The Tim54p-Tim22p complex mediates insertion of proteins into the mitochondrial inner membrane

Oliver Kerscher, Jason Holder, Maithreyan Srinivasan, Roxanne S. Leung, Robert E. Jensen

Research output: Contribution to journalArticle

Abstract

We have identified a new protein, Tim54p, located in the yeast mitochondrial inner membrane. Tim54p is an essential import component, required for the insertion of at least two polytopic proteins into the inner membrane, but not for the translocation of precursors into the matrix. Several observations suggest that Tim54p and Tim22p are part of a protein complex in the inner membrane distinct from the previously characterized Tim23p-Tim17p complex. First, multiple copies of the TIM22 gene, but not TIM23 or TIM17, suppress the growth defect of a tim54-1 temperature- sensitive mutant. Second, Tim22p can be coprecipitated with Tim54p from detergent-solubilized mitochondria, but Tim54p and Tim22p do not interact with either Tim23p or Tim17p. Finally, the tim54-1 mutation destabilizes the Tim22 protein, but not Tim23p or Tim17p. Our results support the idea that the mitochondrial inner membrane carries two independent import complexes: one required for the translocation of proteins across the inner membrane (Tim23p-Tim17p), and the other required for the insertion of proteins into the inner membrane (Tim54p-Tim22p).

Original languageEnglish (US)
Pages (from-to)1663-1675
Number of pages13
JournalJournal of Cell Biology
Volume139
Issue number7
DOIs
StatePublished - Dec 29 1997

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Mitochondrial Membranes
Membranes
Proteins
Protein Transport
Detergents
Mitochondria
Yeasts
Mutation
Temperature
Growth
Genes

ASJC Scopus subject areas

  • Cell Biology

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The Tim54p-Tim22p complex mediates insertion of proteins into the mitochondrial inner membrane. / Kerscher, Oliver; Holder, Jason; Srinivasan, Maithreyan; Leung, Roxanne S.; Jensen, Robert E.

In: Journal of Cell Biology, Vol. 139, No. 7, 29.12.1997, p. 1663-1675.

Research output: Contribution to journalArticle

Kerscher, O, Holder, J, Srinivasan, M, Leung, RS & Jensen, RE 1997, 'The Tim54p-Tim22p complex mediates insertion of proteins into the mitochondrial inner membrane', Journal of Cell Biology, vol. 139, no. 7, pp. 1663-1675. https://doi.org/10.1083/jcb.139.7.1663
Kerscher, Oliver ; Holder, Jason ; Srinivasan, Maithreyan ; Leung, Roxanne S. ; Jensen, Robert E. / The Tim54p-Tim22p complex mediates insertion of proteins into the mitochondrial inner membrane. In: Journal of Cell Biology. 1997 ; Vol. 139, No. 7. pp. 1663-1675.
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