Probably acts as a GEF (guanine nucleotide exchange factor) for the Rho family of small GTP-binding proteins (G proteins) that stimulates the dissociation of GDP to enable subsequent binding of GTP (By similarity). May also chaperone the processing and/or trafficking of small GTPases independently of GEF activity (By similarity). By interacting with Miro, promotes mitochondrial fission in response to high calcium concentrations (PubMed:27716788). Interacts with Miro. Expressed in the mesoderm during embryogenesis. RNAi-mediated knockdown perturbs mitochondrial distribution and dynamics. Truncated N-terminus.