Chaperone Function of Hgh1 in the Biogenesis of Eukaryotic Elongation Factor 2

Mönkemeyer, Leonie; Klaips, Courtney L.; Balchin, David; Körner, Roman; Hartl, F. Ulrich; Bracher, A.

doi:10.1016/j.molcel.2019.01.034

Cited by 20 publications

(14 citation statements)

References 71 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…EF-G is highly conserved across all kingdoms of life. Efficient folding of the eukaryotic EF-G ortholog eEF2 requires a specialized chaperone, Hgh1, that likely binds cotranslationally, stabilizes domain III, and recruits additional chaperones, including the TRiC chaperonin and possibly Hsp90, to the nascent polypeptide (61, 62). Bacteria lack Hgh1 and likely use other chaperone systems to reduce misfolding during synthesis.…”

Section: Discussionmentioning

confidence: 99%

Energetic dependencies dictate folding mechanism in a complex protein

Liu

Chen

Kaiser

2019

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Large proteins with multiple domains are thought to fold cotranslationally to minimize interdomain misfolding. Once folded, domains interact with each other through the formation of extensive interfaces that are important for protein stability and function. However, multidomain protein folding and the energetics of domain interactions remain poorly understood. In elongation factor G (EF-G), a highly conserved protein composed of 5 domains, the 2 N-terminal domains form a stably structured unit cotranslationally. Using single-molecule optical tweezers, we have defined the steps leading to fully folded EF-G. We find that the central domain III of EF-G is highly dynamic and does not fold upon emerging from the ribosome. Surprisingly, a large interface with the N-terminal domains does not contribute to the stability of domain III. Instead, it requires interactions with its folded C-terminal neighbors to be stably structured. Because of the directionality of protein synthesis, this energetic dependency of domain III on its C-terminal neighbors disrupts cotranslational folding and imposes a posttranslational mechanism on the folding of the C-terminal part of EF-G. As a consequence, unfolded domains accumulate during synthesis, leading to the extensive population of misfolded species that interfere with productive folding. Domain III flexibility enables large-scale conformational transitions that are part of the EF-G functional cycle during ribosome translocation. Our results suggest that energetic tuning of domain stabilities, which is likely crucial for EF-G function, complicates the folding of this large multidomain protein.

show abstract

Section: Discussionmentioning

confidence: 99%

Energetic dependencies dictate folding mechanism in a complex protein

Liu

Chen

Kaiser

2019

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

show abstract

“…The CCT/TRiC chaperone system seems also to be involved in eEF2 folding, as human Hgh1 was reported to interact with CCT/TRiC (Hein et al, 2015), and yeast eEF2 is a client of CCT/TRiC (R€ ußmann et al, 2012). Interestingly, Bracher, Hartl, and colleagues could show that Hgh1 acts as a recruiting factor for CCT/TRiC fostering the interaction of eEF2 with this chaperone complex (Mö nkemeyer et al, 2019 [in this issue of Molecular Cell]). These findings suggest that Hgh1 recruits both the CCT/TRiC and the Hsp90 chaperone systems for eEF2 folding.…”

Section: Discussionmentioning

confidence: 99%

The Co-chaperone Cns1 and the Recruiter Protein Hgh1 Link Hsp90 to Translation Elongation via Chaperoning Elongation Factor 2

et al. 2019

View full text Add to dashboard Cite

Graphical AbstractHighlights d Cns1 contains a disordered region, a TPR domain, and a domain with a novel fold d Cns1's essential function is associated with protein translation d Cns1, Hgh1, and Hsp90 form a complex with eEF2d The Cns1 complex including the co-factor Hgh1 chaperones eEF2 SUMMARYThe Hsp90 chaperone machinery in eukaryotes comprises a number of distinct accessory factors. Cns1 is one of the few essential co-chaperones in yeast, but its structure and function remained unknown.Here, we report the X-ray structure of the Cns1 fold and NMR studies on the partly disordered, essential segment of the protein. We demonstrate that Cns1 is important for maintaining translation elongation, specifically chaperoning the elongation factor eEF2. In this context, Cns1 interacts with the novel co-factor Hgh1 and forms a quaternary complex together with eEF2 and Hsp90. The in vivo folding and solubility of eEF2 depend on the presence of these proteins. Chaperoning of eEF2 by Cns1 is essential for yeast viability and requires a defined subset of the Hsp90 machinery as well as the identified eEF2 recruiting factor Hgh1.

show abstract

“…In this case, the ribosome, together with trigger factor (TF), a cotranslationally acting chaperone, aids early folding steps to establish the correct path for folding [101]. Notably, in vivo folding of the eukaryotic homolog of EF-G, eEF2, requires the help of chaperones [102,103]. Interestingly, recent work on the cotranslational folding of domain III of EF-G shows that this domain is not stabilized by its N-terminal neighbors (domain G and domain II) and requires interactions with the C-terminal domains (domains IV and V) to adopt a stable structure [104].…”

Section: Multidomain Protein Foldingmentioning

confidence: 99%

Cotranslational Folding of Proteins on the Ribosome

2020

View full text Add to dashboard Cite

Many proteins in the cell fold cotranslationally within the restricted space of the polypeptide exit tunnel or at the surface of the ribosome. A growing body of evidence suggests that the ribosome can alter the folding trajectory in many different ways. In this review, we summarize the recent examples of how translation affects folding of single-domain, multiple-domain and oligomeric proteins. The vectorial nature of translation, the spatial constraints of the exit tunnel, and the electrostatic properties of the ribosome-nascent peptide complex define the onset of early folding events. The ribosome can facilitate protein compaction, induce the formation of intermediates that are not observed in solution, or delay the onset of folding. Examples of single-domain proteins suggest that early compaction events can define the folding pathway for some types of domain structures. Folding of multi-domain proteins proceeds in a domain-wise fashion, with each domain having its role in stabilizing or destabilizing neighboring domains. Finally, the assembly of protein complexes can also begin cotranslationally. In all these cases, the ribosome helps the nascent protein to attain a native fold and avoid the kinetic traps of misfolding.

show abstract

Chaperone Function of Hgh1 in the Biogenesis of Eukaryotic Elongation Factor 2

Cited by 20 publications

References 71 publications

Energetic dependencies dictate folding mechanism in a complex protein

Energetic dependencies dictate folding mechanism in a complex protein

The Co-chaperone Cns1 and the Recruiter Protein Hgh1 Link Hsp90 to Translation Elongation via Chaperoning Elongation Factor 2

Cotranslational Folding of Proteins on the Ribosome

Contact Info

Product

Resources

About