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

The mechanism of action of vasoactive intestinal polypeptide on gastric acid secretion was examined in the isolated, luminally perfused mouse stomach. Vasoactive intestinal polypeptide caused a weak, transient increase in basal and histamine-stimulated acid secretion and a sustained increase in somatostatin secretion. The sustained increase in somatostatin despite return of acid to basal levels indicated that somatostatin secretion was a direct response to vasoactive intestinal polypeptide and not mediated by intraluminal acidification. The increase in somatostatin secretion was partly responsible for the weak, transient nature of the acid response since incubation with pertussis toxin, which is known to block the inhibitory effect of exogenous and endogenous somatostatin, converted the acid response to a sustained increase throughout the period of stimulation. The inhibitory influence of somatostatin was confirmed with selective vasoactive intestinal polypeptide antagonists. The antagonists inhibited vasoactive intestinal polypeptide-induced somatostatin secretion but caused a sustained increase in acid secretion. The pattern of response implied that somatostatin secretion was more sensitive than acid secretion to vasoactive intestinal polypeptide and vasoactive intestinal polypeptide antagonists and that suppression of somatostatin eliminated the main inhibitory influence on acid secretion. In addition, both vasoactive intestinal polypeptide antagonists inhibited basal somatostatin secretion, implying that input from tonically active vasoactive intestinal polypeptide neurons is responsible, at least in part, for basal somatostatin secretion.
 ...
PMID:The effect of vasoactive intestinal polypeptide on gastric acid secretion is predominantly mediated by somatostatin. 167 56

Activation of the formyl peptide chemoattractant receptor (FPCR) of phagocytic cells mobilizes intracellular calcium stores and affects the plasma membrane potential. Affinity crosslinking of FPCR has demonstrated a 60-80 kDa glycoprotein, with core peptide of 32 kDa. It is not known whether functional FPCR is this single peptide or requires multiple subunits. We used Xenopus oocyte expression system to determine the size of mRNA required for synthesis of functional FPCR. Injection of oocytes with poly(A)+ RNA from HL60 cells differentiated to the granulocyte phenotype resulted in acquisition of formyl peptide-specific responses (inward transmembrane current with a reversal potential consistent with a chloride conductance, and calcium efflux). FPCR activity expressed in oocytes had a ligand concentration dependence, ligand structure dependence and pertussis toxin sensitivity similar to those reported in phagocytic cells. When RNA was size fractionated, a single peak of FPCR activity at 2 kilobases was observed after injection of mRNA into oocytes. Our data strongly suggest that FPCR is composed of a single-sized polypeptide.
 ...
PMID:The formyl peptide chemoattractant receptor is encoded by a 2 kilobase messenger RNA. Expression in Xenopus oocytes. 169 Jan 50

Stimulation of phagocytic cells with micromolar concentrations of extracellular ATP primes the production of toxic oxygen metabolites in response to chemoattractants and independently activates a secretory response in vitro. It is hypothesized that extracellular ATP derived from platelet storage granules and damaged endothelium at sites of localized tissue damage or infection may potentiate the pro-inflammatory effects of phagocytic cells in vivo. ATP-dependent functional responses in the phagocyte appear to be due to stimulation of putative P2 purinoreceptors that are coupled to the activation of a phospholipase C via a pertussis toxin-sensitive G-protein. The existence in nature of at least four subtypes of P2 purinoreceptors has been proposed based on the rank order of potency of nucleotide analogs of ATP studied in a variety of cell types. However, no studies involving the structural identification and characterization of the putative receptors have been reported. We have used the Xenopus oocyte expression system to demonstrate acquired adenosine 5'-(thio) triphosphate (ATP gamma S) responsiveness in oocytes injected with mRNA from the promyelocytic leukemia cell line HL60 by measuring the accelerated efflux of intracellular calcium. Two peaks of ATP gamma S responsiveness (Peak I and Peak II) were detected in sucrose gradient fractionated RNA that corresponded to transcript sizes of 4 and 6 kilobases and that were distinct from a third peak previously shown to be enriched in formyl peptide chemoattractant receptor activity. Peak I and Peak II RNA endowed receptor activity in the oocyte that was pharmacologically indistinguishable: ADP and AMP were inactive whereas UTP and ITP exhibited activity that was similar in potency to that of ATP gamma S. Both Peak I and Peak II ATP gamma S-dependent activity was inhibited by pertussis toxin. These data strongly support the concept of phagocytic cell receptors for extracellular nucleotide triphosphates whose ligand specificity is distinct from all other previously described P2 purinoreceptor subtypes, with the exception of the P2 receptor described in Ehrlich ascites tumor cells, by virtue of the ineffectiveness of ADP as a stimulus. These receptors are most likely composed of a single polypeptide chain that can be expressed in the Xenopus oocyte in a functional form regulated by a pertussis toxin-sensitive G-protein.
 ...
PMID:Characterization of phagocyte P2 nucleotide receptors expressed in Xenopus oocytes. 169 46

