemic compounds that fail to activate the human counterpart. This provided the opportunity to address the pharmacological problem as to how drug selectivity is achieved and the more global evolutionary question as to the minimal changes needed to generate a new class of receptor. X-ray crystallography and chimeric analyses combined with site-directed mutagenesis of avian and mammalian cognates revealed that a Met to Val change at residue 417 was sufficient to switch the human and chick phenotype. These results establish that the genetic drive to evolve a novel and functionally selectable receptor can be modulated by a single amino acid change and suggest how nuclear receptors can accommodate natural variation in species physiology.

scholarly journals Single amino acid changes in the mumps virus haemagglutinin–neuraminidase and polymerase proteins are associated with neuroattenuation

2009 ◽  
Vol 90 (7) ◽  
pp. 1741-1747 ◽  
Author(s):  
Tahir H. Malik ◽  
Candie Wolbert ◽  
Laura Nerret ◽  
Christian Sauder ◽  
Steven Rubin
Keyword(s):  
Amino Acid ◽  
Clinical Isolate ◽  
Amino Acid Change ◽  
Mumps Virus ◽  
Site Directed Mutagenesis ◽  
Single Amino Acid ◽  
Supporting Evidence ◽  
L Protein ◽  
Single Amino Acid Change

It has previously been shown that three amino acid changes, one each in the fusion (F; Ala/Thr-91→Thr), haemagglutinin–neuraminidase (HN; Ser-466→Asn) and polymerase (L; Ile-736→Val) proteins, are associated with attenuation of a neurovirulent clinical isolate of mumps virus (88-1961) following serial passage in vitro. Here, using full-length cDNA plasmid clones and site-directed mutagenesis, it was shown that the single amino acid change in the HN protein and to a lesser extent, the change in the L protein, resulted in neuroattenuation, as assessed in rats. The combination of both amino acid changes caused neuroattenuation of the virus to levels previously reported for the clinical isolate following attenuation in vitro. The amino acid change in the F protein, despite having a dramatic effect on protein function in vitro, was previously shown to not be involved in the observed neuroattenuation, highlighting the importance of conducting confirmatory in vivo studies. This report provides additional supporting evidence for the role of the HN protein as a virulence factor and, as far as is known, is the first report to associate an amino acid change in the L protein with mumps virus neuroattenuation.

scholarly journals Structural characterization of human aryl sulphotransferases

1999 ◽  
Vol 337 (2) ◽  
pp. 337-343 ◽  
Author(s):  
Lulu A. BRIX ◽  
Ronald G. DUGGLEBY ◽  
Andrea GAEDIGK ◽  
Michael E. McMANUS
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Change ◽  
Substrate Binding ◽  
Site Directed Mutagenesis ◽  
Single Amino Acid ◽  
Wild Type ◽  
Substrate Specificities ◽  
Loop Region ◽  
Single Amino Acid Change

Human aryl sulphotransferase (HAST) 1, HAST3, HAST4 and HAST4v share greater than 90% sequence identity, but vary markedly in their ability to catalyse the sulphonation of dopamine and p-nitrophenol. In order to investigate the amino acid(s) involved in determining differing substrate specificities of HASTs, a range of chimaeric HAST proteins were constructed. Analysis of chimaeric substrate specificities showed that enzyme affinities are mainly determined within the N-terminal end of each HAST protein, which includes two regions of high sequence divergence, termed Regions A (amino acids 44–107) and B (amino acids 132–164). To investigate the substrate-binding sites of HASTs further, site-directed mutagenesis was performed on HAST1 to change 13 individual residues within these two regions to the HAST3 equivalent. A single amino acid change in HAST1 (A146E) was able to change the specificity for p-nitrophenol to that of HAST3. The substrate specificity of HAST1 towards dopamine could not be converted into that of HAST3 with a single amino acid change. However, compared with wild-type HAST1, a number of the mutations resulted in interference with substrate binding, as shown by elevated Ki values towards the co-substrate 3´-phosphoadenosine 5´-phosphosulphate, and in some cases loss of activity towards dopamine. These findings suggest that a co-ordinated change of multiple amino acids in HAST proteins is needed to alter the substrate specificities of these enzymes towards dopamine, whereas a single amino acid at position 146 determines p-nitrophenol affinity. A HAST1 mutant was constructed to express a protein with four amino acids deleted (P87–P90). These amino acids were hypothesized to correspond to a loop region in close proximity to the substrate-binding pocket. Interestingly, the protein showed substrate specificities more similar to wild-type HAST3 than HAST1 and indicates an important role of these amino acids in substrate binding.

The Role of Peroxisome Proliferator-Activated Receptor in Addiction: A Novel Drug Target

2021 ◽  
Vol 21 ◽  
Author(s):  
Carla Quiroga ◽  
Juan José Barberena ◽  
Jocelyne Alcaraz-Silva ◽  
Sérgio Machado ◽  
Claudio Imperatori ◽  
...  
Keyword(s):  
Nuclear Receptors ◽  
Acid Oxidation ◽  
Critical Element ◽  
Peroxisome Proliferator ◽  
Addictive Behaviors ◽  
Health Issues ◽  
Peroxisome Proliferator Activated Receptor ◽  
Peroxisome Proliferator Activated Receptors ◽  
Novel Drug

