Figure 5. The unfolded protein CH1 dissociates the noncanonical interaction between BiP ATPase domain and the luminal domain of Ire1 or Perk.
(A) Pull down assay assessing the effects upon addition of unfolded protein CH1 to His6-tagged full-length BiP-luminal domain complexes. CH1 disrupts BiP-luminal domain interaction and causes the complexes to dissociate. (B) When His6-tagged full-length BiP is initially incubated with CH1 and then subsequently Ire1 and Perk luminal domains are added, we see no binding between luminal domains and BiP indicating that luminal domains and CH1 binding to BiP are mutually exclusive.