A Polarised Population of Dynamic Microtubules Mediates Homeostatic Length Control in Animal Cells
Figure 9
Testing the model of microtubule-based cell length homeostasis.
(A and B) Model cell length dynamics (A) and numbers of microtubules (MT) interacting with the cell margin (B) were analysed as the microtubule polymerisation rate, vg, was changed by a factor of 0.75 (orange) or 0.5 (red). (Nm = 11 and α = 8; other parameters were fixed.) (C–E) As a test of this model, 40 nM colcemid (D) or an equivalent volume of DMSO (E) was added to HeLa cells on lines of varying widths (3–10 µm, 11–15 µm, 16–20 µm, 21–25 µm, and 26–35 µm) at steady state, and average cell length was measured. An HeLa cell spreading on a fibronectin line is shown (C) before and after treatment with 40 nM colcemid (at 120 min, indicated by orange arrow). The green dotted line indicates expected length without perturbation. Orange dotted line indicates measured cell length. Scale bar = 10 µm. Error bars denote upper and lower box plot quartiles.