title: Human Mpp11 J protein: ribosome-tethered molecular chaperones are ubiquitous.
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.
authors.affiliation: Department of Biochemistry, 433 Babcock Drive, University of Wisconsin-Madison, Madison, WI 53706, USA.
authors.forename: Heather A
authors.initials: HA
authors.lastname: Hundley
authors.forename: William
authors.initials: W
authors.lastname: Walter
authors.forename: Shawn
authors.initials: S
authors.lastname: Bairstow
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Craig
mesh_terms: D000244:Adenosine Diphosphate / Q000378:metabolism; D019943:Amino Acid Substitution; D001665:Binding Sites; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D050883:HSC70 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism; D006801:Humans; D018832:Molecular Chaperones / Q000737:chemistry / Q000378:metabolism*; D015513:Oncogene Proteins / Q000737:chemistry / Q000378:metabolism*; D011189:Potassium Chloride / Q000494:pharmacology; D017434:Protein Structure, Tertiary; D016601:RNA-Binding Proteins; D012270:Ribosomes / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000378:metabolism
chemical_list: D004268:DNA-Binding Proteins; C414672:DNAJC2 protein, human; D050883:HSC70 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; C494371:HSPA8 protein, human; D018832:Molecular Chaperones; D015513:Oncogene Proteins; D016601:RNA-Binding Proteins; D029701:Saccharomyces cerevisiae Proteins; C077019:ZUO1 protein, S cerevisiae; D000244:Adenosine Diphosphate; D011189:Potassium Chloride