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Published on: February 20, 2018
Accessory proteins for G proteins: partners in signaling
Motohiko Sato1, Joe B Blumer, Violaine Simon
1Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA.
Annual Review of Pharmacology and Toxicology
|January 13, 2006
Summary
New accessory proteins, including Activators of G protein Signaling (AGS), provide receptor-independent input to heterotrimeric G proteins. These proteins reveal novel G protein regulation and diverse signaling roles.
Area of Science:
- Cellular signaling
- Molecular biology
- Biochemistry
Background:
- Heterotrimeric G proteins are central to signal transduction, typically activated by G protein-coupled receptors (GPCRs).
- Accessory proteins traditionally modulate GPCR-mediated signaling strength, specificity, and complex formation.
- Recent discoveries highlight accessory proteins functioning independently of cell surface receptors.
Purpose of the Study:
- To investigate a novel class of accessory proteins that regulate G protein signaling.
- To characterize receptor-independent activators of G protein signaling (AGS) and related proteins.
- To explore the expanded functional roles and regulatory mechanisms of G proteins.
Main Methods:
- Functional screens for receptor-independent G protein activators.
- Protein interaction screens.
- Genetic screens in model organisms.
Main Results:
- Identification of Activators of G protein Signaling (AGS) proteins.
- Discovery of accessory proteins acting as alternative binding partners for G protein subunits.
- Evidence for novel G protein regulation independent of canonical receptor pathways.
- Demonstration of accessory proteins influencing nucleotide exchange and subunit interactions.
- Observation of complexes formed independent of the typical G(alpha)G(betagamma) heterotrimer.
Conclusions:
- Accessory proteins, including AGS, represent a significant expansion of known G protein regulators.
- These proteins offer novel mechanisms for G protein activation and modulation outside of GPCRs.
- G protein subunits exhibit unexpected diversity as signal transducers, mediated by these accessory factors.
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