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Dynamic interaction of the protein translocation systems in the inner and outer membranes of yeast mitochondria.
Author(s) -
Horst M.,
HilfikerRothenfluh S.,
Oppliger W.,
Schatz G.
Publication year - 1995
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1995.tb07223.x
Subject(s) - biology , yeast , chromosomal translocation , mitochondrion , membrane , saccharomyces cerevisiae , translocase of the inner membrane , inner membrane , bacterial outer membrane , microbiology and biotechnology , biophysics , inner mitochondrial membrane , biochemistry , mitochondrial membrane transport protein , gene , escherichia coli
Mitochondria contain two distinct protein import systems, one in the outer and the other in the inner membrane. These systems can act independently of one another in submitochondrial fractions of if a protein is transported to the outer membrane or to the intermembrane space. It has been proposed that the two systems associate reversibly when a protein is transported across both membranes, but this hypothesis has remained unproven. In order to address this question, we have checked whether antibodies against a subunit of one system can co‐immunoprecipitate subunits of the other system. We find that the two systems associate stably if a matrix‐targeted precursor is arrested during import; no association is seen in the absence of a stuck precursor. These experiments provide direct evidence that protein import into the mitochondrial matrix is mediated by the reversible interaction of the two translocation systems.