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)

Tyrosine phosphorylation is known to regulate the formation of focal adhesions in cells adhering to extracellular matrix (ECM). We have investigated the possible involvement of tyrosine phosphorylation and the focal adhesion kinase (FAK) in the cytoskeletal changes induced by serum or lysophosphatidic acid (LPA) in quiescent Swiss 3T3 fibroblasts. As shown previously by others, quiescent cells stimulated with serum or LPA reveal a rapid reappearance of focal adhesions and stress fibers. Here we show that this is accompanied by an increase in phosphotyrosine in focal adhesions and specifically an increase in the tyrosine phosphorylation of FAK. The LPA-stimulated reappearance of focal adhesions and stress fibers is blocked by inhibitors of phospholipase C but not by pertussis toxin (PTX), indicating that this LPA signaling pathway is mediated by phospholipase C activation and does not involve PTX-sensitive G proteins. In the absence of serum or LPA, these cytoskeletal effects and the tyrosine phosphorylation of FAK can be mimicked by sodium orthovanadate in conjunction with hydrogen peroxide, agents that inhibit protein tyrosine phosphatases and thereby elevate levels of phosphotyrosine. Two tyrosine kinase inhibitors, erbstatin and genistein block both the serum-induced tyrosine phosphorylation of FAK and the assembly of focal adhesions and stress fibers. Two other tyrosine kinase inhibitors, tyrphostins 47 and 25, previously shown to inhibit FAK, failed to prevent FAK phosphorylation or the reassembly of focal adhesions and stress fibers in response to serum. However, these inhibitors did prevent FAK phosphorylation and cytoskeletal assembly in response to lysophosphatidic acid (LPA), one component of serum previously shown to stimulate assembly of focal adhesions and stress fibers. Our findings suggest that the response to serum is complex and that although FAK phosphorylation is important, other tyrosine kinases may also be involved.
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PMID:Tyrosine phosphorylation is involved in reorganization of the actin cytoskeleton in response to serum or LPA stimulation. 770 13

In the endothelial cell line EAhy 926, 1-oleoyl-lysophosphatidic acid (LPA) stimulated the tyrosine phosphorylation of the pp42 isoform of mitogen-activated protein (MAP) kinase. Maximum phosphorylation was observed within 5 min of LPA addition, but the response was sustained for up to 120 min. Re-addition of LPA after 60 min stimulated a further sustained increase in the tyrosine phosphorylation of MAP kinase. In cells pretreated with phorbol 12-myristate 13-acetate (PMA; 24 h) or preincubated with the protein kinase C inhibitor Ro-318220, LPA-induced tyrosine phosphorylation of pp42 MAP kinase was substantially reduced at 2 min but potentiated at 60 min. Ro-318220 in combination with either PMA or pertussis toxin pretreatment abolished the LPA response at all time points, suggesting an involvement of protein kinase C in the pertussis toxin-sensitive part of the pathway. Agents which raised intracellular cyclic AMP levels did not affect the initial phase of LPA-stimulated MAP kinase activation, but abolished the late phase. However, this effect was prevented by Ro-318220, implicating a greater role for protein kinase C than protein kinase A in the regulation of sustained MAP kinase responses. LPA stimulated an increase in the tyrosine phosphorylation of focal adhesion kinase pp125 (pp125FAK) in EAhy 926 cells which was both protein kinase C- and pertussis toxin-independent. These results are discussed in terms of the pathways regulating both MAP kinase and pp125FAK in response to LPA in the EAhy 926 endothelial cells line.
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PMID:Regulation of lysophosphatidic acid-stimulated tyrosine phosphorylation of mitogen-activated protein kinase by protein kinase C- and pertussis toxin-dependent pathways in the endothelial cell line EAhy 926. 774 5

