Abstract
The existence of specialized molecular chaperones that interact directly with ribosomes is well established in microorganisms. Such proteins bind polypeptides exiting the ribosomal tunnel and provide a physical link between translation and protein folding. We report that ribosome-associated molecular chaperones have been maintained throughout eukaryotic evolution, as illustrated by Mpp11, the human ortholog of the yeast ribosome-associated J protein Zuo. When expressed in yeast, Mpp11 partially substituted for Zuo by partnering with the multipurpose Hsp70 Ssa, the homolog of mammalian Hsc70. We propose that in metazoans, ribosome-associated Mpp11 recruits the multifunctional soluble Hsc70 to nascent polypeptide chains as they exit the ribosome.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Adenosine Diphosphate / metabolism
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Amino Acid Substitution
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Binding Sites
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Cell Line
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DNA-Binding Proteins / chemistry
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DNA-Binding Proteins / metabolism*
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HSC70 Heat-Shock Proteins
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HSP70 Heat-Shock Proteins / metabolism
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Humans
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Molecular Chaperones / chemistry
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Molecular Chaperones / metabolism*
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Oncogene Proteins / chemistry
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Oncogene Proteins / metabolism*
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Potassium Chloride / pharmacology
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Protein Structure, Tertiary
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RNA-Binding Proteins
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Ribosomes / metabolism*
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Saccharomyces cerevisiae / metabolism
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Saccharomyces cerevisiae Proteins / chemistry
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Saccharomyces cerevisiae Proteins / metabolism
Substances
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DNA-Binding Proteins
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DNAJC2 protein, human
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HSC70 Heat-Shock Proteins
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HSP70 Heat-Shock Proteins
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HSPA8 protein, human
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Molecular Chaperones
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Oncogene Proteins
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RNA-Binding Proteins
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Saccharomyces cerevisiae Proteins
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ZUO1 protein, S cerevisiae
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Adenosine Diphosphate
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Potassium Chloride