Fig. 4. Quantification of Membrane Fission and Condensation.

A) A COS-7 cell expressing endoΔSH3-FRB-GFP and Synj1-Ptase-FKBP-RFP is shown before and after rapamycin treatment. Using ImageJ, lines were drawn to follow the endophiilin-induced tubules before application of rapamycin. The evolution of these tubules were then followed after rapamycin treatment to select the broken tubules resulting from the recruitment of Synj1-Ptase-FKBP-RFP to these tubules. The final picture was used to draw the resulting broken tubules. B) The same method was used to draw tubules for a COS-7 cell expressing endoΔSH3-FRB-GFP and Synj1-PtaseD730A-FKBP-RFP before and after rapamycin treatment. C) Quantification of tubule length of the cells shown in A) and B) using ImageJ shows the dramatic decrease in total tubule length in the cell expressing wildtype Synj1-Ptase after rapamycin treatment in comparison to the small decrease experienced by the cell expressing the catalytically inactive Synj1-PtaseD730A. D) Comparison of the % reduction in tubule length in cells expressing either WT or catalytically inactive Synj1-Ptase with a n=24 for WT or n=9 for D730A. Data are represented as mean ± SEM. *** p < 0.0001. [Panel E is reprinted from Developmental Cell, Vol. 20, Chang-Ileto, B., Frere, S.G., Chan, R.B., Voronov, S.V., Roux, A., and Di Paolo, G., Synaptojanin 1-mediated PI(4,5)P₂ hydrolysis is modulated by membrane curvature and facilitates membrane fission, Pages No. 206–218, copyright 2011, with permission from Elsevier.]