Mas37p, a novel receptor subunit for protein import into mitochondria

Sabine Gratzer, Trevor Lithgow, Ronald E. Bauer, Erwin Lamping, Fritz Paltauf, Sepp D. Kohlwein, Volker Haucke, Tina Junne, Gottfried Schatz, Martin Horst

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By screening a collection of Saccharomyces cerevisiae mutants temperature sensitive for growth on a nonfermentable carbon source, we have isolated a gene (termed MAS37) which encodes a novel receptor for protein import into mitochondria. Mas37p is a 37-kD outer membrane protein with two putative membrane-spanning regions. Inactivation of the MAS37 gene renders cells temperature-sensitive for respiration-driven growth, inhibits import of precursors into isolated mitochondria, and is synthetically lethal with a deletion of one of the genes encoding the import receptors Mas70p or Mas20p. Inactivation of Mas37p with specific antibodies inhibits import of different precursors to different extents; the precursor specificity of Mas37p resembles that of the previously described import receptor Mas70p. Mas70p and Mas37p form a 1:1 complex in detergent extracts of mitochondria and overexpression of one protein enhances that of the other. We suggest that the Mas37p/Mas70p heterodimer functions as a receptor for protein import into yeast mitochondria and that the mitochondrial receptor system consists of hetero-oligomeric subcomplexes with distinct binding activities, but overlapping precursor specificities.

Original languageEnglish
Pages (from-to)25-34
Number of pages10
JournalJournal of Cell Biology
Issue number1
Publication statusPublished - 1 Apr 1995
Externally publishedYes

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