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Endosome – mitochondria interactions are modulated by iron release from transferrin

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ABSTRACT

Using superresolution and quantitative fluorescence microscopy, Das et al. have revealed that iron-transferrin–containing endosomes directly interact with mitochondria, facilitating iron transfer in epithelial cells. Their findings further enrich the repertoire of organelle–organelle direct interactions to accomplish a functional significance.

No MeSH data available.


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).
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fig7: 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).

Mentions: To further address the impact of perturbed endosomal cargo on the dynamics of endosome–mitochondria interactions, we compared the duration of kiss interactions between all detected hTf- and lock-hTf–endosomes with mitochondria. The duration (milliseconds) of each kiss phase between each individual hTf- and lock-hTf–endosome with mitochondria was calculated from the known interval of acquired time-lapse (139 ms) and the number of consecutive image frames that were detected proximal to a mitochondrion (cross-verified by DT = 0). Only completely detected kiss and run events defined by one or more frames of kiss flanked before and after by at least one frame each of noninteraction (DT > 0) with mitochondria were considered for analysis. Although the majority of the detected endosome–mitochondria interactions by both the hTf- and lock-hTf–endosomes were observed to last for durations of <0.5 s, an increased number of longer interactions was observed in the case of the lock-hTf–endosomes (Fig. 7 A). To resolve this further, we plotted the percent cumulative distribution of the duration of interactions and fitted the data points using a logarithmic equation trend line (Fig. 7 B). We found that the half-life of duration of kiss events by hTf-endosomes (Fig. 7 B, black dotted line) derived from the trend line equation y = 23.544ln(x) − 76.472 is 216 ms, whereas the half-life of duration of kiss events by lock-hTf–endosomes (Fig. 7 B, gray dotted line) derived from the trend line equation y = 22.877ln(x) − 87.928 is 416 ms. The substantial increase in the half-life of lock-hTf–endosomal kiss duration suggests that blocking intraluminal iron release from the Tf–TfR complex and the subsequent changes in the Tf–TfR conformation prolong Tf-endosome–mitochondria kiss interactions.


Endosome – mitochondria interactions are modulated by iron release from transferrin
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).
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fig7: 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).
Mentions: To further address the impact of perturbed endosomal cargo on the dynamics of endosome–mitochondria interactions, we compared the duration of kiss interactions between all detected hTf- and lock-hTf–endosomes with mitochondria. The duration (milliseconds) of each kiss phase between each individual hTf- and lock-hTf–endosome with mitochondria was calculated from the known interval of acquired time-lapse (139 ms) and the number of consecutive image frames that were detected proximal to a mitochondrion (cross-verified by DT = 0). Only completely detected kiss and run events defined by one or more frames of kiss flanked before and after by at least one frame each of noninteraction (DT > 0) with mitochondria were considered for analysis. Although the majority of the detected endosome–mitochondria interactions by both the hTf- and lock-hTf–endosomes were observed to last for durations of <0.5 s, an increased number of longer interactions was observed in the case of the lock-hTf–endosomes (Fig. 7 A). To resolve this further, we plotted the percent cumulative distribution of the duration of interactions and fitted the data points using a logarithmic equation trend line (Fig. 7 B). We found that the half-life of duration of kiss events by hTf-endosomes (Fig. 7 B, black dotted line) derived from the trend line equation y = 23.544ln(x) − 76.472 is 216 ms, whereas the half-life of duration of kiss events by lock-hTf–endosomes (Fig. 7 B, gray dotted line) derived from the trend line equation y = 22.877ln(x) − 87.928 is 416 ms. The substantial increase in the half-life of lock-hTf–endosomal kiss duration suggests that blocking intraluminal iron release from the Tf–TfR complex and the subsequent changes in the Tf–TfR conformation prolong Tf-endosome–mitochondria kiss interactions.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Using superresolution and quantitative fluorescence microscopy, Das et al. have revealed that iron-transferrin&ndash;containing endosomes directly interact with mitochondria, facilitating iron transfer in epithelial cells. Their findings further enrich the repertoire of organelle&ndash;organelle direct interactions to accomplish a functional significance.

No MeSH data available.