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)

The neuronal growth-associated protein GAP-43 is expressed maximally during development and regeneration, and is enriched at the cytosolic surface of the growth cone membrane. GAP-43 can activate the GTP-binding protein G(o) which is also a major component of the growth cone membrane. These findings have led to the hypothesis that GAP-43 might modulate neurite outgrowth by altering G-protein activity. Here we define the sequence requirements for GAP-43 amino terminal peptide stimulation of G(o), and test these peptides as potential modulators of neurite outgrowth. The first 10 amino acids of GAP-43, Met-Leu-Cys-Cys-Met-Arg-Arg-Thr-Lys-Gln, stimulate G(o). Substitutions at particular residues reveal that cys3, cys4, arg6, and lys9 are critical, but arg7 is not. Both the GAP-43(1-10) peptide and the G-protein-activating peptide mastoparan induce growth cone collapse and inhibit neurite extension from embryonic chick dorsal root ganglion and retinal neurons. This is likely to be mediated by G-proteins: pertussis toxin blocks the inhibition, and mutant peptides that do not activate G(o) do not alter outgrowth. In contrast to the case with embryonic chick dorsal root ganglion cells, neurite outgrowth from N1E-115 neuroblastoma cells is stimulated by GAP-43(1-10). This is probably also a G-protein-mediated event because it is blocked by pertussis toxin, because the sequence requirements match those for G(o) stimulation, and because mastoparan stimulates outgrowth from these cells. The longer GAP-43(1-25) peptide does not alter neurite outgrowth unless the cells are permeabilized, suggesting an intracellular site of action. These data identify a novel set of compounds that modulate neurite outgrowth, and also support the notion that GAP-43 can alter neurite extension by modulating pertussis toxin-sensitive G-protein activity in the growth cone.
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PMID:GAP-43 amino terminal peptides modulate growth cone morphology and neurite outgrowth. 808 50

We have previously shown that the hepoxilins are capable of increasing the intracellular free concentration of calcium ([Ca2+]i) in human neutrophils through a pertussis toxin-sensitive, extracellular calcium-independent pathway involving the mobilization of calcium from internal stores. A subsequent hepoxilin-induced and extracellular calcium-dependent influx of calcium is observed. In an effort to investigate further the role of these compounds in the human neutrophil, we investigated their potential effects on the action of known agonists such as formyl-methionine-leucine-phenylalanine (fMLP), platelet-activating factor (PAF) and leukotriene B4 (LTB4) on the mobilization of calcium. Hepoxilis dose-dependently inhibited the increases in [Ca2+]i induced by fMLP, PAF and LTB4. The hepoxilin concentration required for inhibition was around 100 ng/ml (3 x 10(-7) M). This concentration of hepoxilin did not cause any measurable change in [Ca2+]i. The extent of inhibition of the agonist-evoked rise in [Ca2+]i by hepoxilins was proportional to the increase in the calcium response evoked by hepoxilin beyond its threshold concentration. Additional experiments were carried out to investigate the mechanism for the hepoxilin effect. Using calcium-free medium and in the presence of sufficient amounts of thapsigargin (200 ng/ml) to maximally block the calcium pump (thereby achieving a constant rate of calcium leakage from stores), hepoxilin A3 increased further this rate of calcium leakage, indicating that hepoxilin acts by rapidly draining calcium from stores. Its potential (additional) thapsigargin-like action in blocking the pump, however, cannot be ruled out by these experiments. These observations suggest that the hepoxilins may serve an important negative regulatory function in the agonist-induced mobilization of calcium in these cells by depleting calcium stores.
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PMID:Hepoxilin A3 inhibits the rise in free intracellular calcium evoked by formyl-methionyl-leucyl-phenylalanine, platelet-activating factor and leukotriene B4. 824 Feb 36

