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Updated: Nov 10, 2025
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Spatio-Temporal Manipulation of Small GTPase Activity at Subcellular Level and on Timescale of Seconds in Living Cells
Published on: March 9, 2012
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Arf1 orchestrates Rab GTPase conversion at the trans-Golgi network
Laura L Thomas1, Carolyn M Highland1, J Christopher Fromme1
1Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853.
Molecular Biology of the Cell
|March 31, 2021
Summary
Rab GTPases organize membrane trafficking and organelle identity. Arf1 GTPase regulates Rab conversion at the trans-Golgi network by recruiting TRAPPII and Gyp1, ensuring distinct Rab domains.
Area of Science:
- Cell Biology
- Molecular Biology
- Membrane Trafficking
Background:
- Rab GTPases are crucial for membrane trafficking and maintaining organelle identity.
- The yeast Golgi complex exhibits distinct Rab domains, with Ypt1/Rab1 and Ypt6/Rab6 at early/medial Golgi, transitioning to Ypt31/32/Rab11 at the late Golgi/trans-Golgi network (TGN).
- Previous models proposed GTPase-activating protein (GAP) cascades, involving Ypt31/32 recruiting Gyp1 and Gyp6, to explain this Rab conversion.
Purpose of the Study:
- To investigate additional regulatory mechanisms governing Rab transition at the TGN.
- To elucidate the role of the TRAPPII complex and Arf1 GTPase in Rab inactivation at the TGN.
Main Methods:
- Experimental validation of the TRAPPII complex's role in Ypt6 inactivation.
- Investigation of Arf1 GTPase's function in recruiting Gyp1 for Ypt1 inactivation at the TGN.
Main Results:
- Confirmed the TRAPPII complex as a key regulator of Ypt6 inactivation.
- Uncovered a novel role for Arf1 GTPase in recruiting Gyp1 to inactivate Ypt1 at the TGN.
- Demonstrated that Arf1 acts as a master regulator of Rab conversion by recruiting TRAPPII and Gyp1.
Conclusions:
- Rab transition at the TGN involves complex regulatory layers beyond previously known GAP cascades.
- Arf1 GTPase is a central coordinator of Rab conversion, essential for maintaining Golgi compartment identity.
- These findings provide new insights into the precise control of membrane trafficking and organelle organization.
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