Abstract
The TOM complex of the outer membrane of mitochondria is the entry gate for the vast majority of precursor proteins that are imported into the mitochondria. It is made up by receptors and a protein conducting channel. Although precursor proteins of all subcompartments of mitochondria use the TOM complex, it is not known whether its channel can only mediate passage across the outer membrane or also lateral release into the outer membrane. To study this, we have generated fusion proteins of GFP and Tim23 which are inserted into the inner membrane and, at the same time, are spanning either the TOM complex or are integrated into the outer membrane. Our results demonstrate that the TOM complex, depending on sequence determinants in the precursors, can act both as a protein conducting pore and as an insertase mediating lateral release into the outer membrane.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Carrier Proteins / metabolism*
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Genes, Reporter
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Green Fluorescent Proteins / analysis
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Green Fluorescent Proteins / metabolism
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Membrane Proteins / metabolism*
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Membrane Transport Proteins / genetics
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Membrane Transport Proteins / metabolism*
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Mitochondrial Membrane Transport Proteins / chemistry
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Mitochondrial Membranes / metabolism*
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Mitochondrial Precursor Protein Import Complex Proteins
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Models, Molecular
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Protein Conformation
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Protein Folding
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Protein Precursors / metabolism
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Protein Structure, Tertiary
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Protein Transport
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Recombinant Fusion Proteins / metabolism
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Saccharomyces cerevisiae / growth & development
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Saccharomyces cerevisiae / metabolism
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Saccharomyces cerevisiae Proteins / chemistry
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Saccharomyces cerevisiae Proteins / genetics
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Saccharomyces cerevisiae Proteins / metabolism*
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Temperature
Substances
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Carrier Proteins
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MIM1 protein, S cerevisiae
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Membrane Proteins
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Membrane Transport Proteins
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Mitochondrial Membrane Transport Proteins
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Mitochondrial Precursor Protein Import Complex Proteins
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Protein Precursors
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Recombinant Fusion Proteins
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Saccharomyces cerevisiae Proteins
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TIM22 protein, S cerevisiae
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TIM23 protein, S cerevisiae
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Green Fluorescent Proteins