Molecular and General Genetics MGG

, Volume 263, Issue 3, pp 527–534

Functional specificity of the mitochondrial DnaJ protein, Mdj1p, in Saccharomyces cerevisiae

  • T. Lisse
  • E. Schwarz

DOI: 10.1007/s004380051198

Cite this article as:
Lisse, T. & Schwarz, E. Mol Gen Genet (2000) 263: 527. doi:10.1007/s004380051198


Inactivation of the gene for the mitochondrial DnaJ homolog, Mdj1p, in Saccharomyces cerevisiae results in temperature sensitivity and the loss of respiratory activity; the latter phenotype has been attributed to the loss of mitochondrial DNA. To investigate the functional specificity of Mdj1p, non-mitochondrial DnaJ proteins were targeted to mitochondria and tested for their ability to substitute for Mdj1p. The tested DnaJ proteins were able to complement the two Mdj1p-linked phenotypes, i.e., respiratory activity and growth at 37 °C, to different extents, ranging from full to very poor complementation. All DnaJ homologs ensured faithful propagation of the mitochondrial genome. N-terminal fragments of Mdj1p and Escherichia coli DnaJ comprising the well-characterized J domain partially substituted for Mdj1p. As the only hitherto known function of the N-terminal fragment is modulation of the substrate binding activity of the cognate Hsp70, we conclude that both Mdj1p-linked phenotypes – maintenance of respiratory activity and the ability to grow at elevated temperature – involve a mitochondrial Hsp70 partner protein.

Key words Mitochondrial DnaJMdj1pMitochondrial DNAComplementationChaperone

Copyright information

© Springer-Verlag Berlin Heidelberg 2000

Authors and Affiliations

  • T. Lisse
    • 1
  • E. Schwarz
    • 1
  1. 1.Institut für Biotechnologie, Martin-Luther-Universität Halle-Wittenberg, Kurt-Mothes-Str. 3, 06120 Halle, Germany E-mail:, Tel.: + 49-345-5524856; Fax: + 49-345-5527013DE