Fig. 8: TIPE2 deficiency induces mitochondrial fission by potentiating IP3R-Ca2+-Drp1 axis in macrophages.
a Representative transmission electron microscopy images for mitochondrial morphology and statistical analysis of mitochondrial area (n ≥ 20) in Tipe2+/+ or Tipe2-/- macrophages. Scale bars, 500 nm. b Representative confocal imaging of immunofluorescence for mitochondria (MitoTracker, red; inset, grayscale images) and Drp-1 (green) in Tipe2+/+ or Tipe2-/- macrophages. Nuclei (DAPI, blue). Scale bars, 3 μm. c Representative confocal imaging of mitochondria (MitoTracker, red; right, binary images) in Tipe2+/+ or Tipe2-/- macrophages after 18 h treatment with or without 50 μM Mdivi-1. Nuclei (DAPI, blue). Scale bars, 2 μm. d Representative confocal imaging of intracellular Ca2+ (Fluo-4 AM, green) in Tipe2+/+ or Tipe2-/- macrophages. Scale bars, 50 μm. e, f Representative immunoblots for indicated proteins in Tipe2+/+ or Tipe2-/- macrophages (e), or post 2 h treatment with or without 10 μM BAPTA (f). g,h Representative confocal imaging of mitochondria (MitoTracker, red; bottom, binary images and skeletonized branches) in Tipe2-/- or Tipe2+/+ macrophages after 2 h treatment with or without 10 μM BAPTA (g), 50 μM 2-APB (h), respectively. Scale bars, 5 μm. i, Immunoblots for indicated proteins in Tipe2+/+ or Tipe2-/- macrophages post 2 h treatment with or without 50 μM 2-APB. j Representative confocal imaging of immunofluorescence for TIPE2 (green) and IP3R (red) in Tipe2+/+ macrophages. Nuclei (DAPI, gray). Scale bars, 10 μm. k Representative blots for IP3R and TIPE2 proteins in Tipe2+/+ macrophage lysates immunoprecipitated by antibodies against TIPE2 or IP3R. l Representative confocal imaging of immunofluorescence for F-actin (green) and IP3R (red) in Tipe2+/+ or Tipe2-/- macrophages. Nuclei (DAPI, gray). Scale bars, 5 μm. Data are representative of at least two independent experiments. ***P < 0.001 determined by two-tailed student’s t-test (a).
