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)

Acquired renal cysts derive from terminally differentiated tubular epithelium in adults as a consequence of increased epithelial cell proliferation, fluid accumulation and extracellular matrix remodelling. To understand better how human epithelial cysts may be initiated and progressively expand, cells from primary cultures of normal human adult renal cortex were dispersed in polymerized type I collagen. The transparent matrix permitted repeated observation by light microscopy of cyst formation from individual renal cells. The cyst cells reacted strongly with distal nephron histochemical markers (cytokeratin antibodies AE1/AE3, epithelial membrane antigen, and Arachis hypogaea lectin) but inconsistently or not at all to markers of proximal tubules (Tetragonolobus purpureas lectin and Phaseolus vulgaris erthroagglutinin lectin). The number of spherical, fluid-filled epithelial cysts that developed in a standardized microscope field quantified cyst initiation. Cyst progression was determined from the increase in the diameter (surface area) of cysts and represents a hyperplastic event. EGF or TGF alpha, were required in serum-free defined medium to cause cysts to develop from individual epithelial cells dispersed in the matrix; insulin was required as a co-factor. The EC50 for EGF was approximately 0.1 ng/ml, and for insulin 1 microgram/ml. Early cultures of normal cortex formed cysts more efficiently when dispersed in collagen matrix than cells passaged several times before suspension in the gel. Agonists of adenylate cyclase (PGE1, AVP, VIP, PTH, forskolin, cholera toxin), methylisobutylxanthine, and 8-Br-cAMP, though incapable of causing cyst formation alone in defined medium, enhanced cyst initiation and progression in the presence of EGF and insulin. Angiotensin II, TNF alpha, beta-estradiol, and pertussis toxin had no effect in the absence or presence of EGF and insulin. Pertussis toxin inhibited cyst initiation and expansion caused by EGF and forskolin but potentiated cyst initiation and expansion caused by EGF and PGE1. Cyst formation and expansion were inhibited by TGF beta 1 and 2-chloroadenosine. Polarized monolayers of human renal cortical cells grown on permeable membranes were used to independently quantify the effects of agonists on the net secretion of solute and water from the basolateral to the apical surface of the cells. PGE1, forskolin, and 8-Br-cAMP stimulated net fluid secretion that was sustained for several days; EGF enhanced forskolin-stimulated fluid secretion. We conclude that the formation and expansion of in vitro cysts derived from solitary human cortex cells depends on the coordinated interplay between cellular proliferation and fluid secretion.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:In vitro formation and expansion of cysts derived from human renal cortex epithelial cells. 131 21

Regulatory GTP-binding proteins (G proteins) are membrane-attached heterotrimers (alpha, beta, gamma) that mediate cellular responses to a wide variety of extracellular stimuli. They undergo a cycle of guanine-nucleotide exchange and GTP hydrolysis, during which they dissociate into alpha-subunit and beta gamma complex. The roles of G-protein alpha-subunits in these processes and for the specificity of signal transduction are largely established; the beta- and gamma-subunits are essential for receptor-induced G-protein activation and seem to be less diverse and less specific. Although the complementary DNAs for several beta-subunits have been cloned, isolated subunits have only been studied as beta gamma complexes. Functional differences have been ascribed to the gamma-subunit on the basis of extensive sequence similarity among beta-subunits and apparent heterogeneity in gamma-subunit sequences. Beta gamma complexes can interact directly or indirectly with different effectors. They seem to be interchangeable in their interaction with pertussis toxin-sensitive alpha-subunits, so we tested this by microinjecting antisense oligonucleotides into nuclei of a rat pituitary cell line to suppress the synthesis of individual beta-subunits selectively. Here we show that two out of four subtypes of beta-subunits tested (beta 1 and beta 3) are selectively involved in the signal transduction cascades from muscarinic M4 (ref. 4) and somatostatin receptors, respectively, to voltage-dependent Ca2+ channels.
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PMID:Different beta-subunits determine G-protein interaction with transmembrane receptors. 132 98

