Structural and Functional Analysis of GRP94 in the Closed State Reveals an Essential Role for the Pre-N Domain and a Potential Client-Binding Site

Cell Rep. 2017 Sep 19;20(12):2800-2809. doi: 10.1016/j.celrep.2017.08.079.


Hsp90 chaperones undergo ATP-driven conformational changes during the maturation of client proteins, populating a closed state upon ATP binding in which the N-terminal domains of the homodimer form a second inter-protomer dimer interface. A structure of GRP94, the endoplasmic reticulum hsp90, in a closed conformation has not been described, and the determinants that regulate closure are not well understood. Here, we determined the 2.6-Å structure of AMPPNP-bound GRP94 in the closed dimer conformation. The structure includes the pre-N domain, a region preceding the N-terminal domain that is highly conserved in GRP94, but not in other hsp90s. We show that the GRP94 pre-N domain is essential for client maturation, and we identify the pre-N domain as an important regulator of ATPase rates and dimer closure. The structure also reveals a GRP94:polypeptide interaction that partially mimics a client-bound state. The results provide structural insight into the ATP-dependent client maturation process of GRP94.

Keywords: GRP94; Hsp90; TRAP1; chaperone.

MeSH terms

  • Adenosine Triphosphatases / metabolism
  • Animals
  • Binding Sites
  • Dogs
  • HSP90 Heat-Shock Proteins / chemistry
  • HSP90 Heat-Shock Proteins / metabolism
  • Membrane Glycoproteins / chemistry*
  • Membrane Glycoproteins / metabolism*
  • Protein Domains
  • Protein Multimerization
  • Structure-Activity Relationship
  • Substrate Specificity


  • HSP90 Heat-Shock Proteins
  • Membrane Glycoproteins
  • endoplasmin
  • Adenosine Triphosphatases