The gene coding for the filamentous hemagglutinin (FHA), one of the main factors involved in mediating adherence of Bordetella pertussis to ciliated host cells, was cloned in Escherichia coli, and the 3,500-base-pair nucleotide sequence encoding the amino-terminal region was determined. Molecular cloning, together with the characterization of recombinant FHA-related proteins produced in E. coli, revealed that the primary translation product is a protein of about 370 kilodaltons (kDa). The mature 220-kDa FHA polypeptide secreted by B. pertussis is most probably generated by proteolytic processing that eliminates a carboxy-terminal portion of about 150 kDa. The 1,087 amino-terminal residues of the predicted FHA sequence showed a number of remarkable features. Extensive homology to the Serratia marcescens and Proteus mirabilis hemolysin proteins was found between amino acids 91 and 205 of the FHA sequence, suggesting involvement of this FHA domain in host cell binding or secretion of FHA from B. pertussis. In addition, two regions containing repetitive amino acid sequences were identified. One region, extending from residues 382 to 664, was formed by six repeats, and a second, extending from residues 701 to 912, contained three repeats. The reactivities of several recombinant FHA-derived proteins with a panel of monoclonal antibodies identified at least four epitopes composing an immunoreactive domain present in the carboxy-terminal moiety of the mature FHA.
 ...
PMID:Cloning, partial sequence, expression, and antigenic analysis of the filamentous hemagglutinin gene of Bordetella pertussis. 169 34

The demand for a safer pertussis vaccine has led to the development of acellular vaccine products. We have sought to manufacture a component vaccine based upon the genetic inactivation of pertussis toxin derived by recombinant DNA technology and protein engineering. Rational site-directed mutagenesis of the S1 subunit of pertussis toxin has resulted in an enzymatically-deactivated polypeptide which retains its immunogenic potential. Mutagenic analysis of the other subunits of this toxin has permitted a delineation of the structural determinants involved in its recognition of cellular receptors. The in vitro assembly of holotoxin species possessing selectively engineered subunits may facilitate the production of a molecularly-defined genetic toxoid for pertussis prophylaxis.
 ...
PMID:The molecular engineering of pertussis toxoid. 177 36

