MAU-8 is a Phosducin-like Protein Required for G Protein Signaling in C. Elegans

The mau-8(qm57) mutation inhibits the function of GPB-2, a heterotrimeric G protein beta subunit, and profoundly affects behavior through the Galphaq/Galphao signaling network in C. elegans. mau-8 encodes a nematode Phosducin-like Protein (PhLP), and the qm57 mutation leads to the loss of a predicted phosphorylation site in the C-terminal domain of PhLP that binds the Gbetagamma surface implicated in membrane interactions. In developing embryos, MAU-8/PhLP localizes to the cortical region, concentrates at the centrosomes of mitotic cells and remains associated with the germline blastomere. In adult animals, MAU-8/PhLP is ubiquitously expressed in somatic tissues and germline cells. MAU-8/PhLP interacts with the PAR-5/14.3.3 protein and with the Gbeta subunit GPB-1. In mau-8 mutants, the disruption of MAU-8/PhLP stabilizes the association of GPB-1 with the microtubules of centrosomes. Our results indicate that MAU-8/PhLP modulates G protein signaling, stability and subcellular location to regulate various physiological functions, and they suggest that MAU-8 might not be limited to the Galphaq/Galphao network.