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 hydrolytic activity of microsomal phospholipase D from canine cerebral cortex was measured by a radiochemical assay using 1,2-dipalmitoyl-sn-glycerol-3-phosphoryl[3H]choline and 1-palmitoyl-2-[9,10(n)-3H]palmitoyl-sn-glycerol-3-phosphorylcholine as the exogenous substrates. Of several detergents tested, Triton X-100 was found to be the most effective in allowing expression of phospholipase D hydrolytic activity. The microsomal phospholipase D does not require any metal ion for its hydrolytic activity. Calcium and magnesium were slightly inhibitory between concentrations of 1 and 4 mM, but zinc was greatly inhibitory, causing a loss of greater than 90% activity at the 4 mM concentration. Non-hydrolyzable guanine nucleotide analogues such as guanosine 5'-(3-O-thio)triphosphate and guanyl-5'-yl-(beta, gamma-methylene)diphosphonate but not guanosine 5'-(2-thio)diphosphate were able persistently to stimulate phospholipase D hydrolytic activity at micromolar concentrations. Guanosine 5'-(2-thio)diphosphate was capable of partially blocking guanosine 5'-(3-O-thio)triphosphate stimulation of phospholipase D. Aluminum fluoride was able to cause a two- to threefold increase in hydrolytic activity of the phospholipase D. Cholera toxin had a stimulatory effect on the hydrolytic activity of phospholipase D, whereas islet-activating protein pertussis toxin had no effect. These results indicate that regulation of microsomal phosphatidylcholine phospholipase D activity by the guanine nucleotide-binding protein(s) in canine cerebral cortex may play an important role in signal transduction processes as well as in brain choline metabolism.
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PMID:Guanine nucleotide-binding protein regulation of microsomal phospholipase D activity of canine cerebral cortex. 210 44

G proteins couple receptors for extracellular signals to several intracellular effector systems and play a key role in signalling transduction mechanisms. In particulate preparations of Drosophila melanogaster heads, only one substrate for pertussis toxin at 39-40 kd was detected. This substrate, which showed only one isoform when analysed by isoelectric focusing, was recognized by immunoblotting and immunoprecipitation techniques using a polyclonal antibody against the alpha subunit of the Go protein purified from bovine brain and can be thus considered as a Go-like protein. Antibodies obtained against a carboxy-terminal sequence of the alpha subunit of Go (but not of Gi1 or Gi2) and against an internal sequence shared by all the alpha subunits, were also able to cross-react with the alpha subunit of this protein in insects. We have also studied the Go-like protein in several D.melanogaster mutants, primarily in memory and learning mutants. In these mutants there was a sex-dependent enhancement in pertussis toxin-catalysed ADP-ribosylation with respect to the wild-type. This increase could be attributed in part to an increase in the alpha subunit of the Go-like protein, as revealed by immunoblotting with anti-Go alpha polyclonal antibody. This report constitutes the first evidence for the participation of a Go protein in learning and memory.
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PMID:A Go-like protein in Drosophila melanogaster and its expression in memory mutants. 210 94

A radioactive and photoactivatable derivative of NAD+, 2-azido-[adenylate-32P]NAD+, has been synthesized and used with pertussis toxin to ADP-ribosylate Cys347 of the alpha subunit (alpha T) of GT, the retinal guanine nucleotide-binding protein. ADP-ribosylation of alpha T followed by light activation of the azide moiety of 2-azido-[adenylate-32P]ADP-ribose produced four crosslinked species involving the alpha and gamma subunits of the GT heterotrimer: an alpha trimer (alpha-alpha-alpha), and alpha-alpha-gamma crosslink, an alpha dimer (alpha-alpha), and an alpha-gamma crosslink. The alpha trimer, alpha-alpha-gamma complex, alpha dimer, and alpha-gamma complexes were immunoreactive with alpha T antibodies. The alpha-alpha-gamma and the alpha-gamma complexes were immunoreactive with antisera recognizing gamma subunits. No evidence was found for crosslinking of alpha T to beta T subunits. Hydrolysis of the thioglycosidic bond between Cys347 and 2-azido-[adenylate-32P]ADP-ribose using mercuric acetate resulted in the transfer of radiolabel from Cys347 of alpha T in the crosslinked oligomers to alpha monomers, indicative of intermolecular photocrosslinking, and to gamma monomers, indicative of either intermolecular crosslinked complexes (between heterotrimers) or intramolecular crosslinked complexes (within the heterotrimer). These results demonstrate that GT exists as an oligomer and that ADP-ribosylated Cys347, which is four residues from the alpha T-carboxyl terminus, is oriented toward and in close proximity to the gamma subunit.
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PMID:2-Azido-[32P]NAD+, a photoactivatable probe for G-protein structure: evidence for holotransducin oligomers in which the ADP-ribosylated carboxyl terminus of alpha interacts with both alpha and gamma subunits. 211 Oct 13

