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. 2023 May 22;120(22):e2216857120. doi: 10.1073/pnas.2216857120

Fig. 3.

Fig. 3.

ER-resident oxidases activate the calcium-releasing activity of IP3R1. (A and B) The effect of ER oxidoreductin 1 (ERO1), PDI, and ERp46 on IP3-IICR. We established stable IP3 receptor 1 (IP3R1)/WT (A) or IP3R1/AACC (B) cell lines in IP3R TKO cells. After the transfection of the indicated FLAG-tagged PDIs, the cells were stimulated with 2 μM BK or 1 μM thapsigargin (Tg). IICR was measured by DeltaVision Elite with Yellow Cameleon 3.6 (YC3.6). Bar graph showing the mean amplitude (±SD) of the BK-induced Ca2+ peak (Upper) or Tg-stimulated Ca2+ leakage (Lower). *P < 0.05 and ***P < 0.001. (C) After transfection of the indicated FLAG-tagged PDIs, immunoprecipitates were prepared from lysates of cells stably expressing hemagglutinin (HA)-tagged IP3R1, and proteins were detected by immunoblotting using an antibody against the indicated peptide tags. (D) Schematic model of ERp46-mediated activation of IP3Rs through the ERO1-PDI hub complex. Red lines indicate the direction of electron transfer. Broken lines indicate a weak interaction or presumed electron transport.