The heretotrimeric G protein subunit Gαi is present on mitochondria

Receptors that signal through heretotrimeric GTP binding (G) proteins mediate the majority of intercellular communication. Recent evidence suggests that receptors acting through G proteins also transfer signals across the nuclear membrane. Here we present cell fractionation and immunolabeling data showing that the heretotrimeric G protein subunit Gαi is associated with mitochondria. This finding suggests that G protein receptor signaling may be a feature common to all membranes.