JCB logo
MBL International Tel: 800.200.5459 CLICK HERE
  Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents

Published 13 October 2003. doi:10.1083/jcb.200305051
This Article
Right arrow Full Text
Right arrow PDF (Full Text)
Right arrow PPT slides of all figures
Right arrow Alert me when this article is cited
Right arrow Citation Map
Services
Right arrow Email this article
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new content in the JCB
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via CrossRef
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Yano, M.
Right arrow Articles by Mori, M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Yano, M.
Right arrow Articles by Mori, M.
Social Bookmarking
 Add to CiteULike   Add to Complore   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Reddit   Add to Technorati  
What's this?
© The Rockefeller University Press, 0021-9525/2003/10/45 $8.00
The Journal of Cell Biology, Volume 163, Number 1, 45-56


Article

AIP is a mitochondrial import mediator that binds to both import receptor Tom20 and preproteins

Masato Yano, Kazutoyo Terada and Masataka Mori

Department of Molecular Genetics, Graduate School of Medical Sciences, Kumamoto University, Kumamoto 860-8556, Japan

Address correspondence to Masato Yano, Department of Molecular Genetics, Graduate School of Medical Sciences, Kumamoto University, Honjo 1-1-1, Kumamoto 860-8556, Japan. Tel.: 81-96-373-5140. Fax: 81-96-373-5145. email: myano{at}gpo.kumamoto-u.ac.jp; or Masataka Mori, Department of Molecular Genetics, Graduate School of Medical Sciences, Kumamoto University, Honjo 1-1-1, Kumamoto 860-8556, Japan. Tel.: 81-96-373-5140. Fax: 81-96-373-5145. email: masa{at}gpo.kumamoto-u.ac.jp

Most mitochondrial preproteins are maintained in a loosely folded import-competent conformation by cytosolic chaperones, and are imported into mitochondria by translocator complexes containing a preprotein receptor, termed translocase of the outer membrane of mitochondria (Tom) 20. Using two-hybrid screening, we identified arylhydrocarbon receptor–interacting protein (AIP), an FK506-binding protein homologue, interacting with Tom20. The extreme COOH-terminal acidic segment of Tom20 was required for interaction with tetratricopeptide repeats of AIP. An in vitro import assay indicated that AIP prevents preornithine transcarbamylase from the loss of import competency. In cultured cells, overexpression of AIP enhanced preornithine transcarbamylase import, and depletion of AIP by RNA interference impaired the import. An in vitro binding assay revealed that AIP specifically binds to mitochondrial preproteins. Formation of a ternary complex of Tom20, AIP, and preprotein was observed. Hsc70 was also found to bind to AIP. An aggregation suppression assay indicated that AIP has a chaperone-like activity to prevent substrate proteins from aggregation. These results suggest that AIP functions as a cytosolic factor that mediates preprotein import into mitochondria.

Key Words: chaperone; import competency; protein targeting; mitochondria; Tom20


Abbreviations used in this paper: AhR, arylhydrocarbon receptor; AIP, arylhydrocarbon receptor–interacting protein; ECHS1, enoyl-coenzyme A hydratase 1 precursor; FKBP52, 52-kD FK506-binding protein; hTom20, human Tom20; MBP, maltose-binding protein; NDUFB10, NADH:ubiquinone oxidoreductase 1ß subcomplex 10; OTC, ornithine transcarbamylase; pOTC, preornithine transcarbamylase; PPIase, peptidyl-prolyl cis/trans isomerase; siRNA, small interfering RNA; Tom, translocase of the outer membrane of mitochondria; TPR, tetratricopeptide repeat.


Add to CiteULike CiteULike   Add to Complore Complore   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us   Add to Digg Digg   Add to Reddit Reddit   Add to Technorati Technorati    What's this?


This article has been cited by other articles:



  Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents