Question

13-3 Cytoskeletal Studies. Described here are the results of several recent studies on the proteins of the cytoskeleton. In each case, state the conclusion(s) that can be drawn from the findings.

(c)A macrophage cell can ‘crawl’ towards foreign pathogens and inactivate them. A diver came in contact with Latrunculia magnifica via an open wound. If the diver is exposed to harmful
bacteria at the same time, how will the macrophages in the diver’s blood respond?

13-6 Spongy Actin. You are interested in the detailed effects of cytochalasin D on microfilaments over time. Based on what you know about the molecular mechanism of action of cytochalasins, describe what happens to MFs in cells treated with the drug. In particular, explain why existing actin polymers eventually depolymerize.

Answer 1

Ans c) When the diver dives in the open wound comes in contact with Latrunculia magnifica which is a toxic finger sponge and it is extremely toxic. At the same time if the diver is also impacted by harmful bacteria or exposed to it, there will be immediate inactivation of the immune system. It will lead to increase in production of the macrophages that will crawl towards the bacteria and engulf it. The macrophages however will be confused on where to make the first move as the diver wound is also hit by toxins.

Ans 13-6) The effect of the cytochalasin D on the cells is due to the strong interaction of the drug with the actin filament which is a part of cytoskeletal networks and secondary cellular response. They bind to fast growing ends of the microfilaments and it leads to assembly and disassembly of the individual actin units and it helps in capping the newly synthesized actin filaments. The existing actin polymers eventually depolymerize because the drug tends to weaken the network as the cytochalasin D rapidly grows the ends.