Structural visualization of the tubulin folding pathway directed by human chaperonin TRiC/CCT.
Cell
; 185(25): 4770-4787.e20, 2022 Dec 08.
Article
in En
| MEDLINE
| ID: mdl-36493755
ABSTRACT
The ATP-dependent ring-shaped chaperonin TRiC/CCT is essential for cellular proteostasis. To uncover why some eukaryotic proteins can only fold with TRiC assistance, we reconstituted the folding of ß-tubulin using human prefoldin and TRiC. We find unstructured ß-tubulin is delivered by prefoldin to the open TRiC chamber followed by ATP-dependent chamber closure. Cryo-EM resolves four near-atomic-resolution structures containing progressively folded ß-tubulin intermediates within the closed TRiC chamber, culminating in native tubulin. This substrate folding pathway appears closely guided by site-specific interactions with conserved regions in the TRiC chamber. Initial electrostatic interactions between the TRiC interior wall and both the folded tubulin N domain and its C-terminal E-hook tail establish the native substrate topology, thus enabling C-domain folding. Intrinsically disordered CCT C termini within the chamber promote subsequent folding of tubulin's core and middle domains and GTP-binding. Thus, TRiC's chamber provides chemical and topological directives that shape the folding landscape of its obligate substrates.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Tubulin
/
Chaperonin Containing TCP-1
Limits:
Humans
Language:
En
Journal:
Cell
Year:
2022
Document type:
Article
Affiliation country:
Estados Unidos