Import and orientation of the MWFE protein in mitochondrial NADH-ubiquinone oxidoreductase.
The MWFE subunit of the mitochondrial NADH-ubiquinone oxidoreductase (complex I) is a small, essential membrane protein of 70 amino acids that is made in the cytosol, imported into mitochondria, and assembled without further proteolytic processing. The experiments identify the first approximately 30 amino acids as a minimal mitochondrial targeting sequence, and establish its orientation in the inner membrane and in complex I. This sequence has a highly conserved glutamate at position 4, which is not typical of a mitochondrial targeting signal. However, it is not essential for MWFE function. Within this sequence there is also a 'stop-transfer' signal. The membrane anchor cannot be replaced by that from another subunit within complex I.
Yadava
Nagendra
N
Section of Molecular Biology, Division of Biological Sciences, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA 92093-0322, USA.
Scheffler
Immo E
IE