The GTPase domain of Galphao contributes to the functional interaction of Galphao with the promyelocytic leukemia zinc finger protein.

Go, one of the most abundant heterotrimeric G proteins in the brain, is classified as a member of the Gi/Go family based on its homology to Gi proteins. Recently, we identified promyelocytic leukemia zinc finger protein (PLZF) as a candidate downstream effector for the alpha subunit of Go (Galphao). Activated Galphao interacts with PLZF and augments its function as a repressor of transcription and cell growth. G protein-coupled receptor-mediated Galphao activation also enhanced PLZF function. In this study, we determined that the GTPase domain of Galphao contributes to Galphao:PLZF interaction. We also showed that the Galphao GTPase domain is important in modulating the function of PLZF. This data indicates that the GTPase domain of Galphao may be necessary for the functional interaction of Galphao with PLZF.