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Updated: Aug 15, 2026

Spatio-Temporal Manipulation of Small GTPase Activity at Subcellular Level and on Timescale of Seconds in Living Cells
10:27

Spatio-Temporal Manipulation of Small GTPase Activity at Subcellular Level and on Timescale of Seconds in Living Cells

Published on: March 9, 2012

Msb4p, a protein involved in Cdc42p-dependent organization of the actin cytoskeleton, is a Ypt/Rab-specific GAP

S Albert1, D Gallwitz

  • 1Department of Molecular Genetics, Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany.

Biological Chemistry
|August 11, 2000
PubMed

Insights

Researchers identified Msb4p/Gyp4p, a new GTPase-activating protein (GAP) that regulates Ypt/Rab proteins involved in protein transport. This protein may play a role in polarized secretion.

Area of Science:

  • Molecular Biology
  • Cell Biology
  • Biochemistry

Background:

  • Ypt/Rab proteins, part of the Ras superfamily, are crucial regulators of protein transport via exocytosis and endocytosis.
  • These proteins possess intrinsic GTPase activity, which is significantly enhanced by GTPase-activating proteins (GAPs).

Purpose of the Study:

  • To identify and characterize a novel Ypt/Rab-specific GTPase-activating protein (GAP).
  • To investigate the enzymatic activity and potential function of the newly identified Msb4p/Gyp4p.

Main Methods:

  • Protein purification of Msb4p/Gyp4p.
  • Assays to determine the GTPase-activating activity of Msb4p/Gyp4p on various Ypt/Rab proteins.

Main Results:

  • Msb4p/Gyp4p shares homology in its catalytic domain with other known Gyp family members.
  • Purified Msb4p/Gyp4p demonstrates significant GTPase-activating activity, primarily on Sec4p, Ypt6p, and Ypt7p.

Conclusions:

  • Msb4p/Gyp4p is a novel Ypt/Rab-specific GAP.
  • The findings suggest a potential role for Msb4p/Gyp4p in regulating polarized secretion through its interaction with specific Ypt/Rab proteins.

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