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)

A 40-kDa protein, in addition to the alpha-subunits of Gs (a GTP-binding protein involved in adenylate cyclase stimulation), was [32P]ADP-ribosylated by cholera toxin (CT) in the membranes of neutrophil-like HL-60 cells, only if formyl Met-Leu-Phe (fMLP) was added to the ADP-ribosylation mixture. The 40-kDa protein proved to be the alpha-subunit of Gi serving as the substrate of pertussis toxin, islet-activating protein (IAP). No radioactivity was incorporated into this protein in membranes isolated from HL-60 cells that had been exposed to IAP. Gi-alpha purified from bovine brain and reconstituted into IAP-treated cell membranes was ADP-ribosylated by CT plus fMLP. Gi-alpha was ADP-ribosylated by IAP, but not by CT plus fMLP, in membranes from cells that had been pretreated with CT plus fMLP. When membrane Gi-alpha [32P]ADP-ribosylated by CT plus fMLP or IAP was digested with trypsin, the radiolabeled fragments arising from the two proteins were different from each other. These results suggest that CT ADP-ribosylates Gi-alpha in intact cells when coupled fMLP receptors are stimulated and that the sites modified by two toxins are not identical. CT-induced and fMLP-supported ADP-ribosylation of Gi-alpha was favored by Mg2+ and allow concentrations of GTP or its analogues but suppressed by GDP. The ADP-ribosylation did not occur at all, even in the presence of ADP-ribosylation factor that supported CT-induced modification of Gs, in phospholipid vesicles containing crude membrane extract in which Gi was functionally coupled to stimulated fMLP receptors. Thus, Gi activated via coupled receptors is the real substrate of CT-catalyzed ADP-ribosylation. This reaction may depend on additional factor(s) that are too labile to survive the process of membrane extraction.
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PMID:Chemotactic peptide receptor-supported ADP-ribosylation of a pertussis toxin substrate GTP-binding protein by cholera toxin in neutrophil-type HL-60 cells. 251 94

In neutrophils and several other phagocytes, a pertussis and cholera toxin-sensitive guanine nucleotide-binding protein (G-protein) couples the receptors for formyl methionine-containing chemotactic peptides to stimulation of phospholipase C. We used membranes of myeloid-differentiated HL 60 cells to study the role of Na+ in regulating both the interaction of the formyl peptide receptor with the chemotactic agonist, N-formyl-methionyl-leucyl-phenylalanine (FMLP), and the receptor-mediated activation of the G-protein. Monovalent cations (Na+ greater than Li+ greater than K+ greater than choline+) markedly inhibited the binding of the radiolabeled oligopeptide [3H]FMLP by specifically reducing the number of receptors in the high-affinity state. Half-maximal and maximal inhibition of peptide binding were seen at cation concentrations of approximately 20 and 200 mM, respectively. Inhibition of peptide binding by Na+ was observed in the presence and absence of divalent cations and was strictly additive to inhibition by the poorly hydrolyzable GTP analogue, guanosine-5'-O-(3-thiotriphosphate), or to ADP ribosylation of G-proteins by pertussis toxin. The inhibitory effect of Na+ on peptide binding coincided with a marked reduction of the potency of FMLP to stimulate a high-affinity GTPase. In contrast, the degree of FMLP-stimulated GTPase activity was markedly enhanced in the presence of Na+. This was largely due to the fact that Na+ reduced the agonist-independent basal GTPase activity in the same way but less so than pertussis toxin treatment. The results show that monovalent cations, Na+ in particular, regulate the interaction of the formyl peptide receptor with both the chemotactic agonist and the G-protein by acting on a single site, possibly located on the receptor itself. The observation that basal GTPase activity is markedly reduced by both Na+ and pertussis toxin treatment also suggests (a) that G-proteins interact with and are activated by receptors even in the absence of agonists and (b) that Na+ uncouples unoccupied receptors from G-protein interaction and activation.
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PMID:Na+ regulation of formyl peptide receptor-mediated signal transduction in HL 60 cells. Evidence that the cation prevents activation of the G-protein by unoccupied receptors. 251 70

