Fig 2: Schematic diagram to show the effect of PDI regulating autophagy in CRC.Under radio/chemo-therapy conditions, PDI interacts with GRP78 to inhibit the degradation of AKT, and eventually activates the mTOR pathway and inhibits autophagy initiation. In parallel, radio/chemo-therapy mediates the transfer of PDI from the ER to mitochondria, and translocated PDI competes with LC3 to bind PHB2 on mitochondria to inhibit mitophagy.

Fig 3: Depletion of DRP1 from PINCH-1 KO cells promotes kindlin-2-PYCR1 interaction.a PINCH-1 KO A549 cells were transfected with Si-DRP1 or Si-con as indicated. Three days later, cells (as indicated) were analyzed by Western blotting with antibodies recognizing PYCR1, DRP1, PINCH-1, or tubulin. PYCR1 level was quantified by densitometry (right, n = 4; A549 vs P1KO P = 0.0076, A549 vs P1KO + Si-con P = 0.0023, P1KO vs P1KO + Si-DRP1 P = 0.0419, P1KO + Si-con vs P1KO + Si-DRP1 P = 0.012). b The cytosolic (Cyto) (lane 5, 7, 9 and 11), mitochondrial (Mito) (lane 6, 8, 10, and 12) and total (lane 1, 2, 3, and 4) fractions from the cells were analyzed by Western blotting with antibodies recognizing kindlin-2 (K2), PHB2, or tubulin. Kindlin-2 level in mitochondria was quantified (right, n = 3; A549 vs P1KO P < 0.0001, A549 vs P1KO + Si-con P < 0.0001, P1KO vs P1KO + Si-DRP1 P < 0.0001, P1KO + Si-con vs P1KO + Si-DRP1 P < 0.0001). c Cells were analyzed by PLA with kindlin-2 and PYCR1 antibodies. Bar, 10 µm. The number of PLA dots per cell were counted (right, n = 40 cells; A549 vs P1KO P < 0.0001, A549 vs P1KO + Si-con P < 0.0001, P1KO vs P1KO + Si-DRP1 P < 0.0001, P1KO + Si-con vs P1KO + Si-DRP1 P < 0.0001). d Cells (as indicated) were analyzed by IP and Western blotting. Lane 2, the sample was prepared as that of lane 3 except anti-kindlin-2 antibody was substituted with irrelevant mouse IgG. PYCR1 level was quantified by densitometry (right, n = 4; A549 vs P1KO P < 0.0001, A549 vs P1KO + Si-con P < 0.0001, P1KO vs P1KO + Si-DRP1 P < 0.0001, P1KO + Si-con vs P1KO + Si-DRP1 P < 0.0001). e The proline level was analyzed using the absorbance method as described in the “Methods” (right, n = 3 independent experiments; A549 vs P1KO P < 0.0001, A549 vs P1KO + Si-con P < 0.0001, P1KO vs P1KO + Si-DRP1 P = 0.0086, P1KO + Si-con vs P1KO + Si-DRP1 P = 0.0058). A representative set of samples were shown in the left. Bar, 1 cm. f A549 cells were infected with lentiviral vector encoding 3xFLAG-tagged MFN2 (3f-MFN2) or with 3xFLAG vector (3f). Three days later, the cells were analyzed by PLA with kindlin-2 and PYCR1 antibodies. Bar, 10 µm. The number of PLA dots per cell were counted (right, A549 n = 34 cells, 3f n = 33 cells, 3f-MFN2 n = 46 cells; A549 vs 3f-MFN2 P = 0.0074, 3f vs 3f-MFN2 P = 0.0027). g The cytosolic (lane 4, 6, and 8), mitochondrial (lane 5, 7, and 9) and total (lane 1, 2, and 3) fractions from the cells were analyzed by Western blotting. The levels of kindlin-2 in the cytosolic or mitochondrial fractions were quantified by densitometry. Right panel, the ratio of the mitochondrial kindlin-2 level divided by the cytosolic kindlin-2 level in the MFN2 overexpressing cells was compared to that in the control infectants or wild type A549 cells (normalized to 1, n = 3; A549 vs 3f-MFN2 P < 0.0001, 3f vs 3f-MFN2 P < 0.0001). Data in a–g represent mean ± SEM. Statistical significance was calculated using one-way ANOVA with Tukey–Kramer post-hoc analysis, *P < 0.05; **P < 0.01; ***P < 0.001. The samples in a, b, d, and g were from the same experiment and the blots were processed in parallel. Source data are provided as a Source Data file.

