What are guanosine triphosphate-binding proteins doing in mitochondria?

The discovery of GTP-binding proteins in mitochondria is a recent event. These regulatory proteins may be participating in membrane fusion and thereby playing important roles in the physiology of the mitochondrion. So far, it has been proposed that GTP-binding protein mediated membrane fusion may be involved in protein import, steroid hormone production and mitochondrial amalgamation during spermatogenesis.