Sequential processing of a mitochondrial tandem protein: Insights into protein import in Schizosaccharomyces pombe

Oleh Khalimonchuk, Martin Ott, Soledad Funes, Kai Ostermann, Gerhard Rödel, Johannes M. Herrmann

Research output: Contribution to journalArticle

14 Scopus citations

Abstract

The sequencing of the genome of Schizosaccharomyces pombe revealed the presence of a number of genes encoding tandem proteins, some of which are mitochondrial components. One of these proteins (pre-Rsm22-Cox11) consists of a fusion of Rsm22, a component of the mitochondrial ribosome, and Cox11, a factor required for copper insertion into cytochrome oxidase. Since in Saccharomyces cerevisiae, Cox11 is physically attached to the mitochondrial ribosome, it was suggested that the tandem organization of Rsm22-Cox11 is used to covalently tie the mitochondrial ribosome to Cox11 in S. pombe. We report here that pre-Rsm22-Cox11 is matured in two subsequent processing events. First, the mitochondrial presequence is removed. At a later stage of the import process, the Rsm22 and Cox11 domains are separated by cleavage of the mitochondrial processing peptidase at an internal processing site. In vivo data obtained using a tagged version of pre-Rsm22-Cox11 confirmed the proteolytic separation of Cox11 from the Rsm22 domain. Hence, the tandem organization of pre-Rsm22-Cox11 does not give rise to a persistent fusion protein but rather might be used to increase the import efficiency of Cox11 and/or to coordinate expression levels of Rsm22 and Cox11 in S. pombe.

Original languageEnglish (US)
Pages (from-to)997-1006
Number of pages10
JournalEukaryotic Cell
Volume5
Issue number7
DOIs
StatePublished - Jul 2006

ASJC Scopus subject areas

  • Microbiology
  • Molecular Biology

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