Biogenesis of mitochondria: Dual role of Tom7 in modulating assembly of the preprotein translocase of the outer membrane

Abstract

Biogenesis of the translocase of the outer mitochondrial membrane (TOM complex) involves the assembly of the central β-barrel forming protein Tom40 with six different subunits that are embedded in the membrane via α-helical transmembrane segments. The sorting and assembly machinery (SAM complex) of the outer membrane plays a central role in this process. The SAM complex mediates the membrane integration of β-barrel precursor proteins including Tom40. The small Tom proteins Tom5 and Tom6 associate with the precursor of Tom40 at the SAM complex at an early stage of the assembly process and play a stimulatory role in the formation of the mature TOM complex. A fraction of the SAM components inte..