Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0043167 (pertussis)
 19,595 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Homologues of the transcriptional regulator FNR from Escherichia coli have been identified in a variety of taxonomically diverse bacterial species. Despite being structurally very similar, members of the FNR family have disparate regulatory roles. Those from Shewanella putrefaciens, Pseudomonas aeruginosa, Pseudomonas stutzeri and Rhodopseudomonas palustris are functionally similar to FNR in that they regulate anaerobic respiration or carbon metabolism. Four rhizobial proteins (from Rhizobium meliloti, R. leguminosarum, B. japonicum and Azorhizobium caulinodans) are involved in the regulation of nitrogen fixation; a fifth (from Rhizobium strain IC3342) has unknown function. Two proteins from mammalian pathogens (Actinobacillus pleuropneumoniae and Bordetella pertussis) may be involved in the regulation of toxin expression. The FNR protein of Vibrio fischeri regulates bioluminescence, and the function of the one known FNR homologue from a Gram-positive organism (Lactobacillus casei) remains to be elucidated. Some members of this family, like FNR itself, appear to function as sensors of oxygen availability, whereas others do not. The ability to sense and respond to oxygen limitation may be correlated with the presence of cysteine residues which, in the case of FNR, are thought to be involved in oxygen or redox sensing. The mechanism of DNA sequence recognition is probably conserved, or very similar, throughout this family. In a number of other Gram-negative species, there is good indirect evidence for the existence of FNR analogues; these include Alcaligenes eutrophus, A. denitrificans, A. faecalis, Paracoccus denitrificans and a number of Pseudomonas species.
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PMID:The FNR family of transcriptional regulators. 774 34

A cDNA clone, RGA1, was isolated by using a GPA1 cDNA clone of Arabidopsis thaliana G protein alpha subunit as a probe from a rice (Oryza sativa L. IR-36) seedling cDNA library from roots and leaves. Sequence analysis of genomic clone reveals that the RGA1 gene has 14 exons and 13 introns, and encodes a polypeptide of 380 amino acid residues with a calculated molecular weight of 44.5 kDa. The encoded protein exhibits a considerable degree of amino acid sequence similarity to all the other known G protein alpha subunits. A putative TATA sequence (ATATGA), a potential CAAT box sequence (AGCAATAC), and a cis-acting element, CCACGTGG (ABRE), known to be involved in ABA induction are found in the promoter region. The RGA1 protein contains all the consensus regions of G protein alpha subunits except the cysteine residue near the C-terminus for ADP-ribosylation by pertussis toxin. The RGA1 polypeptide expressed in Escherichia coli was, however, ADP-ribosylated by 10 microM [adenylate-32P] NAD and activated cholera toxin. Southern analysis indicates that there are no other genes similar to the RGA1 gene in the rice genome. Northern analysis reveals that the RGA1 mRNA is 1.85 kb long and expressed in vegetative tissues, including leaves and roots, and that its expression is regulated by light.
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PMID:Molecular cloning and characterization of RGA1 encoding a G protein alpha subunit from rice (Oryza sativa L. IR-36). 776 94

The hypothesis that carboxylmethylation of gamma subunits plays a role in G protein activation was tested by examining the ability of N-acetyl-S-farnesyl-L-cysteine (AFC) and its methyl ester (AFC-ME) to inhibit G protein-mediated signalling in intact HL-60 granulocytes and isolated HL-60 plasma membranes. Incubation of HL-60 granulocytes with AFC or AFC-ME inhibited superoxide release stimulated by fMet-Leu-Phe, but not by opsonized bacteria. AFC-ME, but not AFC, inhibited NaF- and PMA-stimulated superoxide release. Addition of AFC to HL-60 membranes inhibited fMet-Leu-Phe-, leukotriene B4- (LTB4) and C5a-stimulated GTP gamma S binding and GTP hydrolysis more potently than it inhibited basal guanine nucleotide exchange. AFC-ME inhibited basal- and ligand-stimulated G protein activation with equal potency, but less potently than AFC. AFC also inhibited mastoparan-stimulated GTP gamma S binding. Binding of fMet-Leu-Phe and LTB4 to HL-60 membranes was completely inhibited by AFC, while AFC-ME inhibited ligand binding by less than 50%. Neither AFC nor AFC-ME inhibited pertussis toxin or cholera toxin-catalysed ADP-ribosylation of alpha i. It was concluded that AFC interrupts signal propagation in G protein-dependent pathways by multiple mechanisms, including inhibition of ligand-receptor interactions, of receptor-G protein coupling and of guanine nucleotide binding to G proteins. Carboxylmethylation alters the specificity of AFC interruption of signal propagation in intact cells and isolated membranes.
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PMID:Effect of prenylcysteine analogues on chemoattractant receptor-mediated G protein activation. 781 93

