We aim to understand the intracellular signal pathway and extracellular factors regulating Drp1 phosphorylation and mitochondrial morphology and function in cardiomyocytes. * P < 0.05, one-tailed Student’s t-test.Loss of the mitochondrial fission enzyme dynamin-related protein 1 (Drp1) in cardiomyocytes results in energy shortage and heart failure. h, Representative time-lapse frames of peroxisomal fission events in wild-type and dynamin triple-knockout cells, co-transfected with the peroxisomal marker Ub-RFP-SKL and DRP1–GFP ( n = 21 cells). f, g, Respective peroxisomal morphology of cells in e, as in c and d ( n = 30 cells each). e, PMP70 immunofluorescence of wild-type and dynamin triple-knockout cells co-transfected with PEX11β and DRP1 ( n = 30 cells each). c, d, Respective quantification of peroxisomal morphology by number of peroxisomes per ROI ( c) and peroxisomal area per ROI ( d) for the cells in b ( n = 30 cells each). b, PMP70 immunofluorescence of wild-type mock mouse embryonic fibroblasts and wild-type fibroblasts transfected with PEX11β and DRP1 plasmids ( n = 30 cells each). PEX11β oligomerizes at the peroxisome division site, promoting peroxisomal membrane elongation, enrichment of fission factors such as FIS1 and MFF, and recruitment of DRP1 at the division site for the scission event. Scale bars, 10 µm ( e, k, s) and 2 µm ( u).Ī, Schematic model of peroxisomal fission induction by PEX11β and DRP1 overexpression (adapted from ref. u, Representative time-lapse of a mitochondrial fission event in scrambled and DNM2-knockdown HeLa cells expressing Mito-GFP ( n = 15 cells each). t, Respective mitochondrial area of cells in s ( n = 25 cells each). s, TOM20 immunofluorescence of HeLa cells transfected with scrambled and DNM2 DsiRNA ( n = 25 cells each). q, r, Immunoblot ( q) and quantification ( r) of DNM2 in scrambled and DNM2-knockdown HeLa cells ( n = 3). o, p, Immunoblot and quantification analyses of mitochondrial fission ( o) and fusion ( p) proteins of DNM2 in fibroblasts transfected with scrambled and DNM2 DsiRNA ( n = 3). l– n, Respective mitochondrial morphology analysis of cells in k ( n = 30 cells each). k, TOM20 immunofluorescence of fibroblasts transfected with scrambled and DNM2 DsiRNA ( n = 30 cells each). i, j, Immunoblot ( i) and quantification ( j) of DNM2 in scrambled and DNM2-knockdown fibroblasts ( n = 3). f– h, Respective mitochondrial morphology analysis of the cells in e, as in Fig. e, TOM20 immunofluorescence of wild-type and dynamin triple-knockout cells ( n = 30 cells each). e– h, Mitochondrial fission occurs independently of DNM1, DNM2 and DNM3. c, d, Representative immunoblot ( c) and quantification ( d) of expression levels of DNM1–DNM3 ( n = 3). 9, 5239 (2018).Ī, b, Cre- loxP recombination system ( a) and protocol to obtain dynamin triple-knockout and DRP1-knockdown cells ( b). Dynamin-related protein 1 has membrane constricting and severing abilities sufficient for mitochondrial and peroxisomal fission. Cryo-EM Studies of Drp1 reveal cardiolipin interactions that activate the helical oligomer. Quantitation of mitochondrial dynamics by photolabeling of individual organelles shows that mitochondrial fusion is blocked during the Bax activation phase of apoptosis. Mitochondrial fission factor Drp1 is essential for embryonic development and synapse formation in mice. Erk2 phosphorylation of Drp1 promotes mitochondrial fission and MAPK-driven tumor growth. Mff is an essential factor for mitochondrial recruitment of Drp1 during mitochondrial fission in mammalian cells. Division versus fusion: Dnm1p and Fzo1p antagonistically regulate mitochondrial shape. Proliferation and fission of peroxisomes-an update. Dynamin triple knockout cells reveal off target effects of commonly used dynamin inhibitors. Multiple dynamin family members collaborate to drive mitochondrial division. Actin filaments target the oligomeric maturation of the dynamin GTPase Drp1 to mitochondrial fission sites. Structural basis of mitochondrial receptor binding and constriction by DRP1. Dephosphorylation by calcineurin regulates translocation of Drp1 to mitochondria. The dynamin-related GTPase Dnm1 regulates mitochondrial fission in yeast.