The mitochondrial morphology protein Mdm10 functions in assembly of the preprotein translocase of the outer membrane.
The biogenesis of mitochondrial outer membrane proteins involves the general translocase of the outer membrane (TOM complex) and the sorting and assembly machinery (SAM complex). The two known subunits of the SAM complex, Mas37 and Sam50, are required for assembly of the abundant outer membrane proteins porin and Tom40. We have identified an unexpected subunit of the SAM complex, Mdm10, which is involved in maintenance of mitochondrial morphology. Mitochondria lacking Mdm10 are selectively impaired in the final steps of the assembly pathway of Tom40, including the association of Tom40 with the receptor Tom22 and small Tom proteins, while the biogenesis of porin is not affected. Yeast mutants of TOM40, MAS37, and SAM50 also show aberrant mitochondrial morphology. We conclude that Mdm10 plays a specific role in the biogenesis of the TOM complex, indicating a connection between the mitochondrial protein assembly apparatus and the machinery for maintenance of mitochondrial morphology.
Meisinger
Chris
C
Institut für Biochemie und Molekularbiologie, Universität Freiburg, Hermann-Herder-Strasse 7, D-79104 Freiburg, Germany.
Rissler
Michael
M
Chacinska
Agnieszka
A
Szklarz
Luiza K Sanjuán
LK
Milenkovic
Dusanka
D
Kozjak
Vera
V
Schönfisch
Birgit
B
Lohaus
Christiane
C
Meyer
Helmut E
HE
Yaffe
Michael P
MP
Guiard
Bernard
B
Wiedemann
Nils
N
Pfanner
Nikolaus
N
D002478:Cells, Cultured; D007425:Intracellular Membranes / Q000201:enzymology / Q000378:metabolism* / Q000648:ultrastructure; D046911:Macromolecular Substances; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism* / Q000473:pathology / Q000648:ultrastructure; D033681:Mitochondrial Membrane Transport Proteins / Q000096:biosynthesis* / Q000235:genetics; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D021381:Protein Transport / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000378:metabolism* / Q000648:ultrastructure; D029701:Saccharomyces cerevisiae Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*
C089419:MDM10 protein, S cerevisiae; D046911:Macromolecular Substances; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D033681:Mitochondrial Membrane Transport Proteins; D024101:Mitochondrial Proteins; C092812:SAM37 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C487333:Sam50 protein, S cerevisiae; C090857:TOM22 protein, S cerevisiae; C066555:Tom40 protein, S cerevisiae