Co-translational involvement of the chaperonin GroEL in the folding of newly translated polypeptides

Bei Wen Ying, Hideki Taguchi, Mayumi Kondo, Takuya Ueda

Research output: Contribution to journalArticlepeer-review

49 Citations (Scopus)

Abstract

A large fraction of the newly translated polypeptides emerging from the ribosome require certain proteins, the so-called molecular chaperones, to assist in their folding. In Escherichia coli, three major chaperone systems are considered to contribute to the folding of newly synthesized cytosolic polypeptides. Trigger factor (TF), a ribosome-tethered chaperone, and DnaK are known to exhibit overlapping co-translational roles, whereas the cage-shaped GroEL, with the aid of the co-chaperonin, GroES, and ATP, is believed to be implicated in folding only after the polypeptides are released from the ribosome. However, the recent finding that GroEL-GroES overproduction permits the growth of E. coli cells lacking both TF and DnaK raised questions regarding the separate roles of these chaperones. Here, we report the puromycin-sensitive association of GroEL-GroES with translating ribosomes in vivo. Further experiments in vitro, using a reconstituted cell-free translation system, clearly demonstrate that GroEL associates with the translation complex and accomplishes proper folding by encapsulating the newly translated polypeptides in the central cavity formed by GroES. Therefore, we propose that GroEL is a versatile chaperone, which participates in the folding pathway co-translationally and also achieves correct folding post-translationally.

Original languageEnglish
Pages (from-to)12035-12040
Number of pages6
JournalJournal of Biological Chemistry
Volume280
Issue number12
DOIs
Publication statusPublished - 2005 Mar 25
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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