Assembly principles of the human R2TP chaperone complex reveal the presence of R2T and R2P complexes

Structure. 2022 Jan 6;30(1):156-171.e12. doi: 10.1016/j.str.2021.08.002. Epub 2021 Sep 6.

Abstract

R2TP is a highly conserved chaperone complex formed by two AAA+ ATPases, RUVBL1 and RUVBL2, that associate with PIH1D1 and RPAP3 proteins. R2TP acts in promoting macromolecular complex formation. Here, we establish the principles of R2TP assembly. Three distinct RUVBL1/2-based complexes are identified: R2TP, RUVBL1/2-RPAP3 (R2T), and RUVBL1/2-PIH1D1 (R2P). Interestingly, we find that PIH1D1 does not bind to RUVBL1/RUVBL2 in R2TP and does not function as a nucleotide exchange factor; instead, RPAP3 is found to be the central subunit coordinating R2TP architecture and linking PIH1D1 and RUVBL1/2. We also report that RPAP3 contains an intrinsically disordered N-terminal domain mediating interactions with substrates whose sequences are primarily enriched for Armadillo repeat domains and other helical-type domains. Our work provides a clear and consistent model of R2TP complex structure and gives important insights into how a chaperone machine concerned with assembly of folded proteins into multisubunit complexes might work.

Keywords: AAA+ proteins; ATPases; PAQosome; R2TP; RUVBL1/2; macromolecular complex assembly; molecular chaperones; protein folding.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • ATPases Associated with Diverse Cellular Activities / chemistry
  • ATPases Associated with Diverse Cellular Activities / metabolism*
  • Apoptosis Regulatory Proteins / chemistry
  • Apoptosis Regulatory Proteins / metabolism*
  • Binding Sites
  • Carrier Proteins / chemistry
  • Carrier Proteins / metabolism*
  • Chromatography, Gel
  • DNA Helicases / chemistry
  • DNA Helicases / metabolism*
  • Humans
  • Models, Molecular
  • Multiprotein Complexes / chemistry*
  • Multiprotein Complexes / metabolism
  • Protein Conformation
  • Protein Domains
  • Protein Structure, Quaternary

Substances

  • Apoptosis Regulatory Proteins
  • Carrier Proteins
  • Multiprotein Complexes
  • PIH1D1 protein, human
  • RPAP3 protein, human
  • ATPases Associated with Diverse Cellular Activities
  • DNA Helicases
  • RUVBL1 protein, human
  • RUVBL2 protein, human