The structural organization of the low molecular mass form (43 kDa) of Bordetella pertussis adenylate cyclase was dissected taking advantage of the known sequence of the bacterial cya gene (Glaser, P., Ladant, D., Sezer, O., Pichot, F., Ullmann, A., and Danchin, A. (1988) Mol. Microbiol. 2, 19-30) and its low content of Trp and Met residues. Cleavage of the 43-kDa protein and of its complementary tryptic fragments (T25 and T18 peptides) with N-chlorosuccinimide and cyanogen bromide followed by sodium dodecyl sulfate-polyacrylamide gel analysis of digestion products allowed the following conclusions: (i) the catalytically active 43-kDa form of B. pertussis adenylate cyclase is within the first 400 residues of the protein encoded by the cya gene. T25 occupies the N-terminal domain of the protein (residues 1-235/237). Isolated T25 fragment exhibits a low but measurable enzymatic activity which indicates that it harbors the catalytic site; (ii) T18 which is the main calmodulin-binding domain, occupies the C-terminal segment of protein (residues 236/238-399) and is devoid of catalytic properties; (iii) the two complementary peptides T25 and T18 reassociated only in the presence of calmodulin, leading to significant recovery of the original activity. These results demonstrate that both fragments of the 43-kDa form of adenylate cyclase are essential for a high level of enzymatic activity.
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PMID:Characterization of the calmodulin-binding and of the catalytic domains of Bordetella pertussis adenylate cyclase. 253 1

In the human premonocytic line U937, 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3) induces a functional NADPH oxidase, that is responsive to both phorbol esters and opsonized zymosan. The chemotactic peptide f-Met-Leu-Phe (fMLP) did not, however, induce superoxide generation by these cells. This was not due to the absence of receptors for fMLP. Although there was no significant binding of [3H]-fMLP to undifferentiated U937 cells, preincubation with 1,25-(OH)2D3 induced expression of specific and saturable binding sites. Moreover, fMLP induced a rapid and reversible rise in cytosolic free Ca2+ concentration ([Ca2+]i) in 1,25-(OH)2D3-treated U937 cells, but not in control or 24,25-dihydroxyvitamin D3 (24,25-(OH)2D3)-treated cells. This [Ca2+]i response was dependent on concentrations of both fMLP and 1,25-(OH)2D3 and was observed at physiologic concentrations of the hormone (approximately 25 pM). The rise in [Ca2+]i induced by fMLP in 1,25-(OH)2D3-treated U937 cells was blocked by pertussis toxin and presumably mediated by inositol (1,4,5)-trisphosphate generation. These results indicate that in U937 cells differentiated with 1,25-(OH)2D3, inositol phosphate-mediated [Ca2+]i responses to fMLP are uncoupled from NADPH oxidase activation.
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PMID:1,25-dihydroxyvitamin D3 induces responsiveness to the chemotactic peptide f-Met-Leu-Phe in the human monocytic line U937: dissociation between calcium and oxidative metabolic responses. 254 Feb 55

A 2.7-kb cya A gene fragment encoding the amino-terminal end of the calmodulin-sensitive adenylate cyclase from Bordetella pertussis has been placed under the control of the lac promoter for expression in Escherichia coli. Following induction with isopropyl beta-D-thiogalactoside, calmodulin-sensitive adenylate cyclase activity was detected in a cell extract from E. coli. The expression vector directed the synthesis of a 90-kDa polypeptide that was recognized by rabbit polyclonal antibodies raised against the catalytic subunit of B. pertussis adenylate cyclase. Inspection of the deduced amino acid sequence of the cya A gene product revealed a sequence with homology to consensus sequences for an ATP-binding domain found in many ATP-binding proteins. On the basis of the analysis of nucleotide binding proteins, a conserved lysine residue has been implicated in the binding of ATP. A putative ATP-binding domain in the B. pertussis adenylate cyclase possesses an analogous lysine residue at position 58. To test whether lysine 58 of the B. pertussis adenylate cyclase is a crucial residue for enzyme activity, it was replaced with methionine by oligonucleotide-directed mutagenesis. E. coli cells were transformed with the mutant cya A gene, and the expressed gene product was characterized. The mutant protein exhibited neither basal nor calmodulin-stimulated enzyme activity, indicating that lysine 58 plays a critical role in enzyme catalysis.
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PMID:Site-directed mutagenesis of lysine 58 in a putative ATP-binding domain of the calmodulin-sensitive adenylate cyclase from Bordetella pertussis abolishes catalytic activity. 254 36

