Schöneberget al.,Science 362 , 1423–1428 (2018) 21 December 2018 5of6
Atube
force -f[pN] 020010-10B scissiontube
radius [nm]3010200tube radius
predictionforce
prediction-100 0 100 200 300 400 500 600 7000 100 200 300 400 -100^01002003004005006007000100200 300 400force
predictiontube
force -f[pN] 0tube
radius [nm]4002020010tube radius
predictionscission1100EGtime [s]1membrane intensity [AU] 0time [s]10tube
intensity [AU]-100 0 100 200 300 400 500 600 700-100 0 100 200 300 400 500 600 700FHmembrane Snf7 Vps4
membrane intensity [AU]tube
intensity [AU]
0100200 300 400membrane Snf7 Vps40100200 300 400I101
fl. int. 0start of experiment 0s end of experiment 425sJ
-20 sC D150s 420s 450s
post scissionO040040force - f 0 [pN] predicted030030radius [nm] measuredradius [nm] predictedr = 0.82 r = 0.892020force - f[pN] 0measured1515tube
force -f[pN] 00350.21.0norm. tube radius [nm]t = 0s scission
norm. timet = 0s scission
norm. time t = 0s scission
norm. timet = 0s scission
norm. timeK L M N06norm. tube intensity1234506norm. tube intensity12345Snf7 Vps4Fig. 4. ESCRT membrane scission is mediated by tube constriction.(Aand
B) Force profiles of the same events shown in Fig. 3 were normalized to their
respective baseline tube holding force,f 0. ATP released by UV uncaging led to a rise in
force and eventually scission (indicated by the sharp drop of force at the end of the
trace, 2 of 17). (CandD) Simultaneous observation of the tube radius revealed a
continuous radius decrease. Force and radius plots are overlaid with predictions from
the Helfrich model for a tube of unchanged bending rigidity under constant tension
(dashed orange lines) (see methods description in the supplementary material).
(EandF) Normalized and bleaching-corrected fluorescence intensity profiles of the
scission events for the tube in the three fluorescence channels (Snf7, green; Vps4,
cyan; membrane, red). SDs are shown as shaded areas. After ATP uncaging, the
tube membrane fluorescence intensity decreased, while the tube Snf7 and
Vps4 intensities increased. (GandH) The GUV membrane fluorescence intensity
profile over the time course of the scission event was essentially constant and showed no correlation with the force (Snf7, green; Vps4, cyan; membrane,
red). SDs are shown as shaded areas. (I) Fluorescence intensity profiles of the GUV membrane at the start and at the end of the scission trace. No
increase in protein fluorescence on the membrane was detected. (J) GUV aspiration projection at the beginning, middle, and end of the scission trace,
showing essentially no change. (KtoN) Averages (N= 17) ± SD of the force, radius, and tube fluorescence showed a consistent force rise, radius decrease,
and fluorescence increase in the tube. (O) Correlation (r) between experiments and prediction for radius and force (N= 17).
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