You are interested in studying the secretion of the growth factor bdnf by neurons, and you want to track bdnf from its synthesis on ribosomes through secretion by cells. you hypothesize that (i) bdnf transits through the endomembrane system; (ii) is packaged into secretory vesicles and actively transported to the plasma membrane; and (iii) bdnf-containing vesicles fuse with the membrane when local ca2+ concentrations increase. propose an experiment that addresses each part of this hypothesis. in doing so, specifically state (i) the organelles of the endomembrane system that you would expect bdnf to travel through; (ii) the type of vesicle into which bdnf is packaged, as well as any motor protein(s) and/or cytoskeletal structures required to the bdnf-containing vesicle to the plasma membrane; and (iii) describe the ca2+-dependent mechanism through which you think vesicular fusion is regulated. for each part of the hypothesis, note two proteins that you might target (either by pharmacological or genetic approaches) to determine whether those processes are required for secretion of bdnf. state the expected outcome of your proposed experiment for each part of the hypothesis, based on targeting these proteins.