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Multiple sequence elements facilitate Chp Rho GTPase subcellular location, membrane association, and transforming
Emily J Chenette1, Natalia Y Mitin, Channing J Der
1Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7295, USA.
Molecular Biology of the Cell
|April 28, 2006
Summary
Cdc42 homologous protein (Chp) uses unique carboxy-terminal basic amino acids for membrane association, unlike other Rho GTPases. This distinct mechanism regulates Chp
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- Cdc42 homologous protein (Chp) is a Rho family GTPase.
- Chp associates with cellular membranes via palmitoylation, distinct from prenylation used by other Rho GTPases.
Purpose of the Study:
- To investigate the carboxy-terminal residues that facilitate Chp's membrane association.
- To understand the regulatory mechanisms of Chp subcellular localization and function.
Main Methods:
- Site-directed mutagenesis to assess the role of carboxy-terminal residues.
- Analysis of Chp subcellular localization using cell imaging techniques.
- Evaluation of Chp transforming activity.
- Investigation of Chp regulation by tumor necrosis factor-alpha and Rho GTPase inhibitors.
Main Results:
- Chp membrane association and transforming activity depend on a stretch of basic amino acids in its carboxy terminus.
- The 11 carboxy-terminal residues alone are sufficient for Chp plasma and endomembrane association.
- Tumor necrosis factor-alpha specifically activates endomembrane-associated Chp.
- Chp membrane association is not inhibited by Rho guanine nucleotide dissociation inhibitory proteins.
Conclusions:
- Chp utilizes unique carboxy-terminal sequence elements for membrane localization, expanding the regulatory mechanisms of Rho GTPases.
- These findings highlight novel pathways for controlling Rho GTPase function and cellular localization.