Figure S3.

Canonical Complex Formation between BiP and IRE1, Related to Figure 4

(A) Coomassie-stained SDS-PAGE gel of biotinylated IRE1^LD-bio and BiP recovered on a streptavidin matrix from reactions constituted as in Figure 4B, with BiP or the nucleotide-binding domain of BiP (NBD) as indicated. Note: We have not been able to observe noncanonical complex formation between IRE1^LD and the BiP NBD.

(B) Fluorescence trace (Ex: 496 nm Em: 524 nm) of IRE1^LD-OG elution from a Sec3 size-exclusion chromatography column. Reaction mixtures of the indicated composition were incubated at 30°C for 20 minutes and clarified at 21,000 g for 5 minutes.

(C) Quantification of the effect of GRP170 on IRE1^LD-TAM association with IRE1^LD-bio, as in Figure 4G. Mean ± SD, n = 3, ^∗p = 0.0293 by Student’s paired ratio t test.