Guanine nucleotide-binding proteins (G proteins) transduce signals from agonist- and light-sensitive receptors. In the visual excitation system, the photon receptor rhodopsin is coupled to the G protein Gt (transducin). Gt is composed of alpha, beta, and gamma subunits; the alpha subunit binds guanine nucleotide, whereas the beta and gamma subunits, which are tightly associated, appear to facilitate interaction of alpha with receptor and pertussis toxin-catalyzed ADP-ribosylation of alpha. To study the function of transducin, monoclonal antibodies were developed against the purified protein. Monoclonal antibody 2H3 reacted with Gt gamma but not G gamma from bovine brain or rabbit liver. In the absence of photolyzed rhodopsin, both intact 2H3 and Fab fragments of 2H3 were able to inhibit completely, in a concentration-dependent manner, ADP-ribosylation of transducin by pertussis toxin 2H3 had no effect on ADP-ribosylation in the presence of photolyzed rhodopsin. The GTPase activity of transducin, which is dependent on rhodopsin, was inhibited only 50% by 2H3. These data are consistent with the hypotheses that an epitope recognized by 2H3 may be important in the formation of the alpha beta gamma complex or that interaction of 2H3 with gamma may alter conformation of the latter and, thereby, inhibit complex formation. Further, reactions of gamma with 2H3 appear to be prevented by interaction with rhodopsin, suggesting that its interaction either shields or alters the epitope recognized by 2H3.
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PMID:Immunological characterization of guanine nucleotide-binding proteins: effects of a monoclonal antibody against the gamma subunit of transducin on guanine nucleotide-binding protein-receptor interactions. 169 60

The guanine nucleotide binding proteins (G proteins) that couple hormone and other receptors to a variety of intracellular effector enzymes and ion channels are heterotrimers of alpha, beta, and gamma subunits. One way to study the interfaces between subunits is to analyze the consequences of chemically cross-linking them. We have used 1,6-bismaleimidohexane (BMH), a homobifunctional cross-linking reagent that reacts with sulfhydryl groups, to cross-link alpha to beta subunits of Go and Gi-1. Two cross-linked products are formed from each G protein with apparent molecular masses of 140 and 122 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Both bands formed from Go reacted with anti-alpha o and anti-beta antibody. The mobility on sodium dodecyl sulfate-polyacrylamide gel electrophoresis is anomalous since the undenatured, cross-linked proteins have the same Stokes radius as the native, uncross-linked alpha beta gamma heterotrimer. Therefore, each cross-linked product contains one alpha and one beta subunit. Activation of Go by guanosine 5'-3-O-(thio)triphosphate (GTP gamma S) does not prevent cross-linking of alpha to beta gamma, consistent with an equilibrium between associated and dissociated subunits even in the presence of GTP gamma S. The same cross-linked products of Go are formed in brain membranes reacted with BMH as are formed in solution, indicating that the residues cross-linked by BMH in the pure protein are accessible when Go is membrane bound. Analysis of tryptic peptides formed from the cross-linked products indicates that the alpha subunit is cross-linked to the 26-kDa carboxyl-terminal portion of the beta subunit. The cross-linked G protein is functional, and its alpha subunit can change conformation upon binding GTP gamma S. GTP gamma S stabilizes alpha o to digestion by trypsin (Winslow, J.W., Van Amsterdam, J.R., and Neer, E.J. (1986) J. Biol. Chem. 261, 7571-7579) and also stabilizes the alpha subunit in the cross-linked product. Cross-linked G o can be ADP-ribosylated by pertussis toxin. This ADP-ribosylation is inhibited by GTP gamma S with a concentration dependence that is indistinguishable from that of the control, uncross-linked G o. These two kinds of experiments indicate that alpha o is able to change its conformation even though it cannot separate completely from beta gamma. Thus, although dissociation of the subunits accompanies activation of G o in solution, it is not obligatory for a conformational change to occur in the alpha subunit.
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PMID:Structural and functional studies of cross-linked Go protein subunits. 189 68

