Functional and Physical Interactions of Components of the Yeast Mitochondrial Inner‐Membrane Import Machinery (MIM)

Abstract

The essential mitochondrial inner‐membrane protein, Mim44, is involved in the translocation of pre‐proteins across the mitochondrial inner membrane. Two other putative components of this protein‐translocation system are the integral inner‐membrane proteins, Mim23 and Mim17. Here, we present genetic evidence for functional co‐operation of all three proteins. Furthermore, we show that Mim23 and Mim17 are associated in a protein complex that also contains two proteins of 55 kDa and 20 kDa. We speculate that this subcomplex forms the proteinaceous import channel of the inner‐membrane which transiently interacts with a less abundant peripheral complex of Mim44 and mitochondrial heat‐shock protein Hsp70. Copyright © 1995, Wiley Blackwell. All rights reserved