The human cholecystokinin (CCK)B/gastrin receptor was stably transfected into Rat1 fibroblasts to examine the signaling pathways mediated by this seven-transmembrane, G protein-linked receptor. We report here that binding of CCK-8 or gastrin to the CCKB/gastrin receptor induced phosphoinositide breakdown and led to a rapid, transient, and concentration-dependent increase in intracellular Ca2+, which was completely blocked by a specific CCKB receptor antagonist. The peptides also stimulated tyrosine phosphorylation of focal adhesion kinase (p125FAK) and paxillin. Both CCK-8 and gastrin induced a dose- and time-dependent activation of MAP kinase and p74raf-1 kinase in the transfected Rat1 cells. These effects could be dissociated from protein kinase C activation and were not dependent on a functional Gi protein. Finally, both CCK-8 and gastrin induced DNA synthesis in Rat1 cells transfected with the human CCKB/gastrin receptor through a pertussis toxin-insensitive pathway. These results indicate that the neuropeptides gastrin and CCK can activate multiple signal transduction pathways and act as sole mitogens by binding to the CCKB/gastrin receptor transfected into Rat1 fibroblasts.
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PMID:The human CCKB/gastrin receptor transfected into rat1 fibroblasts mediates activation of MAP kinase, p74raf-1 kinase, and mitogenesis. 779 6

Infectious disease processes follow the initial steps of adherence of the organism to host tissues and subsequent colonization of the target tissues that can occur through specific adhesion-receptor systems. Bordetella pertussis, the human pathogen that causes whooping cough, has evolved a genetically controlled system whereby adhesins are expressed when they enter the human host. Two adhesins, filamentous hemagglutinin (FHA) and pertactin, mediate the adherence of the bacterium to eukaryotic cells through varied attachment mechanisms, including lectin-like binding sites that interact with sulfated sugars on cell surface glycoconjugates and the ARG-GLY-ASP binding sequence, which recognizes a family of integrins found on the cell surface. The differential expression of relevant receptors by various eukaryotic cells likely plays a role in the pathogenesis and immune response to the bacterium by the host, directing the organism to specific cell types and to specific tissue sites. Substantial evidence exists that the B. pertussis adhesins, FHA and pertactin, elicit immune responses that are protective in animal models for the disease, including serum antibody production and local immune responses in the respiratory tract following nasal administration of encapsulated antigens. Both of these adhesins are components of new acellular pertussis vaccines that have proven safe and highly effective for prevention of serious disease in infants.
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PMID:Pertussis antigens that abrogate bacterial adherence and elicit immunity. 887 33

Integrin-associated protein (IAP) is a receptor for the carboxyl-terminal "cell-binding domain" (CBD) of thrombospondin 1 (TS1). IAP associates with alpha v beta 3 integrin and mAbs against IAP inhibit certain integrin functions. Here we examine the effects of the TS1 CBD and 4N1K (KRFYVVMWKK), a cell-binding peptide derived from it, on the adhesion and spreading on vitronectin (VN) of C32 human melanoma cells which express IAP, alpha v beta 3, and alpha v beta 5. Cells adhere to VN at low surface densities via alpha v beta 5 and spread very slowly while adhesion to higher density VN involves both alpha v beta 5 and alpha v beta 3 and results in rapid spreading. Spreading of the cells, but not adhesion, on sparse VN coatings is markedly enhanced by the presence of soluble TS1, the recombinant CBD and 4N1K, but not the "mutant" peptide 4NGG, KRFYGGMWKK, which fails to bind IAP. This enhanced spreading is completely blocked by mAb LM609 against alpha v beta 3 and the anti-IAP mAb B6H12. Correlated with this enhanced spreading is increased tyrosine phosphorylation of focal adhesion kinase (FAK), paxillin, and a protein of ca. 90 kD. The enhanced spreading induced by TS1 and 4N1K and the constitutive spreading on higher density VN are both blocked by calphostin C (100 nM), wortmannin (10 nM), and tyrosine kinase inhibitors. In contrast, pertussis toxin specifically blocks only the TS1 stimulated spreading on low density VN, indicating that IAP exerts its effects on signal transduction via a heterotrimeric Gi protein acting upstream of a common cell spreading pathway which includes PI-3 kinase, PKC, and tyrosine kinases.
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PMID:Thrombospondin modulates alpha v beta 3 function through integrin-associated protein. 889 8

