Fig. 2.

xIP-MS reveals that CSA interacts with the TRiC inner pocket. a LFQ analysis after CSA-GFP pulldown indicates that all TRiC subunits interact with CSA even after stringent washing. Ratio of protein signal in GFP vs. non-GFP pulldowns is plotted on the x-axis, and the significance of the difference, −log₁₀(p-value), is plotted on the y-axis. Cutoffs are selected such that no protein significantly interacted with the non-GFP control beads. b iBAQ-based stoichiometry of selected interactors relative to the bait protein (CSA), which was set to 1. c Cross-linking map of all identified residue linkages. TRiC subunits are displayed in linear form with intra-links indicated in gray. The presence of ambiguous linkages (where multiple subunits have the same peptide) is indicated by dashed lines. Inter-protein linkages are indicated in blue. d CSA inter-protein linkages with the TRiC octamer (colored light gray) indicate that CSA binds the TRiC inner pocket. Inter-protein cross-links are colored dark-blue. CSA (colored dark gray) was positioned manually to give a visual interpretation to possible CSA-TRiC interactions. The accessible CSA interaction space satisfying 10/11 inter-protein cross-links is shown as a light blue cloud