The translocase of the outer membrane (TOM) complex is a heteromeric assembly that spans the mitochondrial outer membrane. The TOM complex mediates the transit nascent precursor proteins from cytosolic ribosomes across the outer mitochondrial membrane. The translocated proteins may be transferring them to the translocases of the inner membrane (TIM) complex, for transfer to mitochondrial matrix or insertion into the inner membrane, or to the sorting and assembly machinery (SAM) complex for insertion into the outer membrane, or be released into the intermembrane space. The TOM complex is formed from 7 core proteins: Tom40 forms a β-barrel protein-conducting channel, Tom20, Tom70, Tom22 are preprotein receptors and Tom5, Tom6, Tom7 are involved with complex stability and assembly. (Adapted from PMID:33083003.)