Abstract
Pex5p, which is the import receptor for peroxisomal matrix proteins harboring a type I signal sequence (PTS1), is mono- and polyubiquitinated in Saccharomyces cerevisiae. We identified Pex5p as a molecular target for Pex4p-dependent monoubiquitination and demonstrated that either poly- or monoubiquitination of the receptor is required for the ATP-dependent release of the protein from the peroxisomal membrane to the cytosol as part of the receptor cycle. Therefore, the energy requirement of the peroxisomal import pathway has to be extended by a second ATP-dependent step, namely receptor monoubiquitination.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Cytosol / metabolism
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Intracellular Membranes / metabolism
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Membrane Transport Proteins / metabolism*
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Models, Biological
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Peroxins
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Peroxisome-Targeting Signal 1 Receptor
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Peroxisomes / metabolism*
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Polyubiquitin / metabolism
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Protein Processing, Post-Translational*
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Protein Transport
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Saccharomyces cerevisiae / metabolism*
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Saccharomyces cerevisiae Proteins / metabolism
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Second Messenger Systems
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Ubiquitin / metabolism*
Substances
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Membrane Transport Proteins
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PEX4 protein, S cerevisiae
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PEX5 protein, S cerevisiae
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Peroxins
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Peroxisome-Targeting Signal 1 Receptor
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Saccharomyces cerevisiae Proteins
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Ubiquitin
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Polyubiquitin