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XL alpha s is a new type of G protein

R H Kehlenbach1, J Matthey, W B Huttner

  • 1Institute for Neurobiology, University of Heidelberg, Germany.

Nature
|December 22, 1994
PubMed

Insights

Researchers discovered a new cholera toxin target, extra large G protein (XL alpha s), which regulates secretory vesicle formation at the trans-Golgi network. This protein may mediate cholera toxin

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Biochemistry

Background:

  • GTP-binding proteins regulate cellular functions, including vesicular transport.
  • Cholera toxin ADP-ribosylates the alpha s subunit of heterotrimeric G proteins, stimulating secretory vesicle formation from the trans-Golgi network.

Purpose of the Study:

  • To identify new cholera toxin targets involved in secretory vesicle formation.
  • To characterize the role of a novel 'extra large' G protein (XL alpha s) in cellular secretion.

Main Methods:

  • Identification and characterization of XL alpha s.
  • Localization studies of XL alpha s within the cell.
  • Correlation of XL alpha s presence with secretory pathway types.

Main Results:

  • A novel 92K 'extra large' G protein (XL alpha s) was identified as a new cholera toxin target.
  • XL alpha s is specifically associated with the trans-Golgi network.
  • XL alpha s is selectively found in cells utilizing both regulated and constitutive secretion pathways.

Conclusions:

  • XL alpha s is a novel target of cholera toxin.
  • XL alpha s may play a crucial role in mediating the effects of cholera toxin on secretory vesicle formation.
  • The localization and selective presence of XL alpha s suggest its involvement in regulating protein secretion pathways.

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