This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Court, D. A. Articles by Lill, R. Search for Related Content PubMed PubMed Citation Articles by Court, D. A. Articles by Lill, R.

 Previous Article  |  Next Article 

Mol. Cell. Biol., 08 1996, 4035-4042, Vol 16, No. 8
Copyright © 1996, American Society for Microbiology

Role of the intermembrane-space domain of the preprotein receptor Tom22 in protein import into mitochondria

DA Court, FE Nargang, H Steiner, RS Hodges, W Neupert and R Lill
Institut fur Physiologische Chemie, Physikalische Biochemie, Zellbiologie der Universitat Munchen, Munich, Germany.

Tom22 is an essential component of the protein translocation complex (Tom complex) of the mitochondrial outer membrane. The N-terminal domain of Tom22 functions as a preprotein receptor in cooperation with Tom20. The role of the C-terminal domain of Tom22, which is exposed to the intermembrane space (IMS), in its own assembly into the Tom complex and in the import of other preproteins was investigated. The C-terminal domain of Tom22 is not essential for the targeting and assembly of this protein, as constructs lacking part or all of the IMS domain became imported into mitochondria and assembled into the Tom complex. Mutant strains of Neurospora expressing the truncated Tom22 proteins were generated by a novel procedure. These mutants displayed wild-type growth rates, in contrast to cells lacking Tom22, which are not viable. The import of proteins into the outer membrane and the IMS of isolated mutant mitochondria was not affected. Some but not all preproteins destined for the matrix and inner membrane were imported less efficiently. The reduced import was not due to impaired interaction of presequences with their specific binding site on the trans side of the outer membrane. Rather, the IMS domain of Tom22 appears to slightly enhance the efficiency of the transfer of these preproteins to the import machinery of the inner membrane.

This article has been cited by other articles:

• Sherman, E. L., Go, N. E., Nargang, F. E. (2005). Functions of the Small Proteins in the TOM Complex of Neurospora crasssa. Mol. Biol. Cell 16: 4172-4182 [Abstract] [Full Text]  
• Esaki, M., Shimizu, H., Ono, T., Yamamoto, H., Kanamori, T., Nishikawa, S.-i., Endo, T. (2004). Mitochondrial Protein Import: REQUIREMENT OF PRESEQUENCE ELEMENTS AND TOM COMPONENTS FOR PRECURSOR BINDING TO THE TOM COMPLEX. J. Biol. Chem. 279: 45701-45707 [Abstract] [Full Text]  
• Nakamura, Y., Suzuki, H., Sakaguchi, M., Mihara, K. (2004). Targeting and Assembly of Rat Mitochondrial Translocase of Outer Membrane 22 (TOM22) into the TOM Complex. J. Biol. Chem. 279: 21223-21232 [Abstract] [Full Text]  
• Endo, T., Yamamoto, H., Esaki, M. (2003). Functional cooperation and separation of translocators in protein import into mitochondria, the double-membrane bounded organelles. J. Cell Sci. 116: 3259-3267 [Abstract] [Full Text]  
• Yano, M., Hoogenraad, N., Terada, K., Mori, M. (2000). Identification and Functional Analysis of Human Tom22 for Protein Import into Mitochondria. Mol. Cell. Biol. 20: 7205-7213 [Abstract] [Full Text]  
• Vaskova, M., Bentley, A. M., Marshall, S., Reid, P., Thummel, C. S., Andres, A. J. (2000). Genetic Analysis of the Drosophila 63F Early Puff: Characterization of Mutations in E63-1 and maggie, a Putative Tom22. Genetics 156: 229-244 [Abstract] [Full Text]  
• Ahting, U., Thun, C., Hegerl, R., Typke, D., Nargang, F. E., Neupert, W., Nussberger, S. (1999). The Tom Core Complex: The General Protein Import Pore of the Outer Membrane of Mitochondria. JCB 147: 959-968 [Abstract] [Full Text]  
• Rapaport, D., Neupert, W. (1999). Biogenesis of Tom40, Core Component of the Tom Complex of Mitochondria. JCB 146: 321-332 [Abstract] [Full Text]  
• Kanamori, T., Nishikawa, S.-i., Nakai, M., Shin, I., Schultz, P. G., Endo, T. (1999). Uncoupling of transfer of the presequence and unfolding of the mature domain in precursor translocation across the mitochondrial outer membrane. Proc. Natl. Acad. Sci. USA 96: 3634-3639 [Abstract] [Full Text]  
• Cohen, I., Kohl, C., McGarry, J. D., Girard, J., Prip-Buus, C. (1998). The N-terminal Domain of Rat Liver Carnitine Palmitoyltransferase 1 Mediates Import into the Outer Mitochondrial Membrane and Is Essential for Activity and Malonyl-CoA Sensitivity. J. Biol. Chem. 273: 29896-29904 [Abstract] [Full Text]  
• Dekker, P. J. T., Ryan, M. T., Brix, J., Müller, H., Hönlinger, A., Pfanner, N. (1998). Preprotein Translocase of the Outer Mitochondrial Membrane: Molecular Dissection and Assembly of the General Import Pore Complex. Mol. Cell. Biol. 18: 6515-6524 [Abstract] [Full Text]  
• Rodriguez-Cousino, N., Nargang, F. E., Baardman, R., Neupert, W., Lill, R., Court, D. A. (1998). An Import Signal in the Cytosolic Domain of the Neurospora Mitochondrial Outer Membrane Protein TOM22. J. Biol. Chem. 273: 11527-11532 [Abstract] [Full Text]  
• Saeki, K., Suzuki, H., Tsuneoka, M., Maeda, M., Iwamoto, R., Hasuwa, H., Shida, S., Takahashi, T., Sakaguchi, M., Endo, T., Miura, Y., Mekada, E., Mihara, K. (2000). Identification of Mammalian TOM22 as a Subunit of the Preprotein Translocase of the Mitochondrial Outer Membrane. J. Biol. Chem. 275: 31996-32002 [Abstract] [Full Text]  
• Dembowski, M., Kunkele, K.-P., Nargang, F. E., Neupert, W., Rapaport, D. (2001). Assembly of Tom6 and Tom7 into the TOM Core Complex of Neurospora crassa. J. Biol. Chem. 276: 17679-17685 [Abstract] [Full Text]