Figure 8. The MTM1-desmin complex is associated with mitochondria and is involved in mitochondrial dynamics/motility.

(A) Subcellular fractionation of muscles from WT or Mtm1-KO mice (lanes labeled 1 and 2, respectively) showed accumulation of desmin in the mitochondrial fraction in Mtm1-depleted muscle along with the mitochondrial markers prohibitin and cytochrome c. The cytosolic protein HSP70 served as a control. (B) MTM1, desmin, and cytochrome c levels in mitochondrial fractions in WT and Mtm1-KO muscle relative to the mitochondrial protein (prohibitin). Data correlated from 2 independent experiments (3 mice per group; 2 tibialis anterior muscles per mouse). *P ≤ 0.05. (C) Number of motile mitochondria in the peripheral and perinuclear region of scramble and Mtm1-KD myoblasts. *P ≤ 0.05. (D) Mean velocity of mitochondria in scramble versus Mtm1-KD myoblasts. (C and D) N, number of total cells monitored; n, number of mitochondria scored. (E) Spot plot depicting velocity of individual mitochondria and their cellular position in relation to nucleus (0 μm) in scramble and Mtm1-KD myoblasts. Data correlated from 2 independent experiments. (F) Depletion of MTM1 in muscle did not affect the plectin-desmin interaction. Mitochondrial and microsomal fractions from WT and Mtm1-KO muscles were subjected to IP with an anti-plectin antibody and revealed by anti-desmin antibody. Prohibitin and β-DG were used as mitochondrial and microsomal markers, respectively. Data were correlated from 2 independent experiments. *P ≤ 0.05.