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The yeast deubiquitinating enzyme Ubp16 is anchored to the outer mitochondrial membrane
Author(s) -
Kinner Andrea,
Kölling Ralf
Publication year - 2003
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(03)00801-9
Subject(s) - deubiquitinating enzyme , translocase of the inner membrane , mitochondrion , biology , mitochondrial carrier , microbiology and biotechnology , integral membrane protein , inner mitochondrial membrane , ubiquitin , bacterial outer membrane , cell fractionation , vesicle associated membrane protein 8 , membrane protein , biochemistry , mitochondrial membrane transport protein , membrane , escherichia coli , gene
We looked for membrane‐associated Dubs (deubiquitinating enzymes) among the 16 yeast members of the ubiquitin‐specific processing protease (Ubp) family to identify potential regulators of ubiquitin‐dependent processes at membranes. For each of the Ubps examined, a certain fraction was found to be membrane associated. This fraction was only small for most Ubps but quite substantial for some Ubps. For Ubp4/Doa4 almost 40% of the protein was found in the membrane fraction suggesting that this protein performs a major function at membranes, probably at endosomes. Among the proteins tested, only one protein (Ubp16) was exclusively membrane associated. By cell fractionation and immunofluorescence experiments, we could show that Ubp16 is localized to mitochondria. Ubp16 contains an N‐terminal hydrophobic domain that is similar to N‐terminal sequences of other yeast outer mitochondrial membrane proteins. The presence of this putative signal sequence and the result of protease protection experiments suggest that Ubp16 is an integral membrane protein of the outer mitochondrial membrane with an N in –C out orientation. Phenotypic characterization of the Δ ubp16 mutant and overexpression studies further suggest that Ubp16 is probably not important for the general functioning of mitochondria, but that it rather performs a more specialized function at mitochondria.