Mas37p, a novel receptor subunit for protein import into mitochondria.
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.
Gratzer
S
S
Biozentrum, University of Basel, Switzerland.
Lithgow
T
T
Bauer
R E
RE
Lamping
E
E
Paltauf
F
F
Kohlwein
S D
SD
Haucke
V
V
Junne
T
T
Schatz
G
G
Horst
M
M
D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D003600:Cytosol / Q000378:metabolism; D015870:Gene Expression; D005800:Genes, Fungal; D046911:Macromolecular Substances; D008565:Membrane Proteins / Q000096:biosynthesis* / Q000737:chemistry / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism*; D008961:Models, Structural; D008969:Molecular Sequence Data; D009154:Mutation; D011487:Protein Conformation; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D013431:Sulfates / Q000378:metabolism; D013462:Sulfur Radioisotopes; D013696:Temperature
D046911:Macromolecular Substances; D008565:Membrane Proteins; C092812:SAM37 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D013431:Sulfates; D013462:Sulfur Radioisotopes