As inferred from the yeast SAM50 complex, the human SAMM50 Complex (SAM50 complex, TOB55 complex) inserts mainly beta-barrel proteins into the outer membrane after they have passed from the cytosol, through the TOMM40:TOMM70 complex, and into the intermembrane space.
In yeast, experimentally verified substrates of the SAM50 complex include TOM40 (TOMM40 in human), MDM10, Porin1 (VDAC1 in human), and TOM22 (TOMM22 in human). In humans, TOMM40 (Humphries et al. 2005) and VDAC1 (Kozjak-Pavlovic et al. 2007, homologous to yeast Porin1) have been shown to be substrates. Many other mitochondrial proteins are anticipated to be substrates of the SAMM50 complex.