Mitochondrial GTPase involved in mitochondrial trafficking. Probably involved in control of anterograde transport of mitochondria and their subcellular distribution. Promotes mitochondrial fission during high calcium conditions (By similarity). Interacts with the kinesin-binding proteins TRAK1/OIP106 and TRAK2/GRIF1, forming a link between mitochondria and the trafficking apparatus of the microtubules (By similarity). Interacts with RAP1GDS1 (By similarity). Interacts with ARMCX1 (PubMed:28009275). Found in a complex with KIF5B, OGT, RHOT2 and TRAK1 (By similarity). Colocalizes with MGARP and RHOT2 at the mitochondria. Ubiquitinated by PRKN during mitophagy, leading to its degradation and enhancement of mitophagy. Deubiquitinated by USP30 (By similarity). Belongs to the mitochondrial Rho GTPase family.