The activity of adenylyl cyclase (AC) is controlled by its interaction with receptor-regulated G proteins. The efficiency to form cyclic AMP is strongly influenced by the amount, the subspecies and function of these regulatory proteins. An impairment of AC function has been shown to occur in sarcolemmal preparations (SL) of hearts exposed to either local or global ischaemia. To examine the contribution of G protein function to this phenomenon, cholera toxin (CT)-catalysed ADP-ribosylation of Gs and pertussis toxin (PT)-catalysed ADP-ribosylation of G proteins have been investigated in SL of porcine hearts exposed to global ischaemia for 15-45 min. ADP-ribosylation by CT of an approximately 45 kDa polypeptide was 0.46 +/- 0.06 and ADP-ribosylation by PT of three 39-41 kDa polypeptides was 4.77 +/- 0.77 pmol mg-1 protein in SL of non-ischaemic myocardium. Whereas no change was observed in CT-catalyzed ribosylation after 30 min of ischaemia, there was a reduction in PT-catalyzed ADP-ribosylation to 3.7 +/- 0.35 pmol mg-1 protein after 30 min of ischaemia. Prolongation of ischaemia to 45 min did not reduce further ADP-ribosylation capacity. Quantitative immunoblotting of PT-sensitive G proteins suggests that the diminution of ADP-ribosylation occurred because of a loss of alpha-subunits of G0, Gi-1, and Gi-2 from sarcolemmal membranes.
 ...
PMID:G protein function in the ischaemic myocardium. 180 34

A DNA encoding the human alpha 2-C10 adrenergic receptor was transfected into Rat 1 fibroblasts and clones selected on the basis of resistance to G418 sulfate. Two clones, one of which (1C) expressed some 3.5 pmol/mg membrane protein of the receptor as assessed by the specific binding of [3H]yohimbine and one (4D) which did not express detectable amounts of the receptor were selected for further study. When cholera toxin-catalyzed ADP-ribosylation was performed with [32P]NAD on membranes of these cells in the absence of added guanine nucleotides, radioactivity was incorporated into a polypeptide(s) of 40 kDa in addition to the 45- and 42-kDa forms of Gs alpha. Addition of the selective alpha 2 receptor agonist U.K.14304 enhanced markedly, in a dose-dependent manner, the cholera toxin-catalyzed [32P]ADP-ribosylation of the 40-kDa polypeptide(s), but not the 45- or 42-kDa polypeptides, in membranes of the 1C cells. Dose response curves for U.K.14304 enhancement of cholera toxin-labeling of the 40-kDa polypeptide(s) and stimulation of high affinity GTPase activity were identical. By contrast, U.K.14304 was ineffective in either assay in membranes from the 4D cells, demonstrating this effect to be dependent upon receptor activation. Furthermore, the alpha 2 receptor antagonist yohimbine blocked all effects of U.K.14304. The agonist promotion of cholera toxin-catalyzed ADP-ribosylation of Gi was completely blocked by guanine nucleotides. Whether GDP or GDP + fluoroaluminate (as a mimic of GTP) was used, blockade of the agonist effect was complete and indeed both conditions prevented agonist-independent labeling by cholera toxin of the 40-kDa polypeptide(s). Mg2+ produced an agonist-independent cholera toxin-catalyzed [32P]ADP-ribosylation of the 40-kDa polypeptide(s) but even in the presence of [Mg2+], agonist-stimulation of cholera toxin-labeling of the 40-kDa polypeptide(s) was observed and was additive with the effect of [Mg2+]. Agonist stimulation of cholera toxin-catalyzed ADP-ribosylation of Gi was completely attenuated by pretreatment of the cells with pertussis toxin, which prevents contact between receptors and G-proteins which are substrates for this toxin. By contrast, pretreatment of the cells with concentrations of cholera toxin able to "down-regulate" essentially all of the membrane-associated Gs alpha did not prevent agonist stimulation of cholera toxin-catalyzed ADP-ribosylation of Gi.(ABSTRACT TRUNCATED AT 400 WORDS)
 ...
PMID:Agonist-dependent, cholera toxin-catalyzed ADP-ribosylation of pertussis toxin-sensitive G-proteins following transfection of the human alpha 2-C10 adrenergic receptor into rat 1 fibroblasts. Evidence for the direct interaction of a single receptor with two pertussis toxin-sensitive G-proteins, Gi2 and Gi3. 184 55

