Abstract
Mdj1p, a novel member of the DnaJ family, is a heat shock protein that is associated with the inner membrane of mitochondria of Saccharomyces cerevisiae. Disruption of the MDJ1 gene resulted in a petite phenotype, loss of mitochondrial DNA, and inviability at 37 degrees C. Import of precursor proteins was not affected by a lack of Mdj1p, but folding of newly imported proteins was markedly impaired. The efficiency of refolding of a tester protein, dihydrofolate reductase, was significantly reduced in mitochondria lacking Mdj1p after incubation at elevated temperature. We conclude that Mdj1p is an important mitochondrial chaperone that participates in the folding of newly imported proteins and in the protection of proteins against heat denaturation and aggregation.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Base Sequence
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Conserved Sequence
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DNA, Fungal / analysis
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DNA, Mitochondrial / analysis
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Fungal Proteins / chemistry
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Fungal Proteins / metabolism
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Genes, Fungal / genetics*
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HSP40 Heat-Shock Proteins
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Heat-Shock Proteins / chemistry
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Heat-Shock Proteins / genetics*
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Heat-Shock Proteins / metabolism
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Hot Temperature
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Membrane Proteins / chemistry
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Membrane Proteins / genetics*
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Membrane Proteins / metabolism
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Mitochondria / chemistry
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Mitochondria / metabolism*
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Molecular Sequence Data
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Protein Denaturation
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Protein Folding*
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Protein Precursors / metabolism
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Saccharomyces cerevisiae / genetics*
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Saccharomyces cerevisiae / growth & development
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Saccharomyces cerevisiae Proteins*
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Sequence Alignment
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Sequence Analysis, DNA
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Spores, Fungal
Substances
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DNA, Fungal
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DNA, Mitochondrial
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Fungal Proteins
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HSP40 Heat-Shock Proteins
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Heat-Shock Proteins
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MDJ1 protein, S cerevisiae
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Membrane Proteins
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Protein Precursors
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Saccharomyces cerevisiae Proteins