Alveolar macrophages (AM) migrate less well in response to chemotactic ligands than do monocytes and neutrophils. The response of monocytes and neutrophils to chemotactic ligands is mediated at least in part by pertussis toxin-sensitive guanine nucleotide binding proteins (Gi proteins). Whether this is also true in AM is uncertain. We hypothesized that decreased chemotaxis by AM was due in part to diminished Gi protein and/or chemotactic receptor density in AM. G proteins are heterotrimers made up of alpha, beta, and gamma subunits; the predominant pertussis toxin-sensitive Gi proteins are those containing alpha i2 or alpha i3 subunits. Pertussis toxin pretreatment (0.5 microgram/ml) significantly reduced AM, monocyte, and neutrophil chemotaxis to N-formyl-L-methionyl-L-leucyl-L-phenylalanine (FMLP) and human zymosan-activated serum (P less than 0.05). However, as previously noted, AM chemotaxis was much less than that observed in monocytes and neutrophils. Immunoblots using antibodies that are specific for alpha i2 and alpha i3 showed that AM contained approximately 3-fold less alpha i2 and approximately 10-fold less alpha i3 per microgram of plasma membrane protein than did monocytes or neutrophils. Similar results were obtained in immunoblots made using antibodies to common alpha subunit determinants and to the beta 36 subunit. A comparable approximately 4-fold reduction in density of receptors for [3H]FMLP was found in AM compared to neutrophils. The diminished density of Gi proteins and FMLP receptors was not due to a generally decreased density of plasma membrane proteins in AM, since the density of the membrane-associated tyrosine kinase hck was similar in AM, monocytes, and neutrophils.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Signal transduction in human alveolar macrophages: diminished chemotactic response to FMLP correlates with a diminished density of Gi proteins and FMLP receptors. 190 89

1. The adenosine receptor (P1-purinoceptor) agonists N6-cyclopentyladenosine and N-5'-ethyl-carboxamidoadenosine at concentrations up to 10 mumols 1(-1) affected neither basal, nor noradrenaline- and angiotensin II-stimulated formation of inositol-1-phosphate, inositol-1,4-bisphosphate, and inositol-1,4,5-trisphosphate in slices of rat renal cortex. 2. In contrast, adenine nucleotides (P2-purinoceptor agonists) markedly stimulated inositol phosphate formation. The observed rank order of potency adenosine-5'-O-(2-thiodiphosphate) (EC50 39 mumols 1(-1] greater than adenosine-5'-O-(3-thiotriphosphate) (587) greater than or equal to 5'-adenylylimidodiphosphate (App(NH)p, 899) greater than adenylyl-(beta, gamma-methylene)-diphosphate (4,181) was consistent with the interaction of the compounds with the P2Y-subtype of P2-purinoceptors. AMP and the ADP analogue (alpha, beta-methylene)-adenosine-5'-diphosphate were ineffective. ATP and ADP (less than or equal to 10 mmol 1(-1] did not produce a consistent increase, owing to their hydrolytic degradation in the incubation medium. 3. Whereas the inositol phosphate response to App(NH)p was linear only up to 5 min incubation, the time-dependent stimulation of noradrenaline declined at a slower rate. Following pre-exposure of the renal cortical slices to App(NH)p, renewed addition of App(NH)p caused no further enhancement in the accumulation of inositol phosphates, whilst noradrenaline was still capable of eliciting a response. This suggests that the apparent loss of responsiveness to App(NH)p is not due to substrate depletion or enzymatic inactivation, but most likely attributable to homologous desensitization of the purinoceptor. 4. Pretreatment of the animals with pertussis toxin caused a substantial reduction of functional Gi-protein, as indicated by the lack of [32P]-NAD incorporation in a membrane preparation of the renal cortex. Nevertheless, the increase in inositol phosphate formation induced by noradrenaline, angiotensin II, and App(NH)p was not significantly impaired. 5. We conclude that P2 gamma-purinoceptors are present in the renal cortex; these receptors stimulate formation of inositol phosphates via a pertussis toxin-insensitive pathway and undergo homologous desensitization. On the other hand, our results suggest that renal A,-adenosine receptors do not use stimulation of phosphoinositide breakdown as a transmembrane signalling system.
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PMID:P2-, but not P1-purinoceptors mediate formation of 1, 4, 5-inositol trisphosphate and its metabolites via a pertussis toxin-insensitive pathway in the rat renal cortex. 211 89

