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P 22 - Dr. Thomas Becker
The protein sorting and assembly machinery of the mitochondrial outer membrane
 | Dr. Thomas Becker Institut für Biochemie und Molekularbologie, Universität Freiburg Stefan-Meier-Str. 17 79104 Freiburg Phone: +49 761 203-5243 Fax: +49 761 203-5261 |
Project Summary
The proteins of the mitochondrial outer membrane are embedded into the membrane by α-helical or β-barrel domains. The proteins are synthesized as precursors on cytosolic ribosomes and sorted into the target membrane by specific protein complexes. The sorting and assembly machinery (SAM) mediates the insertion of β-barrel precursors, whereas the mitochondrial import (MIM) complex is crucial for the biogenesis of several outer membrane proteins with α-helical transmembrane segments. We have discovered that both protein sorting machineries form a dynamic network to mediate biogenesis of outer membrane proteins. By coupling to different interaction partners the SAM complex facilitates the assembly of β-barrel proteins with α-helical membrane proteins. The MIM complex cooperates with several protein translocases to promote membrane integration and assembly of different types of client proteins. The goal of this project is to characterize the mode of coupling of SAM and MIM complexes to binding partners. We will analyze how precursor proteins are delivered to SAM or MIM and map the molecular environment of precursor proteins bound to the different SAM and MIM complexes. We will test our hypothesis that the functional specificity of the two protein sorting machineries is altered by coupling to different outer membrane proteins to mediate the biogenesis of different classes of substrate proteins. | |