We previously demonstrated that in white fat cell precursors alpha2-adrenoceptor stimulation lead to the phosphorylation of p44 and p42 mitogen-activated protein kinases and an increase in cell number. Regulation of cell adhesion and cell cytoskeleton plays a crucial role in the control of cell growth by various growth factors. Here, we report that in mouse 3T3F442A preadipocytes expressing 2500 fmol/mg protein of the human alpha2C10-adrenoceptor (alpha2AF2 cells), alpha2-adrenergic stimulation rapidly restored the spreading of cells previously retracted by serum withdrawal. This effect was pertussis toxin sensitive and was blocked by pretreatment of the cells with dihydrocytochalasin B (a blocker of actin polymerization), genistein (a tyrosine kinase inhibitor), or agents that increase cell cAMP content. Spreading was accompanied by cell membrane ruffling, formation of lamelipodia and filipodia, appearance of focal adhesion plaques, and induction of actin stress fibers. alpha2-Adrenergic stimulation also lead to a rapid Gi- and actin-dependent tyrosine phosphorylation of the pp125 focal adhesion kinase (FAK) as well as of the p42 and p44 mitogen-activated protein kinases. alpha2-Adrenergic-dependent spreading and FAK and mitogen-activated protein kinase phosphorylation were also observed in 3T3F442A preadipocytes permanently expressing 20 fmol/mg protein of the human alpha2C10-adrenoceptor (alpha2AF3 cells) as well as in BFC-1beta preadipocytes, which constitutively express 25 fmol/mg protein of mouse alpha2A-adrenoceptors. In BFC-1beta preadipocytes, alpha2-adrenergic-dependent spreading and pp125FAK phosphorylation were counteracted by beta-adrenergic stimulation. Our results suggest that alpha2-adrenergic control of actin polymerization and focal adhesion assembly could play a crucial role in the regulation of preadipocyte growth by the sympathetic nervous system.
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PMID:alpha2-Adrenoceptor stimulation promotes actin polymerization and focal adhesion in 3T3F442A and BFC-1beta preadipocytes. 894 Mar 38

The experiments presented here were designed to examine the contribution of p125 focal adhesion kinase (p125FAK) tyrosine phosphorylation to the activation of the mitogen-activated protein kinase cascade induced by bombesin, lysophosphatidic acid (LPA), and platelet-derived growth factor (PDGF) in Swiss 3T3 cells. We found that tyrosine phosphorylation of p125FAK in response to these growth factors is completely abolished in cells treated with cytochalasin D or in cells that were suspended in serum-free medium for 30 min. In marked contrast, the activation of p42mapk by these factors was independent of the integrity of the actin cytoskeleton and of the interaction of the cells with the extracellular matrix. The protein kinase C inhibitor GF 109203X and down-regulation of protein kinase C by prolonged pretreatment of cells with phorbol esters blocked bombesin-stimulated activation of p42mapk, p90rsk, and MAPK kinase-1 but did not prevent bombesin-induced tyrosine phosphorylation of p125FAK. Furthermore, LPA-induced p42mapk activation involved a pertussis toxin-sensitive guanylate nucleotide-binding protein, whereas tyrosine phosphorylation of p125FAK in response to LPA was not prevented by pretreatment with pertussis toxin. Finally, PDGF induced maximum p42mapk activation at concentrations (30 ng/ml) that failed to induce tyrosine phosphorylation of p125FAK. Thus, our results demonstrate that p42mapk activation in response to bombesin, LPA, and PDGF can be dissociated from p125FAK tyrosine phosphorylation in Swiss 3T3 cells.
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PMID:Dissociation of mitogen-activated protein kinase activation from p125 focal adhesion kinase tyrosine phosphorylation in Swiss 3T3 cells stimulated by bombesin, lysophosphatidic acid, and platelet-derived growth factor. 897 Jan 51

Integrin-associated protein (IAP or CD47) is a receptor for the cell/platelet-binding domain (CBD) of thrombospondin-1 (TS1), the most abundant protein of platelet alpha granules. Although it associates with alphaIIbbeta3, IAP has no known function in platelets. TS1, the CBD, and an IAP agonist peptide (4N1K) from the CBD of TS1 activate the platelet integrin alphaIIbbeta3, resulting in platelet spreading on immobilized fibrinogen, stimulation of platelet aggregation, and enhanced tyrosine phosphorylation of focal adhesion kinase. Furthermore, 4N1K peptide selectively stimulates the phosphorylation of LYN and SYK and their association with FAK. The phosphorylation of SYK is blocked by pertussis toxin, implicating a Gi-like heterotrimeric G protein. IAP solublized from membranes of unstimulated platelets binds specifically to an affinity column of 4N1K peptide. Both alphaIIb and beta3 integrin subunits and c-Src bind along with IAP. This complex of proteins is also detected with immunoprecipitation. Activation of platelets with the agonist peptide 4N1K results in the association of FAK with the IAP-alphaIIbbeta3 complex. Thus an important function of TS1 in platelets is that of a secreted costimulator of alphaIIbbeta3 whose unique properties result in its localization to the platelet surface and the fibrin clot.
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PMID:Thrombspondin acts via integrin-associated protein to activate the platelet integrin alphaIIbbeta3. 916 39