Various pharmacological effectors were used to investigate the mechanism of arachidonic acid release by N-formyl-methionyl-leucyl-phenylalanine (fMLP) and platelet-activating factor (PAF) in guinea pig alveolar macrophages. The fMLP- and PAF-stimulated arachidonic acid release (i) was mimicked by sodium fluoride and inhibited by Bordetella pertussis toxin, suggesting the participation of a guanine nucleotide-binding protein; ii) was mimicked by A23187 but was insensitive to the calmodulin inhibitor R24571, making the involvement of a calmodulin-dependent pathway unlikely; and (iii) was mimicked by 12-O-tetra-decanoyl phorbol 13 acetate (TPA) and was, like the TPA-stimulated release, markedly decreased when protein kinase C (PKC) had been down-regulated by TPA (65% decrease) or inhibited by sphingosine, a diacylglycerol-competitive PKC inhibitor shown to completely abolish the enzyme activity from alveolar macrophages at 40 microM. Moreover, PAF and fMLP, under conditions where they stimulated arachidonic acid release, promoted an appreciable, albeit transient, translocation of PKC, suggesting a possible involvement of the enzyme in the agonist-stimulated process. However, staurosporine, another PKC inhibitor decreasing PKC activity from alveolar macrophages by 60% at 20 nM, failed to alter fMLP- and PAF-stimulated release. These data lead us to suggest that fMLP- and PAF-stimulated arachidonic acid release is mediated by mechanisms involving either a staurosporine-insensitive PKC isoform or a sphingosine-sensitive coupling between a pertussis toxin-sensitive guanine nucleotide-binding protein and phospholipase A2. Finally, the fMLP- and PAF-stimulated arachidonic acid release was inhibited by cholera toxin and was, like A23187-stimulated release, potentiated by N-[2-(methylamino)ethyl]-5-isoquinolinesulfonamide dihydrochloride (H8), an exclusive protein kinase A inhibitor in alveolar macrophages, suggesting a negative regulation by protein kinase A.
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PMID:Mechanism of N-formyl-methionyl-leucyl-phenylalanine- and platelet-activating factor-induced arachidonic acid release in guinea pig alveolar macrophages: involvement of a GTP-binding protein and role of protein kinase A and protein kinase C. 211 77

The proximal tubule of the kidney represents an important location where adenylate cyclase regulates salt and water transport; yet a detailed characterization of the distribution and classification of guanine nucleotide-binding protein (G protein) and adenylate cyclase is lacking. We used purified brush border (20-fold) and basolateral membranes (14-fold) to characterize parathyroid hormone- and G protein-regulated adenylate cyclase and G-protein distribution. Adenylate cyclase was predominantly localized to basolateral membranes, while the 46-kDa alpha subunit of the stimulatory G protein (Gs) was 2-fold higher in brush border membranes than in basolateral membranes. The alpha subunit of the inhibitory G protein (Gi; 41 kDa) was equally distributed on immunoblotting but was 2-fold higher in brush border membranes than in basolateral membranes on radiolabeling with pertussis toxin. A 42-kDa cholera toxin substrate that cross-reacted with antisera to the common alpha subunit of G proteins and to Gs on immunoblotting and that was not immunoprecipitated with two Gi antisera was the most abundant alpha subunit and comprised approximately 1% of the total membrane proteins. These observations suggest that G proteins are important regulators of proximal tubular transport independent of adenylate cyclase.
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PMID:Proximal tubular epithelial cells possess a novel 42-kilodalton guanine nucleotide-binding regulatory protein. 212 Jul 2