1. Bull-frog dorsal root ganglion cells in primary culture were voltage clamped in the whole-cell configuration. The pipette solution contained ATP (5 mM). 2. Step depolarizations (5-70 mV, 0.1-1 s) from a holding potential close to the resting potential (range, -64 to -79 mV) evoked a non-inactivating potassium current with properties indistinguishable from those which have been reported for the M-current of bull-frog sympathetic neurones. 3. An unhydrolysable ATP analogue APP(NH)P (5 mM), substitute with ATP in the pipette solution, did not support the M-current activation. 4. Bath application of ATP (30 nM-30 microM) reduced the amplitude of the M-current in a concentration-dependent manner, congruent to 50% inhibition of the current occurring with 1 microM-ATP. The main effect of ATP was to reduce the maximum M-conductance without changing the activation and deactivation kinetics of the M-current. 5. Essentially the same results were obtained with ADP (0.1-30 microM) and alpha, beta-methylene-ATP (10-30 microM). AMP (10-100 microM) and adenosine (10-30 microM) were without effect on the M-current. 6. The ATP-induced inhibition of the M-current was irreversible when an unhydrolysable GTP analogue GTP-gamma-S (10-30 microM) was present in the pipette solution. ATP (3 microM) reduced the amplitude of the M-current only by about 10% when GDP-beta-S (100 microM) was present in the pipette solution. Pre-treatment of the cells with pertussis toxin (IAP; 500 ng ml-1) for 24 h at 24 degrees C did not prevent the ATP-induced M-current inhibition. 7. Phorbol 12-myristate 13-acetate (PMA; 1-3 microM) reduced the amplitude of the M-current to about 50%. A reduction in the M-current amplitude by PMA (3 microM) and ATP (10 microM) was attenuated when staurosporine (200 nM) was present in the pipette solution. Forskolin (10 microM) was without effect on the M-current. 8. It is concluded that ATP acting at P2 receptors, associated with an IAP-insensitive GTP-binding protein, inhibits the M-current in amphibian primary afferent neurones.
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PMID:ATP regulates muscarine-sensitive potassium current in dissociated bull-frog primary afferent neurones. 212 60

Stimulation of P2-purinergic receptors by ATP resulted in activation of phosphorylase, which was associated with marked production of inositol trisphosphate (Ins-P3), in rat hepatocytes. ATP also inhibited forskolin-induced accumulation of cAMP in the presence of a phosphodiesterase inhibitor. On the contrary, adenosine or AMP never inhibited the cAMP accumulation, but increased hepatocyte cAMP; the stimulation was antagonized by a methylxanthine. Thus, P1-purinergic receptors are linked to adenylate cyclase in a stimulatory fashion in hepatocytes. Various kinds of purine nucleotides stimulating P2-receptors can be divided into two groups on the basis of their relative abilities to stimulate Ins-P3 production and to inhibit cAMP accumulation; the first group including adenosine 5'-O-(3-thiotriphosphate) (ATP gamma S), ADP, 5-adenylyl imidodiphosphate, GTP, and guanosine 5'-O-(3-thiotriphosphate) has an efficacy similar to that of ATP, and the second group of nucleotides including alpha, beta-methyleneadenosine 5'-triphosphate, beta, gamma-methyleneadenosine 5'-triphosphate (App(CH)2)p), and GDP exerts considerable inhibitory effects on cAMP accumulation, but only slight effects on inositol lipid metabolism. Treatment of hepatocytes with islet-activating protein, pertussis toxin, blocked the nucleotide-induced inhibition of cAMP accumulation, but exerted only a small effect on Ins-P3 production. In membranes prepared from hepatocytes, forskolin-stimulated adenylate cyclase was inhibited by GTP. This GTP-induced inhibition of the enzyme was susceptible to islet-activating protein and dependent on the concentration of ATP (or its derivatives, ATP gamma S or App(CH2)p). It is concluded that there are two types of P2-purinergic receptors: one is linked to adenylate cyclase via an inhibitory guanine nucleotide regulatory protein (Gi) and the other is linked to phospholipase C.
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PMID:P2-purinergic receptors are coupled to two signal transduction systems leading to inhibition of cAMP generation and to production of inositol trisphosphate in rat hepatocytes. 244 92