Nitric oxide (NO), a free-radical gas produced endogenously by some neurons, functions as a diffusible intercellular messenger and appears to play a role in activity-dependent modification of synaptic efficacy in the mammalian CNS. The molecular targets and mechanisms of action of NO in neurons remain largely uncharacterized. Employing in vitro brain slices and isolated synaptosomes, we show here that exposure to exogenous or endogenously generated NO results in the modification of cysteine residues within neuronal proteins, as revealed by reduced binding of agents which react with cysteine sulfhydryls. In particular, exposure of synaptosomes to NO inhibits subsequent thiol-linked ADP-ribosylation of the heterotrimeric G-protein, G(o), by pertussis toxin. Our results demonstrate directly that NO may exert its neuronal effects through modification of protein cysteine thiols, and identify G(o) as a potential synaptic target of NO.
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PMID:Modification of cysteine residues within G(o) and other neuronal proteins by exposure to nitric oxide. 787 Feb 85

A rat glycohydrolase which catalyzes the hydrolysis of ADP-ribosylarginine was expressed in Escherichia coli and purified to homogeneity for characterization of its enzymatic properties. The purified glycohydrolase catalyzed the hydrolysis of N-glycoside linked ADP-ribosylarginine on the alpha-subunits of stimulatory GTP-binding proteins (Gs) and cholera toxin A1-subunit that had been modified by cholera toxin and NAD. Nonmuscle actin of which an arginine residue was ADP-ribosylated by botulinum C2 toxin also served as a substrate of the glycohydrolase. On the other hand, the glycohydrolase did not hydrolyze ADP-ribosylated cysteine on the alpha-subunits of pertussis toxin-substrate GTP-binding proteins, ADP-ribosylated diphthamide on elongation factor 2, or ADP-ribosylated asparagine on rho GTP-binding proteins. The rate of the reaction catalyzed by the glycohydrolase was affected by nucleotide-binding form of the ADP-ribosylated substrate proteins; the GDP-bound form of the modified Gs-alpha was more rapidly hydrolyzed than the guanosine 5'-(3-O-thio)triphosphate-bound form. Interestingly, the glycohydrolase activity was markedly inhibited by mM order concentration of ATP in addition to ADP-ribose, the product of the enzyme reaction, though ADP had no inhibitory effect on the activity. Moreover, alpha NAD, but not beta NAD, inhibited the enzyme activity, suggesting that the glycohydrolase reaction was stereospecific for the alpha-anomer.
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PMID:ADP-ribosylarginine glycohydrolase catalyzing the release of ADP-ribose from the cholera toxin-modified alpha-subunits of GTP-binding proteins. 789 43

Mono-ADP-ribosylation is a protein modification that occurs at a number of different amino acids, dictated by the specificity of the individual ADP-ribosyltransferases. A specific cysteine in several guanine nucleotide-binding regulatory proteins is ADP-ribosylated by the bacterial protein pertussis toxin. Recent purification of an ADP-ribosylcysteine hydrolase and NAD:cysteine ADP-ribosyltransferase, and detection of ADP-ribose-cysteine linkages in tissue samples has raised hope that an endogenous regulatory cysteine-specific ADP-ribosylation pathway exists. A current goal is the identification of such a pathway for ADP-ribosylation of cysteine within animal cells. Interpretation of the data in this field has been complicated by recent reports that revealed several unforeseen chemical reactions of NAD and its metabolites with free cysteine and cysteine in proteins. This mini-review covers the latest understanding of the ADP-ribosylation reactions associated with cysteine, and provides a set of criteria for future research to establish positively the existence of an endogenous cysteine-specific mono-ADP-ribosyltransferase.
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PMID:Enzymatic and nonenzymatic ADP-ribosylation of cysteine. 789 67

