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Interaction of 14-3-3 protein with regulator of G protein signaling 7 is dynamically regulated by tumor necrosis

Thomas Benzing1, Michael Köttgen, Marc Johnson

  • 1Renal Division and Center for Clinical Research, University Hospital Freiburg, Hugstetterstrasse 55, 79106 Freiburg, Germany.

The Journal of Biological Chemistry
|June 22, 2002
PubMed

Insights

Tumor necrosis factor-alpha (TNF-α) dynamically regulates RGS7 protein activity by altering its phosphorylation state, affecting interactions with 14-3-3 proteins and modulating G protein signaling pathways.

Area of Science:

  • Molecular and Cellular Biology
  • Signal Transduction
  • Neuroscience

Background:

  • Regulators of G protein signaling (RGS) proteins are crucial for deactivating Gαi and Gαq subunits.
  • 14-3-3 proteins bind phosphorylated RGS proteins, inhibiting their GTPase-accelerating activity.
  • RGS7's interaction with 14-3-3 is dependent on serine 434 phosphorylation.

Purpose of the Study:

  • To investigate the dynamic regulation of RGS7 phosphorylation by TNF-α.
  • To determine how TNF-α-mediated signaling affects the interaction between RGS7 and 14-3-3.
  • To elucidate the functional consequences of this interaction on G protein-coupled inwardly rectifying K+ (GIRK) channel activity.

Main Methods:

  • Phosphorylation analysis of RGS7 serine 434 in response to TNF-α stimulation.
  • Co-immunoprecipitation assays to assess RGS7 and 14-3-3 protein interactions.
  • Electrophysiological recordings in Xenopus oocytes to measure GIRK channel activity.

Main Results:

  • TNF-α stimulation transiently decreased RGS7 serine 434 phosphorylation.
  • This decrease abrogated the inhibitory interaction between RGS7 and 14-3-3 proteins.
  • 14-3-3 inhibited wild-type RGS7 function, but not RGS7(P436R) or RGS4, which do not bind 14-3-3.

Conclusions:

  • Extracellular signals, such as TNF-α, can modulate RGS protein activity.
  • This modulation occurs through regulating the phosphorylation-dependent interaction with 14-3-3 proteins.
  • This represents a novel mechanism for controlling G protein signaling kinetics.

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