Human Mpp11 J protein: ribosome-tethered molecular chaperones are ubiquitous.
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.
Hundley
Heather A
HA
Department of Biochemistry, 433 Babcock Drive, University of Wisconsin-Madison, Madison, WI 53706, USA.
Walter
William
W
Bairstow
Shawn
S
Craig
Elizabeth A
EA
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
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