Abstract
The BCS1 protein is anchored in the mitochondrial inner membrane via a single transmembrane domain and has an N(out)-C(in) topology. Unlike the majority of nuclear encoded mitochondrial preproteins, the BCS1 protein does not contain an N-terminal targeting sequence. A positively charged segment of amino acids which is located immediately C-terminal to the transmembrane domain acts as an internal targeting signal. In order to function, we postulate that this sequence co-operates with the transmembrane domain to form a tight hairpin loop structure. This loop is translocated across the inner membrane via the MIM/mt-Hsp70 machinery in a membrane potential-dependent manner. This novel mechanism of import and sorting of the BCS1 protein is proposed to represent a more general mechanism used by a number of inner membrane proteins.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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ATPases Associated with Diverse Cellular Activities
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Amino Acid Sequence
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Base Sequence
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Biological Transport, Active
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Cloning, Molecular
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DNA Primers / genetics
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DNA, Fungal / genetics
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Intracellular Membranes / metabolism
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Membrane Proteins
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Mitochondria / metabolism*
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Mitochondrial Proteins
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Models, Biological
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Molecular Chaperones
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Molecular Sequence Data
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Molecular Structure
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Protein Sorting Signals / genetics
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Recombinant Fusion Proteins / genetics
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Recombinant Fusion Proteins / metabolism
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Saccharomyces cerevisiae / genetics
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Saccharomyces cerevisiae / metabolism*
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Saccharomyces cerevisiae Proteins
Substances
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BCS1 protein, S cerevisiae
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DNA Primers
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DNA, Fungal
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Membrane Proteins
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Mitochondrial Proteins
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Molecular Chaperones
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Protein Sorting Signals
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Recombinant Fusion Proteins
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Saccharomyces cerevisiae Proteins
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ATPases Associated with Diverse Cellular Activities