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)

Three G proteins from human brain membranes were purified to near homogeneity by conventional techniques including preparative electrophoresis. These G proteins were characterized by their ability to bind GTP, GDP and GTP analogs. Two of these proteins have molecular weights of 50,000 (G50) and 36,000 (G36), as determined on SDS-gels. G36 was ADP-ribosylated by pertussis toxin. Thus, G50 could represent a Gs alpha subunit, whereas G36 could be Gi alpha or Go alpha. G50 was phosphorylated by cAMP dependent protein kinase and protein kinase C. G36 was phosphorylated by a protein kinase independent of calcium and phospholipid, a proteolytic product of protein kinase C, analogous to protein kinase M. Phosphorylation of G36 by this protein kinase induced a dramatic decrease in its GTPase activity. The third G protein, of molecular weight 22,000 probably belongs to the group of monomeric G proteins possessing functional similarities with ras gene products. The regulation of G proteins involving calcium-dependent and independent pathways is delineated.
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PMID:Purification and characterization of G proteins from human brain: modification of GTPase activity upon phosphorylation. 178 75

Activation of the membrane-associated NADPH oxidase in intact human neutrophils requires a receptor-associated heterotrimeric GTP-binding protein that is sensitive to pertussis toxin. Activation of this NADPH oxidase by arachidonate in a cell-free system requires an additional downstream pertussis toxin-insensitive G protein (Gabig, T. G., English, D., Akard, L. P., and Schell, M. J. (1987) (J. Biol. Chem. 262, 1685-1690) that is located in the cytosolic fraction of unstimulated cells (Gabig, T. G., Eklund, E. A., Potter, G. B., and Dykes, J. R. (1990) J. Immunol. 145, 945-951). In the present study, immunodepletion of G proteins from the cytosolic fraction of unstimulated neutrophils resulted in a loss of the ability to activate NADPH oxidase in the membrane fraction. The activity in immunodepleted cytosol was fully reconstituted by a partially purified fraction from neutrophil cytosol that contained a 21-kDa GTP-binding protein. Purified human recombinant Krev-1 p21 also completely reconstituted immunodepleted cytosol whereas recombinant human H-ras p21 or yeast RAS GTP-binding proteins had no reconstitutive activity. Rabbit antisera raised against a synthetic peptide corresponding to the effector region of Krev-1 (amino acids 31-43) completely inhibited cell-free NADPH oxidase activation, and this inhibition was blocked by the synthetic 31-43 peptide. An inhibitory monoclonal antibody specific for ras p21 amino acids 60-77 (Y13-259) had no effect on cell-free NADPH oxidase activation. Activation of the NADPH oxidase in intact neutrophils by stimulation with phorbol myristate acetate caused a marked increase in the amount of membrane-associated antigen recognized by 151 antiserum on Western blot. Thus a G protein in the cytosol of unstimulated neutrophils antigenically and functionally related to Krev-1 may be the downstream effector G protein for NADPH oxidase activation. This system represents a unique model to study molecular interactions of a ras-like G protein.
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PMID:Resolution of a low molecular weight G protein in neutrophil cytosol required for NADPH oxidase activation and reconstitution by recombinant Krev-1 protein. 190 90

To investigate the relationship between the effects of a pertussis toxin-inhibitable class of G-proteins and the ras family of protooncogenes on cell growth, we isolated multiple cell lines transformed by oncogenic Hras or Nras genes and measured the ability of pertussis toxin to inhibit their growth rate. Although all of the cell lines were morphologically transformed and could grow in agar suspension, there was considerable variability in their resistance to pertussis toxin, ranging from cell lines completely resistant to pertussis toxin to cell lines as sensitive to pertussis toxin as the parental cells from which they derived. For those lines resistant to pertussis toxin, this resistance is not due to an inability of pertussis toxin to reach or react with its intracellular target; pertussis toxin could be shown to ADP-ribosylate the endogenous G-proteins of all lines tested regardless of whether it affected their growth rate. There was a strong correlation between the level of active ras protein expressed in the different lines and the degree of resistance to pertussis toxin (r = 0.80). Although the Hras-transformed cell lines were more resistant to pertussis toxin as a group than the Nras-transformed cell lines, we believe that this is not a primary difference between Nras and Hras, but, rather, is due to a higher average level of expression of ras in the cell lines receiving Hras. We suggest that the consequences of ras transformation vary with the concentration of oncogenic ras present in the cell, and that different assays or different properties of transformation show different sensitivities to the level of ras expression.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effect of ras-gene transformation on the inhibition of NIH3T3 cell growth by pertussis toxin. 194 6

