Extended Data Fig. 8: PDIA6 domain b recruits BiP into the condensates.
From: A multichaperone condensate enhances protein folding in the endoplasmic reticulum
a, Quantification of enrichment of BiP in endogenous PDIA6 condensates (left, n = 25 cells, pooled across three independent experiments, a total of 2,300 condensates were counted) and in transiently transfected PDIA6–GFP condensates (right, n = 31 cells, pooled across three independent experiments, a total of 720 condensates were counted). Mean and standard deviation. b, Co-localization of overexpressed PDIA6–GFP (pink) and overexpressed BiP–mCherry (blue) in live HeLa cells (left) and of endogenous PDIA6 (pink) and overexpressed BiP–mCherry (blue) in fixed HeLa cells (right). PDIA6–GFP was visualized by imaging eGFP, BiP–mCherry by imaging mCherry. Scale bar, 20 μm, insert 5 μm. c, Co-localization of overexpressed PDIA6–GFP (pink) and endogenous BiP (blue) in fixed HeLa cells at low (left) and high (right) exposure. Scale bar, 10 μm. d, Overlay of 2D [13C,1H]-HMQC spectra of 100 μM PDIA6 in absence (black) and in presence of 2 eq. BiP (blue). Full spectra shown in Supplementary Fig. 5a. e, Overlay of 2D [15N,1H]-HSQC spectra of 100 μM PDIA6 domain ab in absence (black) and in presence of 2 eq. BiP (blue). Full spectra shown in Supplementary Fig. 5b. f, Combined methyl chemical shift perturbation of PDIA6 upon titration of 2 eq. BiP. The magnitudes of 1.5 SD and 2 SDs are indicated by pink lines. g, Combined amide chemical shift perturbation of PDIA6 domain ab upon titration of BiP. The magnitude of 1.5 SD is indicated by a purple line, disappearing residues in blue. h, Methyl groups with substantial CSP upon interaction with BiP shown as pink spheres on the structure of domain b. Amide groups with substantial CSP are shown as purple surface. i, Overlay of 2D [13C,1H]-HMQC spectra of 100 μM methyl-labelled BiP in absence (black) and in presence of 2 eq. PDIA6 (blue). Full spectra shown in Supplementary Fig. 6. j, Combined methyl chemical shift perturbation of BiP upon titration of 2 eq. PDIA6. The magnitudes of 2 SDs is indicated by a blue line. k, Methyl groups with substantial CSP upon interaction with PDIA6 shown as blue spheres on the structure of the undocked ADP-bound BiP (modelled on PDB: 2kho). l, Microscale thermophoresis signal of Dylight 488–PDIA6 plotted against BiP concentration in presence of 1 mM Ca2+. Mean and standard deviation (n = 3, technical triplicates).
