RAC, a stable ribosome-associated complex in yeast formed by the DnaK-DnaJ homologs Ssz1p and zuotin

• DOI: 10.1073/pnas.071057198
• Publication Date: 2002-07-26T14:37:36Z
• Authors: Matthias Gautschi; Hauke Lilie; Ursula Fünfschilling; Andrej Mun; Suzanne Ross; Trevor Lithgow; Peter Rücknagel; Sabine Rospert
• Keywords: Chaperone (clinical)

The yeast cytosol contains multiple homologs of the DnaK and DnaJ chaperone family. Our current understanding which functionally interact is incomplete. Zuotin a homolog bound to ribosome. We have now identified Ssz1p/Pdr13p as zuotin's partner chaperone. Ssz1p form ribosome-associated complex (RAC) that ribosome via zuotin subunit. RAC unique among eukaryotic DnaK-DnaJ systems, 1:1 stable, even in presence ATP or ADP. In vitro , stimulates translocation ribosome-bound mitochondrial precursor protein into mitochondria, providing evidence for its chaperone-like effect on nascent chains. agreement with existence functional complex, deletion each subunit resulted similar phenotype vivo . However, overexpression partly rescued growth defect Δ ssz1 strain, whereas did not affect zuo1 suggesting pivotal function homolog.