The S1 subunit of pertussis toxin is an ADP-ribosyl-transferase capable of transferring the ADP-ribose moiety of NAD+ to nucleotide-binding signal-transducing proteins of the Gi/G(o) family. In the absence of G proteins, the enzyme also catalyzes the hydrolysis of NAD+. Glu-129 was previously shown to be critical for both enzymatic activities. In this study, site-directed mutagenesis was used to make the conservative substitution of aspartate for Glu-129. The recombinant wild type and mutant proteins were purified to near homogeneity and used for enzymatic analyses. Kinetic experiments showed that the kcat of the mutant protein was about 200 times less than that of the wild type enzyme, whereas the Km for NAD+ of the two proteins were very similar, suggesting that Glu-129 is a catalytic residue for the NAD-glycohydrolase reaction of S1. This hypothesis was confirmed by a less than 2-fold change in Kd as measured by fluorescence quenching studies, indicating that the binding of NAD+ is not affected in the mutant protein in any important way. In another experiment, the replacement of Glu-129 by cysteine resulted in a disulfide bridge between Cys-129 and Cys-41 in rS1d-E129C, suggesting that the folding of the polypeptide chain is such that the catalytic Glu-129 residue is close to the amino-terminal NAD-binding site of S1. These findings imply that Glu-129 plays a key role in catalysis of the NAD-glycohydrolase reaction, possibly by electrostatically stabilizing a cationic transition state intermediate, or by serving as a general base to deprotonate the ADP-ribosyl acceptor substrates.
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PMID:Evidence for a catalytic role of glutamic acid 129 in the NAD-glycohydrolase activity of the pertussis toxin S1 subunit. 790 Dec 13

Site-directed mutations of the cDNA for Gi1 alpha, Gi21 alpha, and Gi3 alpha were constructed which changed the cysteine residue at the C terminus to a glycine residue (Gi alpha PT). This mutation of the Gi alpha would not permit the subsequent covalent modification by pertussis toxin, which requires the cysteine moiety. The cDNA for each of the mutant Gi alpha subunits was transfected into GH4C1 cells with either of the alternative splice forms of the D2 dopamine receptor and clonal lines were generated. After treatment with pertussis toxin to remove the contribution from endogenous Gi proteins, the receptor-mediated inhibition of adenylyl cyclase was examined. The D2 dopamine receptor, short form (D2s) signaled through the Gi2 alpha PT mutant in these cells with an affinity for agonist which was comparable to that observed in cells transfected with the cDNA for D2s alone or the signaling observed in the absence of pertussis toxin. The long form of the D2 dopamine receptor (D2l) signaled through the Gi3 alpha PT mutant to inhibit forskolin-stimulated adenylyl cyclase, with an affinity for agonist comparable to that observed in cells transfected with the cDNA for D2l alone. The receptor for somatostatin (somatotropin release inhibiting factor) was used as an endogenous control receptor in these cell lines. The somatotropin release inhibiting factor was able to signal through both Gi1 alpha PT and Gi3 alpha PT to inhibit forskolin-stimulated adenylyl cyclase. These results indicated that receptors use distinct Gi proteins to signal to a common effector.
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PMID:The D2 dopamine receptor isoforms signal through distinct Gi alpha proteins to inhibit adenylyl cyclase. A study with site-directed mutant Gi alpha proteins. 791 15