1. The electrophysiological action of the mu-opioid receptor-preferring agonist D-Ala2, MePhe4, Met(O)5-ol-enkephalin (FK 33-824) on synaptic transmission has been studied in area CA3 of organotypic rat hippocampal slice cultures. 2. FK 33-824 (1 microM) had no effect on the amplitude of pharmacologically isolated N-methyl-D-aspartate (NMDA) or non-NMDA receptor-mediated EPSPs. 3. FK 33-824 (10 nM to 10 microM) reduced the amplitude of monosynaptic inhibitory postsynaptic potentials (IPSPs) that were elicited in pyramidal cells with local stimulation after pharmacological blockade of excitatory amino acid receptors. This effect was reversible, dose-dependent, and sensitive to naloxone and the mu-receptor antagonist Cys2,Tyr3,Orn5,Pen7-amide (CTOP). FK 33-824 at 1 microM caused a mean reduction in the amplitude of the monosynaptic IPSP of 70%. 4. Neither delta- nor kappa-receptor-preferring agonists had any effect on excitatory or inhibitory synaptic potentials. 5. The disinhibitory action of FK 33-824 was blocked by incubating the cultures with pertussis toxin (500 ng/ml for 48 h) or by stimulation of protein kinase C with phorbol 12,13-dibutyrate (PDBu, 0.5 microM). 6. The depression of monosynaptic IPSPs by FK 33-824 was unaffected by extracellular application of the K+ channel blockers Ba2+ or Cs+ (1 mM each). 7. FK 33-824 produced a decrease in the frequency of miniature, action potential-independent, spontaneous inhibitory synaptic currents (mIPSCs) recorded with whole-cell voltage-clamp techniques, but did not change their mean amplitude. Application of the Ca2+ channel blocker Cd2+ (100 microM) or of nominally Ca(2+)-free solutions did not alter either the frequency and amplitude of mIPSCs or the reduction of mIPSC frequency induced by FK 33-824. 8. The effect of FK 33-824 on spontaneous mIPSCs was prevented by naloxone, and by incubation of cultures with pertussis toxin. 9. These results indicate that mu-opioid receptors decrease GABA release presynaptically by a G protein-mediated inhibition of the vesicular GABA release process, and not by changes in axon terminal K+ or Ca2+ conductances that are sensitive to extracellular Ba2+, Cs+ or Cd2+.
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PMID:Mechanism of mu-opioid receptor-mediated presynaptic inhibition in the rat hippocampus in vitro. 830 42

N-Formyl-Met-Leu-Phe (FMLP), at concentrations as low as 5 nM, caused an increase in intracellular uridine pools in dimethyl sulphoxide (Me2SO)-differentiated HL-60 cells. Intracellular uridine pools were elevated rapidly and reached a maximum within 10 min of exposure to 10 microM FMLP, followed by a gradual decline. This enhancement by FMLP was a consequence of a 3-fold increase in the Vmax of pertussis-toxin-sensitive Na(+)-dependent uridine transport system, with no change in the apparent Km. Km values of 2.67 +/- 0.45 and 3.85 +/- 0.52 microM and Vmax. values of 0.046 +/- 0.017 and 0.125 +/- 0.020 microM/s were obtained for untreated and FMLP-treated Me2SO-differentiated cells respectively. The effect of FMLP on the Na(+)-dependent transport of uridine in Me2SO-differentiated HL-60 cells was specific, as the facilitated transport of uridine was unaffected. Furthermore, this phenomenon was not observed in undifferentiated, phorbol 12-myristate 13-acetate (PMA)-differentiated or pertussis-toxin-treated Me2SO-differentiated HL-60 cells. Removal of extracellular Ca2+ with EGTA abolished the FMLP enhancement of uridine transport in a reversible manner, suggesting the involvement of Ca2+. However, the Ca2+ ionophore A23187 only partially mimicked the effect of FMLP. Similarly, with PMA the transport was sub-optimally enhanced, but a full activation was observed in cells treated with both A23187 and PMA. These findings suggest that activation of the Na(+)-dependent uridine transporter by FMLP in Me2SO-differentiated HL-60 cells involves a pertussis-toxin-sensitive G-protein with a bifurcating signal-transduction pathway.
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PMID:Enhancement of pertussis-toxin-sensitive Na(+)-dependent uridine transporter activity in HL-60 granulocytes by N-formylmethionyl-leucyl-phenylalanine. 837 25

We examined how 5-hydroxyicosatetraenoate (5-HETE) activates human neutrophils (PMN). 5-HETE stimulates PMN to mobilize Ca2+ but has little effect on degranulation or superoxide anion production. It nonetheless stereospecifically induced these responses in cells primed with tumor necrosis factor-alpha and likewise induced PMN plasma membranes to bind 35S-labeled guanosine 5'-O-(thiotriphosphate) (GTP gamma S) and phosphohydrolyze [gamma-32P]GTP. Pertussis toxin blocked GTP gamma S binding responses. Scatchard analyses of GTP gamma S binding data indicated that 5-HETE raised the Ka of high affinity GTP gamma S binding sites without altering these sites' numbers or the parameters of low affinity GTP gamma S binding. Since N-formyl-Met-Leu-Phe, platelet-activating factor, and leukotriene (LT) B4 have these same bioactions, receptors for the latter agents might mediate responses to 5-HETE. However, 5-HETE desensitized degranulation responses to itself but not to the receptor agonists, the receptor agonists desensitized to themselves but not 5-HETE, and a LTB4 antagonist inhibited LTB4 but not 5-HETE in all assays. Finally, PMN and their membranes took up [3H] 5-HETE at 4 or 37 degrees C but, at both temperatures, also acylated the radiolabel into glycerolipids. Acylation nullified assessment of 5-HETE binding and questions reports that measure the cell binding, but not metabolism, of various HETEs. Our studies thus indicate 5-HETE acts by a down-regulatable, G protein-linked mechanism and represent the best available evidence that 5-HETE does not operate through, for example, LTB4 receptors.
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PMID:5-hydroxyicosatetraenoate stimulates neutrophils by a stereospecific, G protein-linked mechanism. 839 58

