Open AccessRemoval of a hydrophobic domain within the mature portion of a mitochondrial inner membrane protein causes its mislocalization to the matrix.
Author(s) -
Scott Glaser,
Brian Miller,
M G Cumsky
Publication year - 1990
Publication title -
molecular and cellular biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.14
H-Index - 327
eISSN - 1067-8824
pISSN - 0270-7306
DOI - 10.1128/mcb.10.5.1873
Subject(s) - protein subunit , biology , translocase of the inner membrane , inner mitochondrial membrane , protein targeting , inner membrane , cytochrome c oxidase , mitochondrion , mitochondrial matrix , biochemistry , mitochondrial carrier , microbiology and biotechnology , intermembrane space , membrane protein , cytosol , bacterial outer membrane , mitochondrial membrane transport protein , membrane , gene , enzyme , escherichia coli
We have examined the import and intramitochondrial localization of the precursor to yeast cytochrome c oxidase subunit Va, a protein of the mitochondrial inner membrane. The results of studies on the import of subunit Va derivatives carrying altered presequences suggest that the uptake of this protein is highly efficient. We found that a presequence of only 5 amino acids (Met-Leu-Ser-Leu-Arg) could direct the import and localization of subunit Va with wild-type efficiency, as judged by several different assays. We also found that subunit Va could be effectively targeted to the mitochondrial inner membrane with a heterologous presequence that failed to direct import of its cognate protein. The results presented here confirmed those of an earlier study and showed clearly that the information required to "sort" subunit Va to the inner membrane resides in the mature protein sequence, not within the presequence per se. We present additional evidence that the aforementioned sorting information is contained, at least in part, in a hydrophobic stretch of 22 amino acids residing within the C-terminal third of the protein. Removal of this domain caused subunit Va to be mislocalized to the mitochondrial matrix.