Dissection of thymocyte signaling pathways by in vivo expression of pertussis toxin ADP-ribosyltransferase

EMBO J. 1990 Dec;9(12):3821-9.

Abstract

Stimulation of the T lymphocyte antigen receptor-CD3 complex (TCR-CD3) causes T cell activation by a process associated with increased phosphatidylinositol-specific phospholipase C (PI-PLC) activity. Evidence exists suggesting that GTP-binding (G) proteins, particularly the pertussis toxin (PT)-sensitive Gi proteins, participate in this signal transduction pathway. To clarify the role of Gi proteins in TCR-CD3 signaling, and to investigate other possible functions of Gi molecules in T cells, we expressed the S1 subunit of PT in the thymocytes of transgenic mice using the lymphocyte-specific lck promoter. Transgenic thymocytes contained S1 activity and exhibited profound depletion of Gi protein PT substrates in a manner suggesting their inactivation by S1 in vivo. Nevertheless, treatment of transgenic thymocytes with mitogenic stimuli provoked normal increases in intracellular free Ca2+ concentrations and IL-2 secretion, indicating that Gi proteins are not required for T cell activation. These normal signaling responses notwithstanding, mature thymocytes accumulated in lck-PT mice and did not appear in secondary lymphoid organs or in the circulation. Viewed in the context of the known features of Bordetella pertussis infection, our results suggest that a PT-sensitive signaling process, probably involving Gi proteins, regulates thymocyte emigration.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Base Sequence
  • Calcium / physiology
  • Cells, Cultured
  • Flow Cytometry
  • GTP-Binding Proteins / metabolism
  • Humans
  • Interleukin-2 / biosynthesis
  • Lymphocyte Activation
  • Mice
  • Mice, Transgenic
  • Molecular Sequence Data
  • NAD / metabolism
  • Oligonucleotide Probes
  • Pertussis Toxin
  • Poly(ADP-ribose) Polymerases / genetics*
  • Signal Transduction*
  • T-Lymphocytes / enzymology
  • T-Lymphocytes / immunology*
  • Virulence Factors, Bordetella / genetics
  • Virulence Factors, Bordetella / metabolism

Substances

  • Interleukin-2
  • Oligonucleotide Probes
  • Virulence Factors, Bordetella
  • NAD
  • Poly(ADP-ribose) Polymerases
  • Pertussis Toxin
  • GTP-Binding Proteins
  • Calcium