Biased signaling through G-protein-coupled PROKR2 receptors harboring missense mutations

Area of Science:

• Molecular biology
• Genetics
• Endocrinology

Background:

• Kallmann syndrome is linked to mutations in the prokineticin receptor 2 (PROKR2) gene.
• The functional impact of these PROKR2 mutations on its signaling pathways remains unclear.

Purpose of the Study:

• To investigate the functional consequences of PROKR2 mutations on its G-protein and β-arrestin signaling pathways.
• To determine if PROKR2 mutations cause biased signaling.

Main Methods:

• HEK-293 cells were transfected with wild-type and mutant PROKR2.
• Activation of G-protein subtypes (Gq, Gs, Gi/o) and β-arrestin recruitment were measured upon ligand stimulation.
• Nine PROKR2 mutations were analyzed for their effects on signaling.

Main Results:

• Wild-type PROKR2 activates Gq, Gs, Gi/o proteins and recruits β-arrestins.
• Four mutations (R85C, R85H, R164Q, V331M) impaired Gq signaling but retained β-arrestin recruitment, indicating biased signaling.
• The R80C mutation affected β-arrestin recruitment but not G-protein activation.
• The R268C mutation showed impaired Gi/o signaling but retained Gq/Gs activation and β-arrestin recruitment.

Conclusions:

• PROKR2 mutations can differentially affect its signaling pathways, leading to biased signaling.
• This biased signaling may contribute to the pathogenesis of Kallmann syndrome or confer protective effects.