Fig. 6: INPP5A controls surface lipid homeostasis by regulating IP3 levels. | Nature Communications

Fig. 6: INPP5A controls surface lipid homeostasis by regulating IP3 levels.

From: Inositol triphosphate-triggered calcium release blocks lipid exchange at endoplasmic reticulum-Golgi contact sites

Fig. 6

a Schematic of IP3 pathway. PLC, phospholipase C, DAG, diacylglycerol; IP3R, IP3 receptors. b [IP3] (picomole/500,000 cells) in HeLa cells treated with control or INPP5A siRNA (5AKD). Two-tailed paired t-test, p = 0.0265, t = 6.021, df = 2. Mean ± SEM, n = 3. c Surface binding and uptake of Shiga toxin (STX) in HeLa cells treated with the indicated siRNAs. Data for control set to 1. One sample t-test with Benjamini–Hochberg correction. Uptake ITPKBKD: p = 0.0002, t = 18.47, df = = 4. Uptake ITPKBKD + 5AKD: p = 0.0019, t = 23, df = 2. Surface ITPKBKD: p = 0.0002, t = 13.66, df =3. Surface ITPKBKD + 5AKD: p = 0.0008, t = 169.7, df = 2. Mean ± SEM, n = 3 (ITBKBKD + 5AKD), 4 (ITPKKD surface), or 5 (ITPKBD Uptake). d STX uptake in HeLa cells treated with PEI-II or DMSO. One sample t-test: p = 0.0064, t = 6.84, df = 3. Mean ± SEM, n = 4. e STX uptake in HeLa depleted of endogenous INPP5A expressing siRNA-resistant wild-type (WT) or phosphatase-dead (Mut) INPP5A. One sample t-test with Benjamini–Hochberg correction. -/5AKD: p = 0.0327, t = 9.492, df = 2. Mut/5AKD: p = 0.0.0435, t = 3.456, df = 2. Res/5AKD: p = 0.2225, t = 1.534, df = 3. Mean ± SEM, n = 3 (5AKD alone) or 4 (INPP5A transfections). f, g Relative Ca2+ levels determined by Fluo-4 in HeLa cells treated with control (SCR, set to 1) or INPP5A siRNA (5AKD). g Representative images, Scale bar, 25 μm. f Quantified data from n = 3. One sample t-test. 5AKD: p = 0.0217, t = 6.671, df = 2. h Rescue of defective STX uptake by BAPTA-AM. One sample t-test followed by Benjamini–Hochberg correction. 5AKD: p = 0.005, t = 42.70, df = 2. BAPTA/SCR: p = 0.0136, t = 8.488, df = 2. BAPTA/5AKD: p = 0.9762, t = 0.03365, df = 2. Mean ± SEM, n = 3. i Rescue of defective STX uptake by IP3R depletion. Relative STX uptake in HeLa cells treated with the indicated siRNAs. One sample t-test 5AKD: p < 0.0001, t = 17.94, df = 5. IPRsKD: p = 0.9866, t = 0.0176, df = 5. IPRsKS+5AKD = 0.0513, t = 2.55, df = 5 Mean ± SEM, n = 6. j PLC activation by m-3M3FBS inhibits STX uptake. One sample t-test m-3M3FBS: p = 0.0005, t = 46.51, df = 2. Mean ± SEM, n = 3. n denotes number of independent experiments, Numerical source data are reported in the Source Data file.

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