Macrophage chasing bacteria
Cell migration is a necessary process in development and maintenance of our bodies. As we mentioned before, growing axons need to migrate through the spinal cord and form the correct connections. Migration is also important for immune cells called neutrophils. Neutrophils are an important line of defense in our immune system and can sense foreign pathogens. They catch and engulf these invaders and eventually destroy these potentially harmful microbes. Click here to watch a video of a neutrophil chasing a bacteria.
Wound Healing
Wound healing is the process by which body tissue, most commonly the skin, repairs itself after an injury. During this process, cells called fibroblasts divide and migrate to help repair the damage. Again, actin facilitates the movement of migrating fibroblasts to patch up your skin after a cut or abrasion.
Here we see a time lapse image of a monolayer (1 cell thick) of epithelial cells. In this experiment, a “scratch” is performed down the middle of the plate and forms an empty space. The two separated groups of epithelial cells respond by migrating towards each other. This methods is commonly used to reveal mechanisms of cell motility(CIL:44512).
Here we observe the protruding lamellipodia from zebrafish epidermal cells. Using differential interference contrast microscopy, we are able to observe a small structure in 3 dimensions. Actin filaments can be seen forming at the tip of the moving structure (CIL37333).
Despite it being a necessary function, cell migration may not always be a good thing. If a cell accumulates mutations in the DNA, it can cause a cell that is normally stationary to migrate. This process is called metastasis, and is a common trait of cancer cells. Cells that migrate and start to divide uncontrollably can eventually form tumors. These mutations of the DNA usually influence the regulation of the cytoskeleton.