Five MAPs reconstitute all phases of microtubule dynamics in vitro. (A) Diagram depicting the phases of microtubule dynamic instability, including polymerization (growth), pause, and depolymerization (shrinkage). Three proteins, XMAP215^Msps, CLASP^Mast/Orbit, and Kinesin-13^Klp10A, promote polymerization, pause, and depolymerization, respectively. Although these regulators engage the microtubule directly, EB1 and Sentin recruit CLASP^Mast/Orbit and XMAP215^Msps to polymerizing microtubule plus ends and affect their activity. (B) Microtubule dynamics diamond graphs showing in vitro microtubule behavior without (left) and with (right) Plk1^Polo treatment. The black diamond graph at left is overlaid on the purple graph at right and shown in dark gray for comparison.