The Ras-dependent activation of Erk kinases by G protein-coupled receptors (GPCRs) is thought to involve tyrosine phosphorylation of docking proteins that serve as scaffolds for the plasma membrane recruitment of Ras guanine nucleotide exchange factors, such as the Grb2-mSos complex. We have investigated the role of two GPCR-regulated tyrosine phosphoproteins, p125(FAK) (FAK) and Shc, in the Ras-dependent activation of Erk kinases by endogenously expressed GPCRs in Rat 1a fibroblasts. Several lines of evidence suggest that tyrosine phosphorylation of FAK and Shc are independently regulated. The GPCRs for lysophosphatidic acid (LPA), thrombin, and bombesin mediate equivalent increases in FAK tyrosine phosphorylation and FAK-Grb2 association. In contrast, only LPA and thrombin receptors significantly stimulate Shc tyrosine phosphorylation and Shc-Grb2 complex formation. Tyrosine phosphorylation of FAK is pertussis toxin-insensitive, can be mimicked by calcium ionophore, and is inhibited by treatment with cytochalasin D, which depolymerizes the actin cytoskeleton. In contrast, tyrosine phosphorylation of Shc is inhibited by pertussis toxin treatment, is not induced by calcium ionophore, and is insensitive to cytochalasin D. In each case, the rapid stimulation of Erk 1/2 correlates with tyrosine phosphorylation of Shc but not of FAK. The dissociation of FAK-Grb2 complex formation from receptor-mediated activation of Erk 1/2 indicates that recruitment of Grb2-mSos to the plasma membrane is not sufficient to mediate rapid Erk activation. Using four mechanistically distinct inhibitors of clathrin-mediated endocytosis, concanavalin A, hypertonic medium, depletion of intracellular potassium, and monodansylcadaverine, we find that GPCR-mediated Erk 1/2 activation is also endocytosis-dependent. Thus, we propose that an additional step involving vesicle-mediated endocytosis is required for the rapid, Ras-dependent activation of Erk kinases in fibroblasts.
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PMID:G protein-coupled receptors mediate two functionally distinct pathways of tyrosine phosphorylation in rat 1a fibroblasts. Shc phosphorylation and receptor endocytosis correlate with activation of Erk kinases. 939 6

Recent results indicate that a fluoroalumino complex (AlFx) is probably the molecule responsible for the mitogenic effect of fluoride in MC3T3-E1 osteoblast-like cells. Initial analysis suggested that a tyrosine phosphorylation (tyr phos) process similar to that induced by thrombin and activation of the p42 MAP kinase (ERK 2) mediate this cellular response. In the present study, the signaling mechanism activated by AlFx was further investigated. The results indicated that AlFx dose-dependently enhanced the tyr phos of the cell adhesion proteins FAK and paxillin, as well as of the adaptor molecules p46shc, p52shc, and p66shc and their association with GRB2. Pretreatment of MC3T3-E1 cells with cytochalasin D completely prevented FAK and paxillin tyr phos without any alteration in the tyr phos of Shc proteins and activation of ERK2 induced by AlFx. This observation suggests that in confluent MC3T3-E1 cells, there is no link between the activation of FAK induced by AlFx and the stimulation of ERK2. Pretreatment of the cells with pertussis toxin inhibited Shc phosphorylation, activation of ERK2, and markedly reduced cell replication induced by AlFx. This toxin also significantly reduced the stimulation of Pi transport activity induced by AlFx in these cells. Alteration in tyr phos induced by AlFx was not associated with any detectable inhibition of tyrosine phosphatase activity in MC3T3-E1 cell homogenates, suggesting that enhanced tyr phos induced by AlFx probably resulted from activation of a tyrosine kinase. In conclusion, the results of this study suggest that the mitogenic effect of fluoride in MC3T3-E1 osteoblast-like cells is mediated by the activation of a pertussis toxin-sensitive Gi/o protein and suggest an important role for these heterotrimeric G proteins in controlling the growth and differentiation of bone-forming cells.
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PMID:Mechanism of the mitogenic effect of fluoride on osteoblast-like cells: evidences for a G protein-dependent tyrosine phosphorylation process. 942 Dec 30


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