The predominant guanine nucleotide-binding protein (G-protein) of bovine lung membranes, termed GL, has been purified and compared biochemically, immunochemically and functionally with Gi and Go purified from rabbit brain. The purified GL appeared to have a similar subunit structure to Gi and Go, being composed of alpha, beta and possibly gamma subunits. On Coomassie Blue-stained SDS/polyacrylamide gels and immunoblots, the alpha subunit of GL (GL alpha) displayed an intermediate mobility (40 kDa) between those of Gi and Go (Gi alpha and Go alpha). GL alpha was [32P]ADP-ribosylated in the presence of pertussis toxin and [32P]NAD+. Analysis of [32P]ADP-ribosylated alpha subunits by SDS/polyacrylamide-gel electrophoresis and isoelectric focusing showed that GL alpha was distinct from Gi alpha and Go alpha, but very similar to the predominant G-protein in neutrophil membranes. Immunochemical characterization also revealed that GL was distinct from Gi and Go, but was indistinguishable from the G-protein of neutrophils, which has been tentatively identified as Gi2 [Goldsmith, Gierschik, Milligan, Unson, Vinitsky, Maleck & Spiegel (1987) J. Biol. Chem. 262, 14683-14688]. In functional studies, higher Mg2+ concentrations were required for guanosine 5'-[gamma-[35S]thio]triphosphate (GTP[35S]) binding to GL than were required for nucleotide binding to Go, whereas Gi showed a Mg2+-dependence similar to that of GL. The kinetics of GTP[35S] binding to GL was quite different from those of Gi and Go; t1/2 values of maximal binding were 30, 15 and 5 min respectively. In contrast, the rate of hydrolysis of [gamma-32P]GTP by GL (t1/2 approximately 1 min) was approx. 4 times faster than that by Gi or Go. These results indicated that the predominant G-protein purified from lung is structurally and functionally distinct from Gi and Go of brain, but structurally indistinguishable from Gi2 of neutrophils.
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PMID:Purification and characterization of predominant G-protein from bovine lung membranes. Biochemical and immunochemical comparison with Gi1 and Go purified from brain. 249 37

Signal transduction across biological membranes is modulated by a family of related GTP-binding proteins termed G proteins. These G proteins have a heterotrimeric structure composed of alpha, beta, and gamma subunits. The alpha subunits of the G proteins bind GTP and appear to determine the biochemical specificity of the protein. We have recently cloned and characterized cDNA encoding two G-protein alpha subunits, alpha i and alpha h. The former is a substrate for ADP-ribosylation by pertussis toxin. The protein corresponding to alpha h has not yet been identified. These cDNAs encode proteins, which demonstrate 90% sequence identity to one another and also show marked similarity to other G proteins. The present studies were designed to determine whether the genes for these related proteins are clustered on a single human chromosome. Genomic DNA isolated from a panel of mouse-human hybrid cell lines was analyzed by hybridization to cDNAs for alpha i and alpha h. Based on the distribution patterns of alpha i and alpha h in cell hybrids, the gene for alpha i was assigned to human chromosome 7, and the gene for alpha h assigned to chromosome 12. These data suggest that the G-protein gene family may be distributed over at least two human chromosomes.
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PMID:Genes for two homologous G-protein alpha subunits map to different human chromosomes. 282 34


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