The C-terminal domain of Fcj1 is required for formation of crista junctions and interacts with the TOB/SAM complex in mitochondria

Crista junctions (CJs) are tubular invaginations of the inner membrane of mitochondria that connect the inner boundary with the cristae membrane. These architectural elements are critical for mitochondrial function. The 
Crista junctions (CJs) are tubular invaginations of the inner membrane of mitochondria that connect the inner boundary with the cristae membrane. These architectural elements are critical for mitochondrial function. The yeast inner membrane protein Fcj1, called mitofilin in mammals, was reported to be preferentially located at CJs and crucial for their formation. Here we investigate the functional roles of individual domains of Fcj1. The most conserved part of Fcj1, the C-terminal domain, is essential for Fcj1 function. In its absence, formation of CJ is strongly impaired and irregular, and stacked cristae are present. This domain interacts with full-length Fcj1, suggesting a role in oligomer formation. It also interacts with Tob55 of the translocase of outer membrane β-barrel proteins (TOB)/sorting and assembly machinery (SAM) complex, which is required for the insertion of β-barrel proteins into the outer membrane. The association of the TOB/SAM complex with contact sites depends on the presence of Fcj1. The biogenesis of β-barrel proteins is not significantly affected in the absence of Fcj1. However, down-regulation of the TOB/SAM complex leads to altered cristae morphology and a moderate reduction in the number of CJs. We propose that the C-terminal domain of Fcj1 is critical for the interaction of Fcj1 with the TOB/SAM complex and thereby for stabilizing CJs in close proximity to the outer membrane. These results assign novel functions to both the C-terminal domain of Fcj1 and the TOB/SAM complex.
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Metadaten
Author:Christian Körner, Miguel Barrera, Jovana Dukanovic, Katharina Eydt, Max Harner, Regina Rabl, Frank Vogel, Doron Rapaport, Walter Neupert, Andreas S. Reichert
URN:urn:nbn:de:hebis:30:3-251975
DOI:http://dx.doi.org/10.1091/mbc.E11-10-0831
ISSN:1939-4586
ISSN:1059-1524
Parent Title (English):Molecular biology of the cell
Publisher:American Society for Cell Biology
Place of publication:Bethesda, Md.
Document Type:Article
Language:English
Date of Publication (online):2012/04/11
Date of first Publication:2012/04/11
Publishing Institution:Univ.-Bibliothek Frankfurt am Main
Release Date:2012/06/13
Volume:23
Issue:11
Pagenumber:13
First Page:2143
Last Page:2155
Institutes:Biowissenschaften
Dewey Decimal Classification:570 Biowissenschaften; Biologie
Sammlungen:Universitätspublikationen
Sondersammelgebiets-Volltexte
Licence (German):License LogoCreative Commons - Namensnennung-Keine kommerzielle Nutzung-Weitergabe unter gleichen Bedingungen

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