Figure 4: Tension on the linker inhibits nucleotide-dependent release of dynein from MTs.

(a) Dynein monomers are attached to a polystyrene bead either through the N terminus of the linker via a GFP-antibody linkage, or through the C terminus of the ring via a 74-bp long DNA tether (not to scale). (b) A representative trace showing bead position (blue) and trap position (green). (c) Force-dependent release rates of dynein monomers when the trapped bead is attached to the N-terminal linker domain. The distribution of the forward and backward release rates are unaffected by the presence (red, n=3,003) and absence (blue, n=2,335) of ATP. Shaded regions indicate 95% confidence intervals. Inset: a representative example of the distribution of measured MT-bound times at 0.94 pN average force towards the MT minus-end at 1 mM ATP. Black curve represents maximum likelihood fit to the dwell time histogram. (d) Force-dependent release rates when dynein is pulled through the C terminus. The rate is similar to the N-terminal attachment case (dotted black line) in the absence of ATP (blue, n=1,105), but increases several fold in the presence of 2 mM ATP (red, n=1,652).