Mdm10 is an ancient eukaryotic porin co-occurring with the ERMES complex

14.10.2013

Flinner N, Ellenrieder L, Stiller S, Becker T, Schleiff E, Mirus O

Biochim Biophys Acta. 2013;1833(12):3314-25

The beta-barrel protein Mdm10 of the mitochondrial outer membrane plays a crucial role in the biogenesis of mitochondria. Mdm10 is a central component of the ER-mitochondrial encounter structure (ERMES) that tethers the ER to mitochondria. Furthermore, it associates with the sorting and assembly machinery (SAM complex). The segregation between both protein machineries is regulated by binding of Tom7. The structural basis of Mdm10 for these interactions were unknown. Here we present a structural model of Mdm10 generated by homology modeling. Mdm10 belongs to the Tom40/VDAC protein family. In contrast to Tom40/VDAC it exposes large loops two both sites of the membrane. However, the loops are neither critical for the interactions to ERMES and SAM components nor for the function of Mdm10 of Saccharomyces cerevisiae. Finally, phylogenetic studies reveal that Mdm10 evolutionary appeared together with core components of the ERMES machinery supporting the view that Mdm10 is an central component of this ER-mitochondria tether.

BIOSS

Mdm10 is an ancient eukaryotic porin co-occurring with the ERMES complex