: The peroxisome proliferator activated receptors (PPARs) are a superfamily of well-recognized ligand-binding nuclear receptors comprising three isoforms: PPARα, PPARγ, and PPARβ/δ. In response to endogenous lipid messengers, PPARs trigger the transcription of genes related to a wider spectrum of physiological phenomena, including fatty acid oxidation, inflammation, and adipogenesis among many others. Thus, the importance of PPARs as putative protective therapy in health issues has increased the interest in studying these nuclear receptors, including the management of neurodegenerative disorders, multiple sclerosis, and likely addiction. In recent years, several pieces of evidence from animal models have demonstrated the promising role of PPARs as a critical element for interventions in addictive behaviors by reducing the reinforcing properties of addictive substances such as alcohol. However, there is a lack of data in scope and has so far been unexplored the function of PPARs in additional drugs such as cannabis, opioids, methamphetamine, or cocaine. Similar scenario has been found for the management of binge-type eating disorders. Thus, here we review recent advances in understanding the relevance of the PPAR controlling addiction.

scholarly journals A Single Amino Acid Change in Nramp6 from Sedum Alfredii Hance Affects Cadmium Accumulation

2020 ◽  
Vol 21 (9) ◽  
pp. 3169
Author(s):  
Zhuchou Lu ◽  
Shuangshuang Chen ◽  
Xiaojiao Han ◽  
Jin Zhang ◽  
Guirong Qiao ◽  
...  
Keyword(s):  
Amino Acid ◽  
Cadmium Accumulation ◽  
Site Directed Mutagenesis ◽  
Natural Resistance ◽  
Single Amino Acid ◽  
Sedum Alfredii ◽  
Transport Activity ◽  
Sequence Comparisons ◽  
Single Amino Acid Change ◽  
Cd Transport

SaNramp6 in Sedum alfredii encodes a membrane-localized metal transporter. We isolated the SaNramp6h allele from the hyperaccumulating ecotype (HE) of S. alfredii. When this allele was expressed in transgenic yeast and Arabidopsis thaliana, it enhanced their cadmium (Cd) sensitivity by increased Cd transport and accumulation. We isolated another allele, SaNramp6n, from a nonhyperaccumulating ecotype (NHE) of S. alfredii. Amino acid sequence comparisons revealed three amino acid differences between SaNramp6h and SaNramp6n. We investigated the Cd transport activity of the Nramp6 allele, and determined which residues are essential for the transport activity. We conducted structure-function analyses of SaNramp6 based on site-directed mutagenesis and functional assays of the mutants in yeast and Arabidopsis. The three residues that differed between SaNramp6h and SaNramp6n were mutated. Only the L157P mutation of SaNramp6h impaired Cd transport. The other mutations, S218N and T504A, did not affect the transport activity of SaNramp6h, indicating that these residues are not essential for metal selectivity. Transgenic plants overexpressing SaNramp6hL157P showed altered metal accumulation in shoots and roots. Our results suggest that the conserved site L157 is essential for the high metal transport activity of SaNramp6h. This information may be useful for limiting or increasing Cd transport by other plant natural resistance associated macrophage protein (NRAMP) proteins.

Transactivation of the human retinoid X receptor by organotins: use of site-directed mutagenesis to identify critical amino acid residues for organotin-induced transactivation

Metallomics ◽  
2015 ◽  
Vol 7 (7) ◽  
pp. 1180-1188 ◽  
Author(s):  
Youhei Hiromori ◽  
Akira Aoki ◽  
Jun-ichi Nishikawa ◽  
Hisamitsu Nagase ◽  
Tsuyoshi Nakanishi
Keyword(s):  
Amino Acid ◽  
Retinoid X Receptor ◽  
Site Directed Mutagenesis ◽  
Directed Mutagenesis ◽  
Peroxisome Proliferator ◽  
Amino Acid Residues ◽  
Endocrine Activity ◽  
Peroxisome Proliferator Activated Receptor ◽  
Critical Amino Acid ◽  
Ability To Act

Organotins, such as tributyltin (TBT) and triphenyltin (TPT), may disrupt endocrine activity in mammals arising from their ability to act as ligands for the retinoid X receptor (RXR) and the peroxisome proliferator-activated receptor γ (PPARγ).

Role of the Peroxisome Proliferator Activated Receptors in Hypertension

2021 ◽  
Vol 128 (7) ◽  
pp. 1021-1039 ◽  
Author(s):  
Shi Fang ◽  
M. Christine Livergood ◽  
Pablo Nakagawa ◽  
Jing Wu ◽  
Curt D. Sigmund
Keyword(s):  
Blood Pressure ◽  
Nuclear Receptors ◽  
Molecular Mechanisms ◽  
Large Family ◽  
Future Research ◽  
Peroxisome Proliferator ◽  
Transcriptional Responses ◽  
Peroxisome Proliferator Activated Receptor ◽  
Arterial Blood

Nuclear receptors represent a large family of ligand-activated transcription factors which sense the physiological environment and make long-term adaptations by mediating changes in gene expression. In this review, we will first discuss the fundamental mechanisms by which nuclear receptors mediate their transcriptional responses. We will focus on the PPAR (peroxisome proliferator-activated receptor) family of adopted orphan receptors paying special attention to PPARγ, the isoform with the most compelling evidence as an important regulator of arterial blood pressure. We will review genetic data showing that rare mutations in PPARγ cause severe hypertension and clinical trial data which show that PPARγ activators have beneficial effects on blood pressure. We will detail the tissue- and cell-specific molecular mechanisms by which PPARs in the brain, kidney, vasculature, and immune system modulate blood pressure and related phenotypes, such as endothelial function. Finally, we will discuss the role of placental PPARs in preeclampsia, a life threatening form of hypertension during pregnancy. We will close with a viewpoint on future research directions and implications for developing novel therapies.

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