In BALB/c 3T3 cells pretreated with platelet-derived growth factor (PDGF) and epidermal growth factor (EGF) (primed-competent cells), insulin-like growth factors I and II (IGF-I and IGF-II) bind to their own receptors (IGF-IR and IGF-IIR) and stimulate calcium influx and DNA synthesis by a mechanism involving a 40-kDa pertussis toxin substrate. In contrast, these IGFs do not act on unprimed quiescent cells. In this study, the 40-kDa pertussis toxin substrate was identified as Gi-2 alpha using anti-G protein antibodies. We analyzed the quality of signal transduction from IGF-II to Gi-2 alpha. There was no difference in the amount of Gi-2 alpha between quiescent and primed-competent cells, and both of these cells had similar Kd values and numbers of IGF-II-binding sites. Whereas IGF-II did not alter pertussis toxin-catalyzed ADP-ribosylation of Gi-2 alpha in quiescent cells, IGF-II reduced the pertussis toxin substrate activity by 35-50% via the IGF-IIR in primed-competent cells. The action of IGF-II lasted for up to 3 h when IGF-II was present in the medium, and it disappeared when IGF-II was removed. These results suggest that the signaling pathway triggered by IGF-II is uncoupled between the IGF-IIR and Gi-2 alpha in quiescent cells and that PDGF and EGF restore the IGF-IIR-Gi-2 coupling. This study also indicates that low concentrations of IGF-I reduce the pertussis toxin substrate activity of Gi-2 alpha in primed-competent cells in a time course slower than that of IGF-II, but not at all in quiescent cells. However, both of these cells had similar Kd values and numbers of IGF-I binding sites. Therefore, the IGF-I signaling pathway may also be uncoupled between the IGF-IR and Gi-2 alpha in quiescent cells and restored by PDGF and EGF. In BALB/c 3T3 cells transfected with temperature-sensitive Kirsten sarcoma virus bearing the v-Ki-ras gene (ts cells), a 40-kDa pertussis toxin substrate was also identified as Gi-2 alpha. In nonpermissive ts cells, IGF-II was without effect on the pertussis toxin substrate activity of Gi-2 alpha or on calcium influx.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Regulation of transmembrane signal transduction of insulin-like growth factor II by competence type growth factors or viral ras p21. 198 36

Native membranes from human erythrocytes contain the following G proteins which are ADP-ribosylated by a number of bacterial toxins: Gi alpha and Go alpha (pertussis toxin), Gs alpha (cholera toxin), and three proteins of 27, 26 and 22 kDa (exoenzyme C3 from Clostridium botulinum). Three additional C3 substrates (18.5, 16.5 and 14.5 kDa) appeared in conditions of unrestrained proteolysis during hemolysis. SDS-PAGE separation of erythrocyte membrane proteins followed by electroblotting and incubation of nitrocellulose sheets with radiolabeled GTP revealed consistently four GTP-binding proteins with Mr values of 27, 26, 22 and 21 kDa. Although a 22 kDa protein was immunochemically identified as ras p21, the C3 substrate of 22 kDa is a different protein probably identifiable with a rho gene product. Accordingly, at least five distinct small molecular weight guanine nucleotide-binding proteins, whose functions are so far undetermined, are present in native human erythrocyte membranes.
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PMID:Multiple small molecular weight guanine nucleotide-binding proteins in human erythrocyte membranes. 210 17

