Adds a GMP to the 5'-end of tRNA(His) after transcription and RNase P cleavage. This step is essential for proper recognition of the tRNA and for the fidelity of protein synthesis (Probable). Also functions as a guanyl-nucleotide exchange factor/GEF for the MFN1 and MFN2 mitofusins thereby regulating mitochondrial fusion (, ). By regulating both mitochondrial dynamics and bioenergetic function, it contributes to cell survival following oxidative stress (, ).
Subcellular locations: Cytoplasm, Mitochondrion outer membrane
Expressed in many tissues.