In Nb2 cell membranes, two guanine nucleotide-binding protein (G-protein) species (Mr 43.5 and 46.5 kD) were [32P]-ADP-ribosylated by cholera toxin, while a single protein (Mr 41.5 kD) was [32P]-ADP-ribosylated by pertussis toxin. Immunostaining indicated two immunoreactive prolactin (PRL) receptor moieties of 56 and 64 kD. Cross-linking with ethylene glyco bis[succinimidyl-succinate] (mol. length of 16.1 A) generated a high mol. wt., [32P]-ADP-ribosylated band of 140-160 kD which also showed immunoreactivity with antiserum to the PRL receptor. Other cross-linkers with shorter molecular lengths (8.6 - 11.4 A) were ineffective. These findings indicate that the Nb2 lactogen receptor is complexed with G-proteins and provide evidence for the role of G-proteins in mediating PRL-stimulated mitognesis in Nb2 cells.
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PMID:Cross-linking of G-proteins to the prolactin receptor in rat NB2 lymphoma cells. 212 15

The selectivity of D2 dopamine receptor-guanine nucleotide-binding protein (G protein) coupling was studied by reconstitution techniques utilizing purified D2 dopamine receptors from bovine anterior pituitary and resolved G proteins from bovine brain, bovine pituitary, and human erythrocyte. Titration of a fixed receptor concentration with varying G protein concentrations revealed two aspects of receptor-G protein coupling. First, Gi2 appeared to couple selectively with the D2 receptor with approximately 10-fold higher affinity than any other tested Gi subtype. Second, the G proteins differed in the maximal receptor-mediated agonist stimulation of the intrinsic GTPase activity. Gi2 appeared to be maximally stimulated by agonist-receptor complex with turnover numbers of approximately 2 min-1. The other Gi subtypes, Gi1 and Gi3, could be only partially activated, resulting in maximal rates of GTPase of approximately 1 min-1. Agonist-stimulated GTPase activity was not detected in preparations containing Go from bovine brain. The differences in maximal agonist-stimulated GTPase rates observed among the Gi subtypes could be explained by differences in agonist-promoted guanyl nucleotide exchange. Both guanosine 5'-3-O-(thio)triphosphate (GTP gamma S) binding and GDP release parameters were enhanced 2-fold for the Gi2 subtype over the other Gi subtypes. These results suggest that even though several types of pertussis toxin substrate may exist in most tissues, a receptor may interact discretely with G proteins, thereby dictating signal transduction mechanisms.
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PMID:Specificity of receptor-G protein interactions. Discrimination of Gi subtypes by the D2 dopamine receptor in a reconstituted system. 213 24

The biochemical pathways through which tumor cell locomotion is mediated are poorly understood. Autocrine motility factor (AMF), which is produced by and stimulates motility in A2058 human melanoma cells, was used to characterize phosphoinositide (PtdIns) metabolism activated in association with tumor cell motility. AMF stimulated up to a 400% increase in de novo incorporation of 3H-myo-inositol into cellular lipids beginning 40 minutes after exposure. In cells prelabeled with 3H-myo-inositol, AMF stimulated a 200% increase in total inositol phosphates (inositol monophosphate, InsP1; inositol bisphosphate, InsP2; inositol trisphosphate, InsP3) after 90 minutes of exposure, with a 300% maximal increase in InsP3 at 120 minutes. InsP1 and InsP2 were maximally increased 130% of control values. Treatment with AMF stimulated a parallel dose-dependent increase in both motility and PtdIns levels. We have shown previously that the A2058 motile response to AMF is inhibited markedly by cell pretreatment with pertussis toxin (PT). Inositol phosphate production was inhibited by a 2-hour pretreatment of cells with PT (0.5 microgram/ml). PT treatment of A2058 membranes was associated with ADP-ribosylation of a 40-kDa protein consistent with the presence of an alpha subunit of a guanine nucleotide-binding protein (G protein). These data indicate that AMF elicits increases in cell motility and phosphoinositide metabolism via a PT-sensitive G protein signal transduction pathway.
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PMID:Autocrine motility factor stimulates a three-fold increase in inositol trisphosphate in human melanoma cells. 215 19