A mu-opioid receptor-GTP binding protein (mu-opioid receptor-G-protein) complex from the 7315c cell was solubilized with CHAPS (3-[(3-cholamidopropyl)dimethylammonio]-1-propane sulfonate) and reconstituted into phospholipid vesicles. Pretreatment of the tissue with either [3H]etorphine or morphine greatly improved recovery of the receptor and maintained it in a GTP-sensitive state. GTP sensitivity was consistent with the hypothesis that a receptor-G-protein complex had been obtained. Other evidence consistent with this hypothesis was that recovery of the solubilized, prelabelled receptor was decreased by approximately 70% by pretreatment of 7315c cells with pertussis toxin. The reconstituted receptor was mu-selective: DAGO (Tyr-D-Ala-Gly-Met-Phe- NH(CH2)2OH), but not ICI 174864 or U50488-H, displaced [3H]etorphine binding with high affinity. The affinity of the reconstituted receptor for [3H]etorphine (1.25 +/- 0.20 nM) was similar to that observed for the membrane-associated receptor (0.53 +/- 0.25 nM). GTP gamma S decreased this affinity 3-fold without changing the number of binding sites. The potencies of GTP gamma S and GTP in diminishing [3H]etorphine binding were similar in the membrane and vesicle preparations, but were 10-fold lower than the potencies observed in diminishing binding to the solubilized receptor. The ability to reconstitute a functional mu-opioid receptor-G-protein complex will facilitate further study of the structure and function of the receptor and the specific identification of the associated GTP-binding protein(s).
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PMID:Reconstitution of the solubilized mu-opioid receptor coupled to a GTP-binding protein. 255 7

1. Neurons with a receptor responded to FMRFamide (Phe-Met-Arg-Phe-NH2) were identified in the ganglion of Aplysia kurodai. Ionic mechanism and channel gating system of the FMRFamide-induced responses were investigated by current clamp and voltage clamp methods. 2. The reversal potential of FMRFamide-induced response exactly coincided with the equilibrium potential for K+. This proved that the response was produced by a specific increase in membrane permeability toward K+, exclusively. 3. The FMRFamide-induced response was not affected by the inhibitors for Ca2(+)-activated K(+)-current, i.e., TEA, apamin, and EGTA. This excluded a possibility that FMRFamide-activated K(+)-channel is a Ca2(+)-activated K(+)-channel. 4. Intracellular injection of pertussis-toxin (PTX) caused no change in either resting potential or conductance, but it irreversibly blocked the FMRFamide-induced outward current within 30 min. Similarly applied cholera toxin (CTX) showed no effect on the FMRF-amide response. 5. Intracellular application of guanosine 5'-0-(2-thiodiphosphate) (GDP beta S) caused no effect on either resting potential or conductance, but it blocked the FMRFamide-induced K(+)-current within 3 min. 6. Intracellular application of guanosine 5'-0-(3-thiotriphosphate) (GTP gamma S) alone induced a slowly developing, irreversible outward current associated with an increase in membrane conductance. However, repetitive applications of FMRFamide immediately after the start of GTP gamma S application markedly facilitated the effect of GTP gamma S on the resting membrane. 7. Intracellular application of either adenylate cyclase inhibitor (3'-deoxyadenosine) or A-kinase inhibitor (H-8) did not affect the FMRFamide-induced response. 8. It was concluded that the FMRFamide-induced K(+)-current is mediated by PTX-sensitive GTP-binding protein Gi, Go or Gk. It was also suggested that the FMRFamide-induced response is produced independently of the changes in intracellular Ca2+ or cyclic AMP.
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PMID:[The gating mechanism of K(+)-channels coupled to the FMRFamide receptor in the ganglion cells of Aplysia]. 255 80