Using recombinantly expressed proteins and synthetic peptides, we examined the structural/functional features of the platelet chemokines, neutrophil-activating peptide-2 (NAP-2) and platelet factor 4 (PF4); that were important in their activation of neutrophils. Previous studies with the chemokine interleukin-8 (IL-8) had shown that the N-terminal region preceding the first cysteine residue was critical in defining neutrophil-activating properties. We examined whether NAP-2 and PF4 had similar structural requirements. In the Ale-glu-leu-arg (AELR) N-terminus of NAP-2, substitution of E or R abolished Ca2+ mobilization and elastase secretion. Unlike the parent molecule PF4, AELR/PF4, the hybrid formed by replacing the N-terminal sequence of PF4 before the first cysteine residue with the homologous sequence of NAP-2, stimulated Ca2+ mobilization and elastase secretion. Furthermore, the effect of amino acid substitutions in the ELR motif differed from those seen with NAP-2 in that conserved substitutions of E or R in NAP-2 abolished activity, but only reduced neutrophil activation in the hybrid. These studies show that just as with IL-8, the N-termini of NAP-2 and PF4 are critical for high-level neutrophil-activating function. Desensitization studies provided information on receptor binding. NAP-2, which binds almost exclusively to the type 2 IL-8 receptor (IL-8R), did not desensitize neutrophils to activation by IL-8 because IL-8 could bind to and activate via both type 1 and 2 IL-8R. AELR/PF4 appears to bind to both types of receptors because it desensitized neutrophils to NAP-2 activation; but was not desensitized by NAP-2, and because it desensitized to and was desensitized by IL-8. Thus, although NAP-2 and AELR/PF4 share approximately 60% amino acid homology, they have different receptor affinities. Studies were performed to define the role of the C-termini of these platelet chemokines in receptor binding. Heparin and a monoclonal antibody specific for the heparin-binding domain of PF4 both inhibited Ca2+ mobilization and elastase release, further suggesting that the C-terminus of these chemokines is important in receptor binding. Synthetic NAP-2(51-70) failed to mobilize Ca2+, whereas PF4(47-70) and PF4(58-70) induced Ca2+ mobilization and secretion of elastase at high concentrations. Pertussis toxin inhibited neutrophil activation by 40% to 50%, establishing a role for G-protein-coupled receptors such as the IL-8Rs in activation by the PF4 C-terminal peptides.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Structural requirements of platelet chemokines for neutrophil activation. 791 50

Plasmids containing cDNAs encoding either the wild-type guanine-nucleotide-binding protein G(o)1 alpha or the palmitoylation-negative cysteine-3-to-serine (C3S) mutant of G(o)1 alpha were transfected into Rat 1 cells, and clones stably expressing immunoreactivity corresponding to these polypeptides were isolated. Clones C5B (expressing wild-type G(o)1 alpha) and D3 (expressing the mutant form) were selected for detailed study. Immunoprecipitation of whole cell lysates of each clone labelled with either [3H]palmitate or [3H]myristate demonstrated incorporation of [3H]myristate into both wild-type and the C3S mutant of G(o)1 alpha, but that incorporation of hydroxylamine-sensitive [3H]palmitate was restricted to the wild type. When membrane and cytoplasmic fractions were prepared from cells of either the C5B or D3 clones, although immunodetection of wild-type G(o)1 alpha was observed only in the membrane fraction, the C3S mutant was present in both membrane and cytoplasmic fractions. Furthermore, a significant proportion of the C3S G(o)1 alpha immunoreactivity was also detected in the cytoplasmic fraction if immunoprecipitation of recently synthesized G(o)1 alpha was performed from fractions derived from cells pulse-labelled with [35S]Trans label. Pretreatment of cells of both clones C5B and D3 with pertussis toxin led to complete ADP-ribosylation of the cellular population of G(o)1 alpha in both cell types, irrespective of whether the polypeptide was subsequently found in the membrane or cytoplasmic fraction following cellular disruption. By contrast, separation of membrane and cytoplasmic fractions before pertussis-toxin-catalysed [32P]ADP-ribosylation allowed modification only of the membrane-associated G(o)1 alpha (whether wild-type or the C3S mutant). This labelling was decreased substantially by incubation of the membranes with guanosine 5'-[beta gamma-imido]triphosphate. No cytoplasmic G-protein beta subunit was detected immunologically, and the non-membrane-associated C3S G(o)1 alpha from D3 cells migrated as an apparently monomeric 40 kDa protein on a Superose 12 gel-filtration column. Membrane-associated wild-type and C3S G(o)1 alpha appeared to interact with guanine nucleotides with similar affinity, as no alteration in the dose-response curves for guanine-nucleotide-induced maintenance of a stable 37 kDa tryptic fragment was noted for the two forms of G(o)1 alpha. Chemical depalmitoylation of membranes of clone C5B with neutral 1 M hydroxylamine caused a release of some 25-30% of each of G(o)1 alpha, Gi2 alpha and Gq alpha/G11 alpha from the membranes. Equivalent treatment of D3 cells caused an equivalent release of Gi2 alpha and Gq alpha/G11 alpha, but was unable to cause any appreciable release of the CS3 form of G(o)1 alpha, which was membrane-bound.
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PMID:The palmitoylation status of the G-protein G(o)1 alpha regulates its activity of interaction with the plasma membrane. 794 20


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