Fig 4: Cardiac-specific knockout of prohibitin 2 (Phb2) leads to dilated cardiomyopathy and heart failure.a Western blot analysis of PHB2 in the heart tissues from wild type (WT) and Phb2 cardiac-specific knockout (cKO) mice at 6 weeks of age (left). Anti-TIM23 immunoblot is used as the reference. Statistics for western blot (right). n = 6 mice per group. b Kaplan-Meier survival curves for WT and Phb2 cKO mice. n = 14 mice per group. Significance was determined by the Kaplan–Meier survival analysis. **p < 0.01 versus WT group. c HE staining of gross morphology from WT and Phb2 cKO mouse hearts at 8 weeks of age. Scale bar: 1 mm. d Fibrosis of the heart tissues from 8-week-old WT and Phb2 cKO mice was assessed by Masson staining (left). Statistics for fibrotic areas (right). n = 3 independent experiments per group. Scale bar: 1 mm. e Representative echocardiographic images of the left ventricle in WT and Phb2 cKO mouse hearts at 8 weeks of age. n = 6 mice per group. f Echocardiographic analysis of EF (ejection fraction) and FS (fractional shortening). g Echocardiographic statistics of LVID; d (LV internal diameter at end-diastole) and LVID; s (LV internal diameter at end-systole). h Echocardiographic statistics of LV Vol; d (left ventricular volume at end-diastole) and LV Vol; s (left ventricular volume at end-systole). i Echocardiographic statistics of LVPW; d (left ventricular posterior wall at end-diastole) and LVPW; s (left ventricular posterior wall at end-systole). j The ratio of heart weight (HW) to body weight (BW) and heart weight (HW) to tibia length (TL) from 8-week-old WT and Phb2 cKO mice. n = 6 independent experiments per group. All Data represent mean ± SEM. Significance was determined by two-tailed, unpaired Student’s t test. ns: no significance. **p < 0.01, ***p < 0.001 versus WT group.

Fig 5: Impaired fatty acid oxidation (FAO) and cardiac lipid accumulation are caused by PHB2 ablation.a Representative confocal images of lipid droplets (LD) visualized by BODIPY™ 493/503 in isolated cardiomyocytes from 6-week-old WT and Phb2 cKO mice (left). Scale bar: 20 µm. The enlargement is the magnification of the boxed inset shown in left panel. Scale bar: 5 µm. Statistics of fold change of LD number, area and fluorescence intensity per cardiomyocyte (right). n = 80–100 cells from six mice per group. b Measurement of fatty acid oxidation (FAO) in isolated cardiomyocytes from 6-week-old WT and Phb2 cKO mice. Arrowhead indicates the time points of adding BSA (0.17 mM) or BSA-Pal (Palmitate) (1 mM). n = 3 mice per group. c Representative confocal images of fatty acid uptake (FAU) visualized by BODIPY™ 500/510 in isolated cardiomyocytes from 6-week-old WT and Phb2 cKO mice (top). Statistics of FAU levels (bottom). n = 80–100 cells from six mice per group. Scale bar: 50 µm. All Data represent mean ± SEM. Significance was determined by two-tailed, unpaired Student’s t test. ns: no significance. **p < 0.01, ***p < 0.001 versus WT group.