Internal targeting signal of the BCS1 protein: A novel mechanism of import into mitochondria

Heike Fölsch*, Bernard Guiard, Walter Neupert, Rosemary A. Stuart

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

155 Scopus citations


The BCS1 protein is anchored in the mitochondrial inner membrane via a single transmembrane domain and has an N(out)-C(in) topology. Unlike the majority of nuclear encoded mitochondrial preproteins, the BCS1 protein does not contain an N-terminal targeting sequence. A positively charged segment of amino acids which is located immediately C-terminal to the transmembrane domain acts as an internal targeting signal. In order to function, we postulate that this sequence co-operates with the transmembrane domain to form a tight hairpin loop structure. This loop is translocated across the inner membrane via the MIM/mt-Hsp70 machinery in a membrane potential-dependent manner. This novel mechanism of import and sorting of the BCS1 protein is proposed to represent a more general mechanism used by a number of inner membrane proteins.

Original languageEnglish (US)
Pages (from-to)479-487
Number of pages9
JournalEMBO Journal
Issue number3
StatePublished - Feb 1 1996


  • BCS1
  • Inner membrane proteins
  • Membrane insertion
  • Mitochondrial targeting signals
  • Saccharomyces cerevisiae

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Immunology and Microbiology(all)
  • Molecular Biology
  • Neuroscience(all)


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