Lock-hTf–endosomes interact longer with mitochondria. The duration of each individual hTf- or lock-hTf–endosome–mitochondrion kiss phase was calculated by multiplying the number of consecutive frames in which they were seen to be interacting (DT = 0) by the known interval (139 ms) of time-lapse acquisition. (A) Percent distribution of the duration of kiss events between hTf-endosomes (n = 311 events) and lock-hTf–endosomes (n = 603 events) with mitochondria. (B) Percent cumulative distribution of duration of kiss events with a logarithmic equation trend line to fit data points. The half-life duration of kiss events by hTf-endosomes (black dotted line) is 216 ms (y = 23.544ln(x) − 76.472), whereas for the lock-hTf–endosomes (gray dotted line), it is 416 ms (y = 22.877ln(x) − 87.928).