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Naunyn-Schmiedeberg's Archives of Pharmacology

, Volume 357, Issue 3, pp 323–330 | Cite as

Influence of Clostridium botulinum C2 toxin on FcɛRI-mediated secretion and tyrosine phosphorylation in RBL cells

  • Ulrike Prepens
  • Holger Barth
  • Jörg Wilting
  • K. Aktories
Original article

Abstract

We studied the effects of the binary Clostridium botulinum C2 toxin on stimulated [3H]serotonin release and protein tyrosine phosphorylation in RBL 2H3 hm1 cells. Actin was specifically ADP-ribosylated by C2 toxin in intact cells resulting in a 2–3 fold increase in antigen- or calcium ionophore (A23187)-induced degranulation. The effects of C2 toxin were time- and concentration-dependent. Toxin treatment, which dramatically changes the morphology of RBL cells, was not sufficient to induce mediator release in the absence of activators of secretion. Antigen- and A23187-stimulated tyrosine phosphorylation of 60–80kDa and 110–120kDa proteins was reduced or blocked after C2 toxin incubation. Treatment of RBL cells with the tyrosine phosphatase inhibitor pervanadate reversed the inhibitory effect of C2 toxin on stimulated protein tyrosine phosphorylation indicating activation of phosphatases by C2 toxin. The data indicate that disassembly of the actin cytoskeleton by C2 toxin facilitates FcɛRI-mediated signal-secretion coupling and suggest a role of the actin cytoskeleton in phosphatase regulation in RBL cells.

Key words Actin ADP-ribosylation Clostridium botulinum C2 toxin FcɛRI-signalling RBL cells Secretion Tyrosine phosphorylation Abbreviations A23187 calcium ionophore A23187 C2I enzyme component of Clostridium botulinum C2 toxin C2II binding component of Clostridium botulinum C2 toxin Cyt. D cytochalasin D DNP-BSA dinitrophenyl-conjugated bovine serum albumin FcɛRI high affinity receptor for IgE G protein GTP-binding protein IgE immunglobulin E PAGE polyacrylamide gel electrophoresis PP2A serin-/threonine-specific protein phosphatase type 2A RBL-2H3 hm1 2H3 hm1 subline of rat basophilic leukemia cells SDS sodium dodecylsulfate 

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Copyright information

© Springer-Verlag Berlin Heidelberg 1998

Authors and Affiliations

  • Ulrike Prepens
    • 1
  • Holger Barth
    • 1
  • Jörg Wilting
    • 2
  • K. Aktories
    • 1
  1. 1.Institut für Pharmakologie und Toxikologie der Albert-Ludwigs-Universität Freiburg, Hermann-Herder-Strasse 5, D-79104 Freiburg, GermanyDE
  2. 2.Anatomisches Institut der Albert-Ludwigs-Universität Freiburg, Lehrstuhl II, D-79104 Freiburg, GermanyDE

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