Regulator of mitochondrial fusion: acts by forming homo- and heterodimers at the mitochondrial outer membrane and facilitating the formation of PLD6/MitoPLD dimers. May act by regulating phospholipid metabolism via PLD6/MitoPLD. Homodimer and heterodimer; forms heterodimers with MIGA1. Interacts with PLD6/MitoPLD. Belongs to the mitoguardin family.