Skip Navigation


Journal of Biochemistry Advance Access originally published online on April 16, 2007
Journal of Biochemistry 2007 141(6):897-906; doi:10.1093/jb/mvm097
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow All Versions of this Article:
141/6/897    most recent
mvm097v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrow Request Permissions
Google Scholar
Right arrow Articles by Kinoshita, J.-y.
Right arrow Articles by Oka, T.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Kinoshita, J.-y.
Right arrow Articles by Oka, T.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

© 2007 The Japanese Biochemical Society.

Identification and Characterization of a New Tom40 Isoform, a Central Component of Mitochondrial Outer Membrane Translocase

Jun-ya Kinoshita, Katsuyoshi Mihara* and Toshihiko Oka

Department of Molecular Biology, Graduate School of Medical Science, Kyushu University, Fukuoka 812-8582, Japan

*To whom correspondence should be addressed. Tel: +81 92 642 6176, Fax: +81 92 642 6183, E-mail: mihara{at}cell.med.kyushu-u.ac.jp

Received January 9, 2007; Accepted April 8, 2007


  Abstract

Newly synthesized precursors are transported into mitochondria through an outer membrane translocase, TOM. Tom40, a central pore-forming component, interacts directly with precursors to help them translocate across the outer membrane. We identified a new isoform of rat Tom40, Tom40B, which is conserved among mammals and exhibits significant similarities to Tom40 in other eukaryotes. Tom40B is an integral protein localized on the mitochondrial outer membrane, and expressed widely in all tissues examined except testis. Deletion mutant analysis revealed that the 28 amino acid residues at the carboxyl terminus were crucial for the mitochondrial targeting of Tom40B. Tom40B co-precipitated with other Tom components and formed a large protein complex. Furthermore, Tom40B directly bound to precursors of the matrix-targeted proteins with high affinities, comparable to those of Tom40A, a previously identified isoform. These findings indicate that Tom40B is a functional component of mitochondrial outer membrane translocase.

Key Words: mitochondria, mitochondrial targeting sequence, presequence binding, TOM complex, Tom40 isoform

Abbreviations: BN, blue native; ER, endoplasmic reticulum; HA, hemmagglutinin; MPP, mitochondrial processing peptidase; PBS, phosphate buffered saline; RT-PCR, malate dehydrogenase; SCC, side chain cleavage; SDS–PAGE, sodium dodecyl sulphate–polyacrylamide gel electrophoresis; SPR, Surface Plasmon Resonance; TOM, translocase of the outer membrane


Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?




Disclaimer: Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.