The receptor subunit Tom20 is dynamically associated with the TOM complex in mitochondria of human cells.

The outer membrane translocase (TOM) is the import channel for nuclear-encoded mitochondrial proteins. The general import pore contains Tom40, Tom22, Tom5, Tom6, and Tom7. Precursor proteins are bound by the (peripheral) receptor proteins Tom20, Tom22, and Tom70 before being imported by the TOM complex.