The Chaperonin TRiC/CCT Associates with Prefoldin through a Conserved Electrostatic Interface Essential for Cellular Proteostasis.Gestaut, D., Roh, S.H., Ma, B., Pintilie, G., Joachimiak, L.A., Leitner, A., Walzthoeni, T., Aebersold, R., Chiu, W., Frydman, J.
(2019) Cell 177: 751-765.e15
- PubMed: 30955883
- DOI: https://doi.org/10.1016/j.cell.2019.03.012
- Primary Citation of Related Structures:
6NR8, 6NR9, 6NRA, 6NRB, 6NRC, 6NRD
- PubMed Abstract:
Maintaining proteostasis in eukaryotic protein folding involves cooperation of distinct chaperone systems. To understand how the essential ring-shaped chaperonin TRiC/CCT cooperates with the chaperone prefoldin/GIMc (PFD), we integrate cryoelectron microscopy (cryo-EM), crosslinking-mass-spectrometry and biochemical and cellular approaches to elucidate the structural and functional interplay between TRiC/CCT and PFD. We find these hetero-oligomeric chaperones associate in a defined architecture, through a conserved interface of electrostatic contacts that serves as a pivot point for a TRiC-PFD conformational cycle. PFD alternates between an open "latched" conformation and a closed "engaged" conformation that aligns the PFD-TRiC substrate binding chambers. PFD can act after TRiC bound its substrates to enhance the rate and yield of the folding reaction, suppressing non-productive reaction cycles. Disrupting the TRiC-PFD interaction in vivo is strongly deleterious, leading to accumulation of amyloid aggregates. The supra-chaperone assembly formed by PFD and TRiC is essential to prevent toxic conformations and ensure effective cellular proteostasis.
Department of Biology and Genetics, Stanford University, Stanford, CA 94305, USA.