Fraction of nascent chains encoding cytosolic and nuclear proteins that are bound to Hsp70 SSB

Range ~80 %
Organism Budding yeast Saccharomyces cerevisiae
Reference Willmund et al., The cotranslational function of ribosome-associated Hsp70 in eukaryotic protein homeostasis. Cell. 2013 Jan 17 152(1-2):196-209. doi: 10.1016/j.cell.2012.12.001. p.199 left column 2nd paragraphPubMed ID23332755
Method P.197 right column bottom paragraph: "SSB-associated nascent chains were identified through their mRNAs using three independent experiments carried out as biological replicates. The experiments were highly reproducible, as underscored by their high correlation coefficient (r = 0.92) following hierarchical clustering analysis (Figure S1F). Comparing the SSB-bound data set to both the Translatome and the cotranslational interactome of SRP [signal recognition particle] revealed clear differences in specificity between SSB and SRP as well as differences between the SSB interactome and the Translatome (Figure 1E). [Investigators'] data indicate that SSB does not bind to every nascent chain complex, allowing [them] to define “SSB-bound” and “non-SSB-bound” data sets (Figure 1E, see also Figure 4A)."
Comments P.199 left column 2nd paragraph: "Systems-Level Analysis of SSB Specificity: [Investigators] next examined the overall characteristics of SSB-associated nascent polypeptides. In contrast to SRP, which binds secretory and membrane proteins, SSB preferentially binds to cytosolic and nuclear proteins (Figure 2C). The overlap between SSB-bound and SRP-bound nascent chains was negligible (Figure 2C, inset, Figure 1E). These results suggest that SSB and SRP binding to nascent polypeptides are mutually exclusive and that SSB binds to a large subset of approximately 80% of nascent chains encoding cytosolic and nuclear proteins (Figure 2D)."
Entered by Uri M
ID 113366