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 frizzled gene family of putative Wnt receptors encodes proteins that have a seven transmembrane-spanning motif characteristic of G-protein-linked receptors, although no loss-of-function studies have demonstrated a requirement for G-proteins for Wnt signaling by the gene product of frizzled-1. Medium conditioned by mouse F9 teratocarcinoma stem cells stably transfected to express either Xenopus Wnt-5a or Wnt-8 was used to test primitive endoderm formation of F9 stem cells. F9 stem cells expressing the rat Frizzled-1 receptors demonstrated endoderm formation in response to conditioned medium containing Wnt-8 but not to medium containing Wnt-5a. Primitive endoderm formation stimulated by Wnt-8 acting on the rat Frizzled-1 receptor was blocked by treatment with pertussis toxin by depletion of either Galpha(o) or Galpha(q) via antisense oligodeoxynucleotides, as well as by inhibitors of protein kinase C (bisindoylmaleimide) and of mitogen-activated protein kinase kinase (PD98059). Our results demonstrate the requirement for G-protein subunits Galpha(o) (a pertussis toxin substrate) and Galpha(q) for signaling by Frizzled-1, and an obligate role for the protein kinase C (likely mediated through stimulation of Galpha(q)) and mitogen-activated protein kinase network at the level of mitogen-activated protein kinase kinase.
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PMID:Activation of rat frizzled-1 promotes Wnt signaling and differentiation of mouse F9 teratocarcinoma cells via pathways that require Galpha(q) and Galpha(o) function. 1055 39

T cells resistant to the immunosuppressive drug cyclosporin A (CsA) may be important mediators of chronic graft rejection. We previously reported that T cells activated in the presence of endothelial cells (EC) develop resistance to CsA, and initiate IL-2 secretion within 8-12 h of triggering. CsA normally blocks the phosphatase, calcineurin, thus preventing nuclear translocation of the transcription factor, NFAT. We find that in the presence but not the absence of EC, NFAT1 can be detected in the nuclei of CsA-treated T cells within 8 h of triggering, reaching a maximal level of 60% of control by 24 h. Glycogen synthase kinase-3beta (GSK-3beta), which rephosphorylates NFAT and promotes nuclear export, is inhibited by EC costimulation. GSK-3beta is a component of the wnt signaling pathway, and EC express wnt-5a and T cells express frizzled-5, a wnt-5a receptor. Wnt-5a promotes T cell NFAT nuclear accumulation in the presence of CsA, an effect mimicked by Li(+), a potent inhibitor of GSK-3beta. The protein kinase C agonist PMA dramatically synergizes with both EC and wnt-5a in stimulating T cell IL-2 synthesis, and inhibition of either protein kinase C by Ro-31-8425 or G-proteins by pertussis toxin effectively blocks the actions of wnt-5a on T cells. Finally, a secreted, dominant-negative form of frizzled-5 blocks EC-mediated CsA resistance. Thus, EC promote CsA-resistant nuclear localization of NFAT and subsequent IL-2 synthesis through a noncanonical wnt-dependent pathway.
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PMID:Endothelial cells stimulate T cell NFAT nuclear translocation in the presence of cyclosporin A: involvement of the wnt/glycogen synthase kinase-3 beta pathway. 1224 65

The collagen-induced phosphorylation of discoidin domain receptor 1 (DDR1) in Wnt-5a-expressing HB2 mammary cells was effectively inhibited by pertussis toxin, but not by cholera toxin or antibodies blocking beta(1) integrins. Moreover, pertussis toxin reduced adhesion of the cells to collagen by approximately 50%, and antibodies against beta(1) integrins had a similar effect that was in fact additive to that of pertussis toxin. Cholera toxin had accordingly no such effect on adhesion. By comparison, pertussis toxin did not influence adhesion of Wnt-5a-antisense HB2 cells or MCF-7 mammary tumor cells, neither of which express Wnt-5a or exhibit activation of DDR1. In accordance with these results, direct mastoparan-induced activation of G-proteins in Wnt-5a-deficient MCF-7 cells enabled collagen-induced phosphorylation of DDR1 and enhanced their adhesion. The inactive analogue mastoparan-17 had no such effects on MCF-7 cells nor did active mastoparan affect adhesion of Wnt-5a-expressing HB2 cells. A possible explanation for how DDR1, a receptor tyrosine kinase (RTK), potentiates mammary cell adhesion comes from our observations that pertussis toxin also inhibited the recruitment of the cytoskeletal regulator phosphatidylinositol 3-kinase (PI3K) to DDR1 as well as its phosphorylation/activation. In accordance with that, the PI3K inhibitor wortmannin significantly impaired adhesion of normal Wnt-5a-expressing HB2 cells but had little effect on adhesion of Wnt-5a-antisense HB2 cells. Thus, a G(i/o)-protein signaling pathway mediates the effect of Wnt-5a expression by enabling collagen-induced activation of DDR1, which, in parallel with beta(1) integrins, regulates adhesion of mammary cells.
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PMID:Wnt-5a and G-protein signaling are required for collagen-induced DDR1 receptor activation and normal mammary cell adhesion. 1247 17