Transducin, a GTP-binding protein involved in phototransduction in the vertebrate retina, belongs to a family of homologous coupling proteins that also includes Gs and Gi, the regulatory proteins of adenylate cyclase. Here we report the cDNA sequence and deduced amino acid sequence of transducin's alpha subunit (T alpha). The cDNA was isolated, by screening with an antibody probe, from a bovine retinal cDNA library in the expression vector lambda gt11. The 2.2-kilobase cDNA insert hybridized to a single 2.6-kilobase poly(A)+ RNA species present in extracts of bovine retina but not of bovine heart, liver, or brain. The nucleotide sequence of the cDNA revealed an open reading frame long enough to encode the entire 39-kDa T alpha polypeptide. The polypeptide sequence deduced from the cDNA would be composed of 350 amino acids and have a molecular weight of 39,971. Portions of the sequence matched reported amino acid sequences of T alpha tryptic fragments, including sites specifically ADP-ribosylated by cholera and pertussis toxins. The predicted sequence also includes four segments, ranging from 11 to 19 residues in length, that exhibit significant homology to sequences of GTP-binding proteins, including the ras proteins of man and yeast and the elongation factors of ribosomal protein synthesis in bacteria, EF-G and EF-Tu. In combination with previous functional studies of tryptic fragments of T alpha, the deduced amino acid sequence makes it possible to predict which portions of the polypeptide interact with other molecules involved in retinal phototransduction.
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PMID:Amino acid sequence of the alpha subunit of transducin deduced from the cDNA sequence. 240 55

In the preceding report (Kelvin, D.J., G. Simard, H.H. Tai, T.P. Yamaguchi, and J.A. Connolly. 1989. J. Cell Biol. 108:159-167) we demonstrated that pertussis toxin (PT) blocked proliferation and induced differentiation in BC3H1 muscle cells. In the present study, we have used PT to examine specific growth factor signaling pathways that may regulate these processes. Inhibition of [3H]thymidine by PT in 20% FBS was reversed in a dose-dependent fashion by purified fibroblast growth factor (FGF). In 0.5% FBS, the normally induced increase in creatine kinase (CK) activity was blocked by FGF in both the presence and absence of PT. Similar results were obtained with purified epidermal growth factor (EGF). We subsequently examined the effect of a family of growth factors linked to inositol lipid hydrolysis and found that thrombin, like FGF, would increase [3H]thymidine incorporation and block CK synthesis. However, PT blocked thymidine incorporation induced by thrombin, and blocked the inhibition of CK turn-on in 0.5% FBS by thrombin. The ras oncogene, a G protein homologue, has previously been shown to block muscle cell differentiation in C2 muscle cells (Olson, E.N., G. Spizz, and M.A. Tainsky. 1987. Mol. Cell. Biol. 7:2104-2111); we have characterized a BC3H1 cell line, BCT31, which we transfected with the val12 oncogenic Harvey ras gene. This cell line did not express CK in response to serum deprivation. Whereas [3H]thymidine incorporation was inhibited by 70-80% by increasing doses of PT in control cells, BCT31 cells were only inhibited by 15-20%. ADP ribosylation studies indicate this PT-insensitivity is not because of the lack of a PT substrate in this cell line. Furthermore, PT could not induce CK expression in BCT31 cells as it did in parental cells. We conclude that there are at least two distinct growth factor pathways that play a key role in regulating proliferation and differentiation in BC3H1 muscle cells, one of which is PT sensitive, and postulate that a G protein is involved in transducing signals from the thrombin receptor. We believe that ras functions in the transduction of growth factor signals in the nonPT-sensitive pathway or downstream from the PT substrate in the second pathway.
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PMID:Growth factors, signaling pathways, and the regulation of proliferation and differentiation in BC3H1 muscle cells. II. Two signaling pathways distinguished by pertussis toxin and a potential role for the ras oncogene. 249 22

