Arabidopsis heterotrimeric G protein β subunit interacts with a plasma membrane 2C-type protein phosphatase, PP2C52.

Heterotrimeric G proteins (Gα, Gβ, Gγ) play important roles in signal transduction among various eukaryotic species. G proteins transmit signals by regulating the activities of effector proteins, but only a few Gβ-interacting effectors have been identified in plants. Here we show by a yeast two-hybrid screen that a putative myristoylated 2C-type protein phosphatase, PP2C52, is an Arabidopsis Gβ (AGB1)-interacting partner. The interaction between AGB1 and PP2C52 was confirmed by an in vitro pull-down assay and a bimolecular fluorescence complementation assay. PP2C52 transcripts were detected in many tissues. PP2C52 was localized to the plasma membrane and a mutation in the putative myristoylation site of PP2C52 disrupted its plasma membrane localization. Our results suggest that PP2C52 interacts with AGB1 on the plasma membrane and transmits signals via dephosphorylation of other proteins.