Aster-B deficiency reduces mitochondrial cholesterol content. (A–B) Total cholesterol level (A) and mitochondrial cholesterol level (B) in vector control (VC) and Aster-B knockout (KO) cells. Cells in normal culture condition (CM), treated with MCD (MCD) or incubated with 50 μM of cholesterol after MCD treatment (CHOL). n = 3. ∗p < 0.05, ∗∗p < 0.01 by two-way ANOVA. (C) The ratio of mitochondrial cholesterol to the total cholesterol in VC and Aster-B KO cells. n = 3. ∗p < 0.05, ∗∗p < 0.01 by two-way ANOVA. (D–G) Total cholesterol levels (D) and cholesterol levels in pure mitochondria (E), mitochondrial-associated membrane (MAM) (F) and microsomes (G) in VC and Aster-B KO cells. Cells were treated with MCD (-CHOL) or pemeabilized by digitonin after MCD treatment and re-incubated with 50 μM of cholesterol (+CHOL). n = 3. ∗p < 0.05, ∗∗∗p < 0.001 by two-way ANOVA.