Question

The locomotion of fibroblasts in culture is immediately halted by the drug cytochalasin, whereas colchicine causes fibroblasts to cease to move directionally and to begin extending lamellipodia in seemingly random directions. Injection of anti-vimentin has no obvious effect on fibroblast migration. What do these results suggest about the role of the cytoskeleton in fibroblast movement?                                              

Answer 1

• Cell movement is a multi step process which is facilitated by spatial polarity and formation of membrane protrusions in the direction of cell movement. The direction and movement of fibroblasts is regulated by dynamics of Cytoskeletal proteins such as actin, microtubules and intermediate filaments.
• Cell movement begins in response to signal from polyemerizing actin filaments followed by direction provided by microtubules and intermediate filaments.
• Cytochalasin inhibits actin polymerization and interaction of actin with motor protein (myosin), as locomotion is immediately halted after cytochalasin treatment, primary role of actin in fibroblast movement is depicted.
• Colchicine inhibits assembly and disassembly of microtubules, as colchicine treatment caeses directionality of lamellipodia therefore it can be concluded that microtubules are responsible for providing the direction of movement of fibroblasts i.e. the direction in which lamellipodia formation proceeds, therefore colchicine treatment results in lamellipodia extension in random directions.
• Vimentin also provides directionality to the fibroblast movement, there is no much effect of anti vimentin drug treatment on fibroblast movement as this function can be replaced by microtubules.