Studies were performed to examine a potential role for a guanine nucleotide-binding protein in epidermal growth factor (EGF)-stimulated phospholipase A2 (PLA2) activity. EGF increased prostaglandin E2 (PGE2) production in intact or saponin-permeabilized rat inner medullary collecting tubule (RIMCT) cells. Incubation of permeabilized cells with guanosine 5'-O-(thiotriphosphate) (GTP gamma S) enhanced and with guanosine 5'-O-(2-thiodiphosphate) (GDP beta S) inhibited the response to EGF. GDP beta S had no effect on ionomycin-stimulated PGE2 production. Exposure of intact cells to 25 mM NaF + 10 microM AlCl3 enhanced both basal and EGF-stimulated PGE2 production. Pertussis toxin ADP-ribosylated a 41-kDa protein in RIMCT cell membranes. Pretreatment of cells with pertussis toxin (100 ng/ml for 16 h) eliminated the response to EGF in intact cells and the response to EGF + GTP gamma S in permeabilized cells. Pertussis toxin had no effect on the response to ionomycin. The effect of pertussis toxin was not due to alterations in cAMP as cellular cAMP levels were unaffected by pertussis toxin both in the basal state and in the presence of EGF. PGE2 production in response to EGF was not transduced by a G protein coupled to phospholipase C (PLC) as neomycin, which inhibited PLC, did not decrease EGF-stimulated PGE2 production. Also, PGE2 production was not increased by inositol trisphosphate and did not require the presence of extracellular Ca2+. In contrast to EGF-stimulated PLC activity, stimulation of PLA2 by EGF was not susceptible to inhibition by phorbol 12-myristate 13-acetate. These results clearly demonstrate the existence of a PLA2-specific pertussis toxin-inhibitable guanine nucleotide-binding protein coupled to the EGF receptor in RIMCT cells.
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PMID:The epidermal growth factor receptor is coupled to a phospholipase A2-specific pertussis toxin-inhibitable guanine nucleotide-binding regulatory protein in cultured rat inner medullary collecting tubule cells. 215 14

Stimulation by fMet-Leu-Phe analogs of GTPase activity in plasma membranes from rabbit neutrophils was compared with the stimulation of degranulation in intact neutrophils. All four formyl peptides examined (fMet-Leu-Phe-Phe, fMet-Leu-Phe, fNle-Leu-Phe, and fVal-Leu-Phe) were full agonists for both responses. Their ED50 values for the two responses correlated well, although those for GTPase stimulation were uniformly about tenfold greater. The specific antagonist tBoc-Phe-Leu-Phe-Leu-Phe competitively inhibited both GTPase activity and degranulation stimulated by fMet-Leu-Phe; its Ki values were similar for the two responses. Pertussis toxin treatment, in contrast, inhibited the maximal stimulation of both responses by fMet-Leu-Phe with minimal shift in ED50. The inhibitory actions of tBoc-Phe-Leu-Phe-Leu-Phe and pertussis toxin on GTPase activity thus paralleled the effects on degranulation. These observations substantiate the hypothesis that a guanine nucleotide-binding protein that is a pertussis toxin substrate couples the formyl peptide receptors to physiological function in the neutrophil.
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PMID:Comparison of stimulation by chemotactic formyl peptide analogs between GTPase activity in neutrophil plasma membranes and granule enzyme release from intact neutrophils. 215 12


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