Regulation of Chemokine Signal Integration by Activator of G-Protein Signaling 4 (AGS4).

ABSTRACT: Activator of G-protein signaling 4 (AGS4)/G-protein signaling modulator 3 (Gpsm3) contains three G-protein regulatory (GPR) motifs, each of which can bind G?i-GDP free of G?? We previously demonstrated that the AGS4-G?i interaction is regulated by seven transmembrane-spanning receptors (7-TMR), which may reflect direct coupling of the GPR-G?i module to the receptor analogous to canonical G??? heterotrimer. We have demonstrated that the AGS4-G?i complex is regulated by chemokine receptors in an agonist-dependent manner that is receptor-proximal. As an initial approach to investigate the functional role(s) of this regulated interaction in vivo, we analyzed leukocytes, in which AGS4/Gpsm3 is predominantly expressed, from AGS4/Gpsm3-null mice. Loss of AGS4/Gpsm3 resulted in mild but significant neutropenia and leukocytosis. Dendritic cells, T lymphocytes, and neutrophils from AGS4/Gpsm3-null mice also exhibited significant defects in chemoattractant-directed chemotaxis and extracellular signal-regulated kinase activation. An in vivo peritonitis model revealed a dramatic reduction in the ability of AGS4/Gpsm3-null neutrophils to migrate to primary sites of inflammation. Taken together, these data suggest that AGS4/Gpsm3 is required for proper chemokine signal processing in leukocytes and provide further evidence for the importance of the GPR-G?i module in the regulation of leukocyte function.

SUBMITTER: Robichaux WG 

PROVIDER: S-EPMC5325072 | biostudies-other | 2017 Mar

REPOSITORIES: biostudies-other