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Ggamma13 interacts with PDZ domain-containing proteins
Zairong Li1, Outhiriaradjou Benard, Robert F Margolskee
1Department of Neuroscience, Mount Sinai School of Medicine, New York, New York 10029, USA.
The Journal of Biological Chemistry
|February 14, 2006
Summary
The G protein gamma13 subunit (Ggamma13) interacts with PDZ domain proteins like PSD95 and SAP97 via its C-terminal CAAX tail. This interaction may localize Ggamma13 to specific cellular signaling complexes.
Area of Science:
- Molecular Biology
- Cellular Signaling
- Neuroscience
Background:
- The G protein gamma13 subunit (Ggamma13) is crucial for taste signal transduction and found in neuronal tissues.
- PDZ domain proteins are known scaffolds in cellular signaling pathways.
- Understanding Ggamma13 interactions is key to elucidating its role in cellular functions.
Purpose of the Study:
- To identify binding partners of Ggamma13.
- To characterize the interaction between Ggamma13 and PDZ domain proteins.
- To investigate the mechanism and physiological relevance of these interactions.
Main Methods:
- Yeast two-hybrid assays to screen for binding partners.
- Pull-down assays to confirm physical interactions.
- Coimmunoprecipitation to validate endogenous interactions in native tissues.
- Site-directed mutagenesis to identify interaction domains.
Main Results:
- Ggamma13 specifically binds to PDZ domains of PSD95, Veli-2, and SAP97.
- The C-terminal CAAX tail of Ggamma13 mediates its interaction with PSD95.
- Mutating the CAAX tail abolished Ggamma13 binding to PSD95.
- Endogenous interactions between Ggamma13 and PSD95/SAP97 were confirmed in brain and taste tissues.
Conclusions:
- This study reveals a novel interaction between Ggamma13 and PDZ domain proteins via the Ggamma subunit's CAAX tail.
- This interaction provides a mechanism for targeting Gbetagamma subunits to specific subcellular locations.
- The findings offer new insights into the regulation of G protein signaling pathways.