Movie S2.

Transfer of calcium at mitochondria-lysosome contact sites in live HeLa cells. Example time-lapse video of transfer of calcium (white arrow) to mitochondria following lysosomal TRPML1 activation with ML-SA1 (31.25 μM) at mitochondria-lysosome contacts in live HeLa cells transfected with mitochondria matrix-targeted calcium sensor, Mito-R-GECO1, and lysosome marker, lamp1-mGFP, corresponding to Fig. 2B. Scale bar, 1 μm.