An integrated model for Gpr124 function in Wnt7a/b signaling among vertebrates

Area of Science:

• Neuroscience
• Molecular Biology
• Evolutionary Biology

Background:

• Wnt7a/b ligands are crucial in the central nervous system.
• The endothelial receptor complex of Reck and Gpr124 specifically binds Wnt7a/b.
• Gpr124 facilitates Wnt7a/b delivery to Frizzled receptors.

Purpose of the Study:

• To elucidate the molecular mechanisms of Gpr124-Frizzled interactions in zebrafish and mammals.
• To investigate the evolutionary changes in Gpr124 function across vertebrates.

Main Methods:

• Comparative analysis of Gpr124 structure and function in zebrafish, mice, and humans.
• Identification of intracellular and extracellular interaction domains.
• Study of molecular mimicry and scaffolding mechanisms.

Main Results:

• Zebrafish Gpr124 utilizes intracellular scaffolds, including Dvl-binding and ETTV motifs, for Frizzled interaction.
• Mammalian Gpr124 employs an intracellular domain-independent mechanism involving transmembrane and extracellular domains.
• Species-specific adaptations in Gpr124 mediate distinct interaction pathways.

Conclusions:

• Gpr124-Frizzled interaction mechanisms have evolved divergently between zebrafish and mammals.
• Evolutionary changes in Gpr124 reflect adaptations for Wnt ligand-specific signaling.
• The Reck-Gpr124 complex plays a conserved yet adaptable role in vertebrate development.