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Updated: Jun 26, 2026
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A Kinetic Fluorescence-based Ca2+ Mobilization Assay to Identify G Protein-coupled Receptor Agonists, Antagonists, and Allosteric Modulators
Published on: February 20, 2018
The fifth class of Galpha proteins
Yuichiro Oka1, Luis R Saraiva, Yen Yen Kwan
1Institut für Genetik der Universität zu Köln, Zülpicherstrasse 47, D-50674 Köln, Germany.
Summary
Researchers discovered a fifth class of Galpha proteins, named Gv, which is ancient and found across diverse animal species. This finding expands our understanding of G protein evolution and its diverse roles in biology.
Area of Science:
- Molecular Biology
- Evolutionary Biology
- Biochemistry
Background:
- Heterotrimeric G proteins are crucial signaling molecules in vertebrates, classified into four main families: Gs, Gi, Gq, and G12.
- Orthologs of these G protein alpha-subunits are found in sponges, indicating their ancient evolutionary origins.
Purpose of the Study:
- To report the discovery and characterization of a novel, fifth class of Galpha protein, designated Gv.
- To investigate the evolutionary history, conservation, and genomic features of the Gv protein family.
Main Methods:
- Bioinformatic analysis of genomic and protein sequences across various animal phyla.
- Phylogenetic analysis to determine evolutionary relationships.
- Gene expression analysis using RT-PCR and in situ hybridization in zebrafish.
Main Results:
- Identified a fifth Galpha protein class, Gv, with members present in sponges and conserved across many animal lineages, exhibiting a birth-and-death evolutionary pattern.
- Gv proteins possess conserved GTP-binding motifs and unique amino acid residues, suggesting specific interaction partners.
- Genomic structure of Gv genes is distinct from other Galpha classes, and Gv shows significant homology among vertebrate members, evolving under negative selection.
Conclusions:
- The discovery of the Gv protein class significantly alters the established classification of G proteins.
- Gv represents an ancient and conserved signaling pathway with a unique evolutionary trajectory.
- Further research into Gv function is warranted to understand its specific roles in animal physiology and development, particularly in tissues like the inner ear.
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