Mba1, a novel component of the mitochondrial protein export machinery of the yeast Saccharomyces cerevisiae.
The biogenesis of mitochondria requires the integration of many proteins into the inner membrane from the matrix side. The inner membrane protein Oxa1 plays an important role in this process. We identified Mba1 as a second mitochondrial component that is required for efficient protein insertion. Like Oxa1, Mba1 specifically interacts both with mitochondrial translation products and with conservatively sorted, nuclear-encoded proteins during their integration into the inner membrane. Oxa1 and Mba1 overlap in function and substrate specificity, but both can act independently of each other. We conclude that Mba1 is part of the mitochondrial protein export machinery and represents the first component of a novel Oxa1-independent insertion pathway into the mitochondrial inner membrane.
Preuss
M
M
Insitute for Phyisiological Chemistry, Goethestrasse 33, 80336 Münich, Germany.
Leonhard
K
K
Hell
K
K
Stuart
R A
RA
Neupert
W
W
Herrmann
J M
JM
D002455:Cell Division; D002467:Cell Nucleus / Q000235:genetics; D004579:Electron Transport / Q000235:genetics; D003576:Electron Transport Complex IV / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D005816:Genetic Complementation Test; D007425:Intracellular Membranes / Q000737:chemistry / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008928:Mitochondria / Q000737:chemistry / Q000201:enzymology / Q000378:metabolism*; D024101:Mitochondrial Proteins; D009154:Mutation / Q000235:genetics; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D011233:Precipitin Tests; D011485:Protein Binding; D014176:Protein Biosynthesis; D021381:Protein Transport; D012441:Saccharomyces cerevisiae / Q000166:cytology* / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D013379:Substrate Specificity
D005656:Fungal Proteins; C100490:MBA1 protein, S cerevisiae; D008565:Membrane Proteins; D024101:Mitochondrial Proteins; D009687:Nuclear Proteins; C090858:OXA1 protein; D029701:Saccharomyces cerevisiae Proteins; D003576:Electron Transport Complex IV