A dual function for chaperones SSB–RAC and the NAC nascent polypeptide–associated complex on ribosomes
| Autor: | Steffen Preissler, Marc Erhardt, Annika Scior, Yulia Ilina, Ansgar Koplin, Elke Deuerling, Miriam Koch |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2010 |
| Předmět: |
Ribosomal Proteins
Protein Folding Saccharomyces cerevisiae Proteins Ribosome biogenesis Protein aggregation Biology Ribosome Models Biological Article Nucleotide exchange factor Cytosol stomatognathic system Ribosomal protein ddc:570 HSP70 Heat-Shock Proteins Research Articles Binding Sites Cell Biology Molecular biology Cell biology stomatognathic diseases Phenotype Protein folding Eukaryotic Ribosome Ribosomes Biogenesis Molecular Chaperones |
| Zdroj: | The Journal of Cell Biology |
| Popis: | In addition to assisting with protein folding, SSB and NAC also regulate ribosome biogenesis (see also companion paper from Albanèse et al. in this issue). The yeast Hsp70/40 system SSB–RAC (stress 70 B–ribosome-associated complex) binds to ribosomes and contacts nascent polypeptides to assist cotranslational folding. In this study, we demonstrate that nascent polypeptide–associated complex (NAC), another ribosome-tethered system, is functionally connected to SSB–RAC and the cytosolic Hsp70 network. Simultaneous deletions of genes encoding NAC and SSB caused conditional loss of cell viability under protein-folding stress conditions. Furthermore, NAC mutations revealed genetic interaction with a deletion of Sse1, a nucleotide exchange factor regulating the cytosolic Hsp70 network. Cells lacking SSB or Sse1 showed protein aggregation, which is enhanced by additional loss of NAC; however, these mutants differ in their potential client repertoire. Aggregation of ribosomal proteins and biogenesis factors accompanied by a pronounced deficiency in ribosomal particles and translating ribosomes only occurs in ssbΔ and nacΔssbΔ cells, suggesting that SSB and NAC control ribosome biogenesis. Thus, SSB–RAC and NAC assist protein folding and likewise have important functions for regulation of ribosome levels. These findings emphasize the concept that ribosome production is coordinated with the protein-folding capacity of ribosome-associated chaperones. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|