Back to basics: A revealing secondary reduction of the mitochondrial protein import pathway in diverse intracellular parasites

► All mitosomes contain a highly reduced protein import machinery. ► The TOM, SAM, and TIM22/23 complexes are reduced to only one or two proteins. ► One TIM complex can carry out import through and insertion into the inner membrane. ► Different parasites retained similar protein components of the import machinery. ► This suggests a model for the nascent import machinery in the first eukaryotes.