Suppose you discover a novel process in a little-studied cell type in which application of a chemical causes an unknown organelle to undergo energy-dependent movement from near the MTOC to the plasma membrane. To probe the cytoskeletal elements required for this movement you add an actin depolymerizing drug latrunculin A. This drug does not affect the initial movement of the organelle away from the MTOC, however the organelle stops before reaching the plasma membrane. You next try the microtubule depolymerizing drug colchicine. This drug prevents any movement of the organelle away from the MTOC in response the chemical stimulus. 1. What do these results tell you about the identity of the cytoskeletal elements involved and the identity of the required motor proteins over the course of movement?
2. Predict the result you would get if you added both latrunculin A and colchicine at the same time. Would the resulting phenotype be a combination of adding each drug alone, would one or the other drug’s effects predominate, or would they cancel each other out? Why?