Spatacsin regulates the dynamics of acidic tubular lysosomes.

(A). Live imaging of lysosomes stained with various markers in Spg11+/+ MEFs. Note that tubular lysosomes (white arrows) were positive for Lamp1, 10 kDa Dextran-Texas Red (TR), Lysotracker green, as well as DQ-BSA green, indicating that they are acidic and catalytically active compartments. Scale bar: 5 μm. (B) Quantification of the number of tubular lysosomes in Spg11+/+ and Spg11−/− MEFs using the fluorescent markers DQ-BSA, Lysotracker, or Dextran. Superplot: means and SEM, N > 40 cells from 3 independent experiments. Paired t tests on the means. (C) Quantification of the proportion of lysosomes with an average speed > 0.3 μm/s according to their shape in wild-type MEFs. Mean and SEM, paired t test. (D) Quantification of the average speed of round lysosomes in Spg11+/+ and Spg11−/− MEFs. Superplot: means and SEM, N > 87 cells from 4 independent experiments. Paired t test on the means. The raw data underlying panels B, C, and D can be found in S1 Data file. (PDF)