Figure 5.

Phosphorylation at region C^Spc34p uniquely reduces stability under constant force while preserving rupture strength. Rupture strengths from Figs. 1 and 2 are replotted against attachment lifetimes measured for the same couplers on growing microtubule tips under constant force (1.5–3.5 pN). Data were obtained using beads coated with either wild-type Ndc80 complexes (salmon) or mutant Ndc80 complexes with disruptions in region A^Ndc80p (light purple), B^Ndc80p (lime green), or C^Ndc80p (turquoise) in the presence of unphosphorylated Dam1 complexes, or using beads coated with wild-type Ndc80 complexes in the presence of either phospho-deficient 6A Dam1 complexes (black) or Dam1 complexes phosphorylated at region A^Dam1p (dark purple), B^Ask1p (dark green), or C^Spc34p (blue).