Formylated Met-Leu-Phe (fMLP), platelet-activating factor (PAF), ATP, and various nonhydrolyzable guanine nucleotides stimulated accumulation of phosphatidylinositol 3,4,5-trisphosphate (PtdIns(3,4,5)P3) in intact human neutrophils. A protocol was devised to selectively inhibit the capacity of the nucleotide-sensitive receptors to elicit accumulation of PtdIns (3,4,5)P3. This enabled study of the regulation of phosphoinositide 3OH-kinase (PI3K) activities in permeabilized neutrophils free from interference due to activation of cell-surface nucleotide receptors. FMLP, PAF, and nonhydrolyzable GTP analogues stimulated an increase in the concentration, and rate of synthesis, of PtdIns(3,4,5)P3 in permeabilized neutrophils by increasing the rate of a PtdIns(4,5)P2-directed PI3K-catalyzed reaction. A number of characteristics of these responses, including their relative sensitivities to inhibition by pertussis toxin and guanosine 5'-beta-(thio)diphosphate, suggested that fMLP and PAF increased this PI3K activity via the actions of heterotrimeric G-proteins. Basal and guanosine 5'-gamma-(thio)triphosphate/fMLP-stimulated increases in PI3K activity were resistant to changes in free calcium concentrations, staurosporine, acute treatment with phorbol esters, and evidently to permeabilization. This, in conjunction with other work, indicates that the PAF and fMLP-induced increase in PtdIns(4,5)P2-directed PI3K activity is not being produced via activation of a currently defined G-protein regulated effector enzyme, or a protein tyrosine kinase coordinated mechanism of a type already known to regulate PI3K activities.
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PMID:Synthesis of phosphatidylinositol 3,4,5-trisphosphate in permeabilized neutrophils regulated by receptors and G-proteins. 839 32

It has been reported that a discrete peptide fragment of beta-amyloid protein, beta A(25-35), and neuropeptide substance P (SP) possessed sequence homology and could bind to the serine protease inhibitor (serpin) enzyme complex (SEC) receptor. Thus, it has been thought that these peptides and SEC receptor ligand might have similar biological activities. In the present study, we found that C-terminal amidated beta A(25-35)-NH2, SP, and the SEC receptor ligand, Phe-Val-Phe-Leu-Met(FVFLM), could induce an increase in the intracellular free Ca2+ concentration ([Ca2+]i) in neutrophil-like human leukemic (HL-60) cells. Pretreatment with pertussis toxin (PTX) potently inhibited the increase in [Ca2+]i stimulated by these peptides, suggesting that these responses might be mediated by PTX-sensitive G-proteins. Furthermore, we examined the effect on these responses of t-butyloxycarbonyl-methionyl-leucyl-phenylalanine (BocMLF), which is a competitive antagonist of chemotactic peptide N-formyl-methionyl-leucyl-phenylalanine (fMLF) at its receptor. BocMLF scarcely inhibited the [Ca2+]i increase stimulated by beta A(25-35)-NH2. However, the increase in FVFLM-induced [Ca2+]i was potently inhibited by BocMLF. The results suggest that the [Ca2+]i activation of beta A(25-35)-NH2 may have a different mechanism from that of FVFLM in neutrophil-like HL-60 cells, which is not mediated by the SEC-receptor.
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PMID:beta-Amyloid peptide, substance P, and SEC receptor ligand activate cytoplasmic Ca2+ in neutrophil-like HL-60 cells: effect of chemotactic peptide antagonist BocMLF. 853 82

