FIGURE 8:

Lipid requirements for the predicted geometric instabilities. (a) The initial geometry and the required PE concentrations.  For a tubule radius of 250 nm and PE lipid radius of curvature of 3 nm (Zimmerberg and Kozlov, 2006), the required (asymmetric) concentration is 1.2% in the hemispherical domain and 0.6% in the cylindrical domain. (b) The geometry before actin–lipid induced instability and the required PE concentrations. Only 0.20% change in the PE concentration is required in the domain adjacent to actin to trigger the instability. This increase is accompanied by a concomitant decrease in the PE concentration by 0.1% in the cylindrical domain. (c) The geometry before Drp1–lipid induced instability and the required PE concentrations. Only 0.96% change in the PE concentration is required in the domain adjacent to Drp1 to trigger the instability. This increase is accompanied by a concomitant decrease in the PE concentration by 0.41% in the cylindrical domain. These small changes in the areal concentration are sufficient to achieve extreme necking. It is important to note that the required PE lipids into the central blue domains can come from the nearby yellow domains and are not required to come from the blue domains at the poles. Thus, local rearrangement by ∼1.5% adjacent to the protein domain is enough to generate necking conducive for fission.