Fig. 6

Mul1 deficiency reduces mitochondrial Ca²⁺ uptake from the ER. a, b Representative traces and quantitative analysis of the average maximal Ca²⁺ peak showing impaired mitochondrial Ca²⁺ uptake from the ER in Mul1-deficient neurons. Cortical neurons were co-transfected at DIV7-8 with pcDNA-4mtD3cpv and Flag or Flag-Mul1ΔRing, followed by live imaging at DIV10-11. The emission spectra of the ratiometric probe (525 nm/458 nm) were obtained by exciting 405 nm following stimulation with 10 μM histamine. c, d Reduced Ca²⁺ load in both axonal and dendritic mitochondria in Mul1-deficient neurons. The pseudo colors cyan (458 nm) and green (525 nm) represent the emission spectra of the ratiometric probe when excited with 405 nm. The images were captured from dendritic and axonal compartments as indicated. The mitochondrial Ca²⁺ load was expressed as a ratio (525 nm/458 nm). Note that expressing Mul1ΔRing significantly reduces the ratio while expressing Mul1 enhances the ratio. Data were analyzed from 2 to 3 live neurons per field with 4 fields per experiment (b), or total number of fixed neurons indicated in the bars (d) in three experiments and expressed as mean ± s.e.m. Unpaired Student’s t-test was used for comparing two groups and Ordinary one-way ANOVA with Dunnett multiple comparison test for multiple comparisons. Scale Bars: 10 μm