Dislocation by the m-AAA protease increases the threshold hydrophobicity for retention of transmembrane helices in the inner membrane of yeast mitochondria
2012 (English)Manuscript (preprint) (Other academic)
Sorting of mitochondrial inner membraneproteins is a complex process where transloconsand proteases function in a concerted way.Many inner membrane proteins insert into themembrane via the TIM23 translocon and someare then further acted upon by themitochondrial m-AAA protease, a molecularmotor capable of dislocating proteins from theinner membrane. This raises the possibility thatthe threshold hydrophobicity for the retentionof transmembrane segments in the innermembrane is different, depending on whetherthey belong to membrane proteins that are m-AAA protease substrate or not. Here, usingmodel transmembrane segments engineeredinto m-AAA protease-dependent proteins, weshow that the threshold hydrophobicity formembrane retention measured in yeast cells inthe absence of a functional m-AAA protease ismarkedly lower than that measured in itspresence. Whether a given hydrophobicsegment in a mitochondrial inner membraneprotein will ultimately form a transmembranehelix may therefore depend on whether or not,during biogenesis, it will be exposed to thepulling force exerted by the m-AAA protease.
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IdentifiersURN: urn:nbn:se:su:diva-83481OAI: oai:DiVA.org:su-83481DiVA: diva2:575961