Cholera and pertussis toxin-sensitive G-proteins were examined using specific immunological probes in wild type NIH3T3 cells and in clones of these cells containing the N-ras gene attached to a promotor where expression either was (T15+) or was not (T15-) induced. The major pertussis toxin sensitive-polypeptide had the immunological characteristics of Gi2. Two distinct forms of Gs alpha (45 and 42 kDa) were identified. Long term over-expression of p21N-ras (T15+ cells) did not alter the levels of Gi2 alpha or of Gs alpha. Pretreatment of NIH3T3 or T15 cells with either pertussis toxin or cholera toxin led to the complete in situ ADP-ribosylation of the respective G-proteins. Modification of Gi2 by pertussis toxin, however, had no inhibitory effect on the ability of bombesin to stimulate the production of inositol phosphates in any of these cells lines. Treatment of these cells with cholera toxin elicited a potent inhibition of the bombesin-stimulated production of inositol phosphates. This could be mimicked, however, by other agents which increase intracellular cyclic AMP concentrations. Cholera toxin treatment did not produce a significant alteration in the number of bombesin receptors on the cell surface. These results suggest that, in the T15 cell line, enhanced coupling of bombesin receptors to a phospholipase C-mediated hydrolysis of inositol phospholipids is either produced directly by p21N-ras or that overexpression of this gene product leads to the enhanced expression or function of a cholera and pertussis toxin-insensitive G-protein which then mediates the effect.
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PMID:Identification of the pertussis and cholera toxin substrates in normal and N-ras transformed NIH3T3 fibroblasts and an assessment of their involvement in bombesin-stimulation of inositol phospholipid metabolism. 249 8

We report the existence of several families of GTP-binding proteins in plasma membranes of Metarhizium anisopliae. Two proteins (18.4 and 24 kDa) resemble mammalian Gn-proteins in their being toxin insensitive, binding [alpha-32P]GTP on nitrocellulose blots of sodium dodecyl sulfate (SDS)-polyacrylamide gels, and also in their immunological properties. Four other proteins (31-38.2 kDa) were similar except that they did not bind [alpha-32P]GTP after treatment with sodium dodecyl sulfate. An 18.2 kDa cholera toxin substrate and three toxin insensitive bands (18.6, 18.8, and 24 kDa) are novel proteins antigenically related both to mammalian G-proteins and ras gene products. An additional 23 kDa pertussis toxin substrate (the major G-protein in a crude mycelial extract) reacted strongly with antisera to G-proteins but not with anti-ras serum. Other substrates ADP ribosylated by cholera toxin or botulinum D toxin were immunologically unreactive. Analysis of the structural and functional characteristics of these multiple GTP-binding proteins will promote a better understanding of signal transduction in fungi.
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PMID:Novel GTP-binding proteins in plasma membranes of the fungus Metarhizium anisopliae. 250 39

Many neurotransmitters and hormones activate receptors that are known to be coupled to their effectors by GTP-binding regulatory proteins, G proteins. Activation of many of these same receptors elicits arachidonate release and metabolism. During the past few years, novel experimental techniques have revealed that in many cells arachidonate release is independent of generation of other second messengers, including inositol phosphates, diacylglycerols, and elevation in free intracellular calcium. Much evidence has accumulated to implicate phospholipase A2 as the enzyme catalyzing arachidonate release, and suggesting that this effector enzyme, too, is activated by G proteins. In neural tissues as well as epithelium, endothelium, contractile and connective tissues, and blood cells, G proteins coupled to receptors for a variety of peptide and nonpeptide neurotransmitters and hormones have been shown to directly activate phospholipase A2. In retinal rod outer segments, transducin is the coupling G protein, but the G proteins coupling receptor activation to phospholipase A2 in other cell types is less clear. Some are pertussis toxin-sensitive, whereas others are not, and evidence exists that the ras gene product G protein may also be coupled to and regulate phospholipase A2.
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PMID:G protein regulation of phospholipase A2. 251 Jul 70


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