9e2s
Apo TRiC in closed conformation
Structural highlights
FunctionTCPQ_HUMAN Component of the chaperonin-containing T-complex (TRiC), a molecular chaperone complex that assists the folding of proteins upon ATP hydrolysis (PubMed:25467444). The TRiC complex mediates the folding of WRAP53/TCAB1, thereby regulating telomere maintenance (PubMed:25467444). As part of the TRiC complex may play a role in the assembly of BBSome, a complex involved in ciliogenesis regulating transports vesicles to the cilia (PubMed:20080638). The TRiC complex plays a role in the folding of actin and tubulin (Probable).[1] [2] Publication Abstract from PubMedThe folding nucleus (FN) initiates and enables an efficient protein folding pathway. Despite its essential role, the FN has long remained cryptic. Here we directly visualize the tubulin FN consisting of a nonnative, partially assembled Rossmann fold, in the closed chamber of human chaperonin TRiC. Chaperonin TRiC interacts with nonnatively folded secondary structure elements of tubulin, stabilizing the nucleus poised for transition into its first native domain tertiary structure. Through progressive folding into the native state, we observe that the unfolded sequence of tubulin undergoes drastic spatial rearrangement in the TRiC chamber to sample the conformational space, mediated by the highly dynamic CCT tails. The observed presence of individual nonnative secondary structure elements first in the nonnative FN and then around the incrementally folded native domains supports the hypothesis that tubulin folding in TRiC is a hierarchical process of nucleation, condensation and propagation in cooperation with TRiC subunits. Visualizing dynamic tubulin folding in chaperonin TRiC from nonnative nucleus to final native state.,Zhao Y, Schmid MF, Chiu W Nat Commun. 2025 Aug 23;16(1):7878. doi: 10.1038/s41467-025-63016-x. PMID:40849413[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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