Appearances aside, the image above, produced by Tom Deerinck at the National Center for Microscopy and Imaging Research at UC San Diego, does not actually depict cells in flames.
Rather, the red, fire-like projections are filopodia – microscopic filamentous bundles that serve multiple cellular functions. For example, they act as sensory antennae, probing the cell’s surrounding microenvironment. Motile or migratory cells commonly sport filopodia, which aid in their movement. Fibroblasts use filopodia to migrate to wounds and close them. Filopodia also help direct the growth of dendrites in neurons.
Filopodia are even used by some bacteria to move between cells, helping them evade the host immune system.