An invasive form of the CaM-sensitive adenylyl cyclase from Bordetella pertussis can be isolated from bacterial culture supernatants. This isolation is achieved through the use of QAE-Sephadex anion-exchange chromatography. It has been demonstrated that the addition of exogenous Ca2+ to the anion-exchange gradient buffers will affect elution from the column and will thereby affect the isolation of invasive adenylyl cyclase. This is probably due to a Ca2(+)-dependent interaction of the catalytic subunit with another component in the culture supernatant. Two peaks of adenylyl cyclase activity are obtained. The Pk1 adenylyl cyclase preparation is able to cause significant increases in intracellular cAMP levels in animal cells. This increase occurs rapidly and in a dose-dependent manner in both N1E-115 mouse neuroblastoma cells and human erythrocytes. The Pk2 adenylyl cyclase has catalytic activity but is not cell invasive. This material can serve, therefore, as a control to ensure that the cAMP which is measured is, indeed, intracellular. A second control is to add exogenous CaM to the Pk1 adenylyl cyclase preparation. The 45-kDa catalytic subunit-CaM complex is not cell invasive. Although the mechanism for membrane translocation of the adenylyl cyclase is unknown, there is evidence that the adenylyl cyclase enters animal cells by a mechanism distinct from receptor-mediated endocytosis. Calmodulin-sensitive adenylyl cyclase activity can be removed from preparations of the adenylyl cyclase that have been subjected to SDS-polyacrylamide gel electrophoresis. This property of the enzyme has enabled purification of the catalytic subunit to apparent homogeneity. The purified catalytic subunit from culture supernatants has a predicted molecular weight of 45,000. This polypeptide interacts directly with Ca2+ and this interaction may be important for its invasion into animal cells. Finally, the technique for purifying the catalytic subunit by SDS-polyacrylamide gel electrophoresis may prove useful in studying the interaction of the adenylyl cyclase with other components produced by the bacteria, as well as the interaction of the enzyme with eukaryotic target cells.
 ...
PMID:Purification and assay of cell-invasive form of calmodulin-sensitive adenylyl cyclase from Bordetella pertussis. 185 26

A procedure is described for purification of pertussis heat-labile toxin (PEHLT) from cells of Bordetella pertussis. The purification procedure, performed in the cold and in the presence of protease inhibitors, gives 1,350-fold purification with yields of about 60%. The toxin was shown to be a single-chain polypeptide of 140 kDa, pI 6.02. It was completely inactivated by heating at 56 degrees C for 60 min. Rabbit antiserum prepared against PEHLT neutralized the toxin and gave a single precipitin line on immunodiffusion. In immunodiffusion assays, this anti-PEHLT serum did not react with pertussis toxin, filamentous hemagglutinin, or preparations of pertussis adenylate cyclase. Purified PEHLT elicited dermonecrosis and atrophy of the spleen. PEHLT is extraordinarily active; 0.4 X 10(-12) g caused necrotic lesions in newborn mice, and with 18- to 20-g mice the 50% lethal dose was about 11 X 10(-9) g.
 ...
PMID:Purification and characterization of the heat-labile toxin of Bordetella pertussis. 189 74

Antisera were raised to a synthetic peptide which represents the predicted C-terminal decapeptide of the alpha subunit of the G-proteins Gq and G11. Competitive ELISA indicated that antiserum CQ2 displayed strong reactivity against this peptide. Antiserum CQ2 identified an apparently single polypeptide of 42 kDa which was expressed widely. The mobility of this polypeptide in SDS-PAGE was not modified by pretreatment of cells with pertussis toxin, indicating that it was not a substrate for this toxin. Furthermore, the levels and mobility of this polypeptide were unaltered by treatment of cells with cholera toxin, defining that it was not related to Gs alpha.
 ...
PMID:Widespread distribution of Gq alpha/G11 alpha detected immunologically by an antipeptide antiserum directed against the predicted C-terminal decapeptide. 190 88


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>