Jaiswal H, et al. (2011) The chaperone network connected to human ribosome-associated complex. Mol Cell Biol 31(6):1160-73
Abstract: Mammalian ribosome-associated complex (mRAC), consisting of the J-domain protein MPP11 and the atypical Hsp70 homolog (70-homolog) Hsp70L1, can partly complement for the function of RAC, which is the homologous complex from yeast. RAC is the J-domain partner exclusively of the 70-homolog Ssb, which directly and independently of RAC binds to the ribosome. We here show, that growth defects due to mRAC-depletion in HeLa cells resemble those of yeast strains lacking RAC. Functional conservation, however, did not extend to the 70-homolog partner of mRAC. None of the major human 70-homologs was able to complement growth defects of yeast strains lacking Ssb, or was bound to ribosomes in an Ssb-like manner. Instead, our data suggest that mRAC was a specific partner of human Hsp70, but not of its close homolog, Hsc70. On a mechanistic level, ATP-binding, but not ATP hydrolysis, by Hsp70L1 affected mRACs function as a J-domain partner of Hsp70. The combined data indicate that, while functionally conserved, yeast and mammalian cells have evolved distinct solutions to ensure that Hsp70-type chaperones can efficiently assist the biogenesis of newly synthesized polypeptide chains.
|Status: Published||Type: Journal Article||PubMed ID: 21245388|
Topics addressed in this paper
Number of different genes curated to this paper: 9
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