The effect of somatostatin on Bombesin-induced contraction of isolated rabbit colonic smooth muscle cells was examined. Preincubation of muscle cells with somatostatin 10(-6) M inhibited bombesin-induced contraction. To characterize somatostatin receptors, muscle cells (10(5) cells/tube) were incubated at 24 degrees C with 125I-Tyr0-SS-28. Binding reached a plateau at 60 sec and was reversible by addition of excess synthetic SS-28. Scatchard analysis revealed high and low affinity bindings sites (Ka = 0.48 +/- 0.01 and 40 +/- 13 (nM +/- S.E.), 1830 +/- 433 and 65820 +/- 13183 receptors/cell +/- S.E.). Inhibition of 125I-Tyr0-SS-28 binding was possible with biologically active analogs of somatostatin, indicating the specificity of the receptors to somatostatin. Binding of 125I-Tyr0-SS-28 was inhibited by GTP gamma s, a nonhydrolysable analog of guanosine 5'-triphosphate, whereas adenosine 5'-triphosphate at a high concentration (100 microM) slightly inhibited the binding. Further, pretreatment of muscle cells with pertussis toxin at 37 degrees C abolished binding of 125I-Tyr0-SS-28, although pretreatment of cells with cholera toxin had no effect. Inasmuch as Gi protein is postulated as a signal protein, muscle cells were labeled with 3H-methionine, before stimulation with Bombesin (10(-6) M), in the presence and absence of somatostatin (10(-6) M). The cells were then lysed and Gi was precipitated by a Gi specific antibody. Gi synthesis was stimulated by bombesin at 60 sec and somatostatin inhibited it (6114 +/- 986 vs. 2998 +/- 841 cpm +/- S.E., P < .05). These data suggest that colonic smooth muscle cells contain specific receptor for somatostatin-28 and that somatostatin reverses bombesin-induced contraction regulated by Gi-type G protein.
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PMID:Somatostatin inhibits bombesin-stimulated Gi-protein via its own receptor in rabbit colonic smooth muscle cells. 863 41

The cytoskeletal localization of inhibitory guanine-nucleotide-binding (Gi) proteins and the coupling of these proteins to formyl peptide receptors were studied in myeloid differentiated human leukemia (HL-60) cells. Treatment of HL-60 cells with cytochalasin B or botulinum C2 toxin, which leads to the disruption of microfilaments, increased the binding of the stable GTP analogue guanosine 5'[gamma-thio]triphosphate (GTPS[S]) to permeabilized cells by about 30%. In contrast, the microtubule-disrupting agents colchicine and vinblastine, and cytochalasin B treatment of isolated HL-60 membranes did not affect GTP[S] binding. The stimulatory effect of cytochalasin B treatment was concentration and time dependent, with maximal increases observed at 5 micrograms/ml cytochalasin B and an incubation time of 10 min, and was counteracted by the F-actin-stabilizing toxin phalloidin. Cytochalasin B treatment increased the amount of G proteins activated by chemoattractant receptors by about 25%. Furthermore, the number of Gi-protein-coupled receptors for the chemoattractant, N-formyl-Met-Leu-Phe, was increased by about 25% upon cytochalasin B treatment. Based on these functional data, which suggest an association of G proteins with actin filaments, the Triton X-100 (1%)-insoluble cytoskeleton was analyzed for the presence of G proteins. Gia subunits were detected in the cytoskeleton preparations, both by specific antisera and by pertussis-toxin -catalyzed ADP-ribosylation. Cytochalasin B pretreatment depleted the cytoskeleton in Gialpha, with an approximately 20% concomitant increase in membrane Gialpha content. In conclusion, evidence is presented that part of the cellular Gia is localized at actin filaments in HL-60 cells. After filament disruption, these Gia subunits seem to be translocated to the plasma membrance, where they can productively interact with chemoattractant receptors.
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PMID:Translocation of microfilament-associated inhibitory guanine-nucleotide-binding proteins to the plasma membrane in myeloid differentiated human leukemia (HL-60) cells. 865 16

The chemotactic peptide f-Met-Leu-Phe (fMLP) stimulates leukocyte functions through binding and activation of a specific G-protein-coupled formyl peptide receptor (FPR). Recent studies have shown that stimulation of neutrophils with fMLP induces the activation of two members of the mitogen-activated protein kinase (MAP kinase) family, ERK1 and ERK2, through mechanisms that are not completely understood but may involve the phosphorylation of the adapter protein SHC by the Src-related kinase Lyn. In this study, transfected fibroblasts expressing the rabbit FPR were used to investigate further the role of Lyn and SHC phosphorylation in fMLP-stimulated MAP kinase activation. Stimulation of transfected cells with fMLP resulted in the time- and dose-dependent increase in tyrosine phosphorylation and activation of ERK1 and ERK2 and the activation of MEK, the MAP kinase/ERK kinase. The activation of both ERKs and MEK was inhibited by preincubation of the cells with pertussis toxin, indicating that activation was dependent upon a Gi/Go-like protein that couples to the receptor. Our data also show that, unlike neutrophils, FPR-transfected fibroblasts do not express the Src-related kinase Lyn. In the absence of Lyn, fMLP stimulation did not result in an increased tyrosine phosphorylation of the adapter protein SHC, whereas it was still able to induce MAP kinase activation. These data suggest that Lyn and SHC are not the only upstream signals for activation of the MAP kinase/ERK pathway by fMLP and demonstrate the potential application of the FPR-transfected cells for the delineation of additional signaling mechanisms stimulated by fMLP.
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PMID:Activation of the mitogen-activated protein kinase pathway by fMet-leu-Phe in the absence of Lyn and tyrosine phosphorylation of SHC in transfected cells. 866 60


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