Figure 3.

Multiple motors haul lipid droplets in Drosophila embryos. (A) The position of a lipid droplet pulled by kinesin motors in the optical trap shows a stall that is followed by another motor engaging to the microtubule and pulling the droplet further into the trap at ∼1.5 s. The two motors stall again at about twice the force of the single motor. (B) A histogram of kinesin stall forces of lipid droplets measured in vivo shows peaks at multiples of ∼2.6 pN indicating the action of multiple motors. No constraints on peak position were used in the Gaussian fits. Statistical analysis to confirm the position of the peaks can be found in the Supporting Material.