The neurotransmitters histamine, dopamine and the peptide Phe-Met-Arg-Phe-NH2 (FMRFa) cause presynaptic inhibition in the nervous system of the marine mollusk Aplysia Californica by combined down-modulation of a Ca++ conductance and up-modulation of a K+ conductance. The action of FMRFa on the S-type K+ channels of Aplysia sensory neurons is mediated by a metabolite of the 12-lipoxygenase pathway of arachidonic acid, possibly 12-HPETE. A Pertussis toxin-sensitive GTP binding protein couples FMRFa receptor to the activation of the arachidonic cascade. Once produced, 12-HPETE does not require ATP- or GTP-dependent processes to act on the K+ channels, but it may directly modulate the channel via an external membrane receptor. Based on this observation, a role for eicosanoids as possible intercellular messengers in the C.N.S. is discussed.
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PMID:Arachidonic acid metabolites as mediators of synaptic modulation. 256 69

Different aspects of lethal infection of infant mice with Bordetella pertussis were examined. Mutants deficient in vir-regulated genes were tested for the ability to cause a lethal infection in the infant mouse model. Adenylate cyclase toxin-hemolysin and pertussis toxin were required to cause a lethal infection at low doses. Mixed infection caused by challenging the mice with an equal number of pertussis toxin and adenylate cyclase toxin-hemolysin mutants at a dose at which neither alone was lethal was also unable to cause a lethal infection. Production of the filamentous hemagglutinin and the dermonecrotic toxin was not required to cause a lethal infection. Nine other mutants in vir-regulated genes whose phenotypes have yet to be determined were also tested. Only two of these mutants were impaired in the ability to cause a lethal infection. Expression of fimbriae does not appear to affect the dose required to cause a lethal infection; however, fimbrial expression was correlated with the later stages of a nonlethal, persistent infection. Growth of the bacteria in MgSO4, a condition which reversibly suppresses expression of the genes required for virulence, did not alter the ability of the bacteria to cause a lethal infection. Auxotrophic mutants deficient in leucine biosynthesis were as virulent as the parental strain; however, mutants deficient in methionine biosynthesis were less virulent. A B. parapertussis strain was much less effective in promoting a lethal infection than any of the wild-type B. pertussis strains examined. A persistent infection in the lungs was observed for weeks after challenge for mice given a sublethal dose of B. pertussis, and transmission from infected infants to the mother was never observed.
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PMID:Lethal infection by Bordetella pertussis mutants in the infant mouse model. 257 61

The rise in cytosolic free Ca2+, shape change, superoxide formation, and granule exocytosis induced in human neutrophils by N-formyl-Met-Leu-Phe (fMLP) and by a newly discovered activating peptide, neutrophil-activating factor, termed NAF, were compared. NAF was effective in the concentration range of 0.1-10 nM and was 10- to 100-fold more potent than fMLP. In qualitative terms, the single responses to either stimulus were remarkably similar: they showed virtually identical onset and initial kinetics, and were all inhibited by pretreatment of the neutrophils with Bordetella pertussis toxin. In addition, the respiratory burst elicited by either stimulus was inhibited by 17-hydroxywortmannin and staurosporine. Two conclusions are drawn from these results: 1) neutrophil activation by NAF (as by fMLP) is dependent on a GTP-binding protein and on protein kinase C; 2) a similar, or even identical, mechanism of signal transduction must be assumed on stimulation of human neutrophils with NAF, fMLP, and other chemotactic agonists. Human monocytes, lymphocytes, and platelets did not show cytosolic free Ca2+ changes when exposed to NAF, which suggests that NAF is selective for the neutrophils.
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PMID:Mechanism of neutrophil activation by NAF, a novel monocyte-derived peptide agonist. 284 Mar 18


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