Filopodia

Filopodia are slender cytoplasmic projections that extend beyond the leading edge of lamellipodia in migrating cells. They are involved in a variety of processes including cell motility, cell-cell interactions, and cell-matrix interactions.

Structure

Filopodia are composed of parallel bundles of actin filaments which are cross-linked by actin-bundling proteins. The actin filaments are oriented such that their barbed (plus) ends are distal to the cell body. The filopodial tip complex, which is located at the distal end of the filopodium, is thought to regulate actin polymerization and depolymerization, and thus filopodial protrusion and retraction.

Function

Filopodia have been implicated in a variety of cellular processes. They are involved in cell motility, where they are thought to act as "sensory antennae" that probe the environment for directional cues. They also play a role in cell-cell interactions, such as in the formation of synapses in neurons, and in cell-matrix interactions, where they mediate adhesion to the extracellular matrix.

Clinical significance

Abnormalities in filopodia formation and function have been linked to a number of diseases, including cancer and neurological disorders. For example, increased filopodia formation has been observed in cancer cells, and is thought to contribute to their invasive behavior. On the other hand, defects in filopodia formation have been implicated in neurological disorders such as Fragile X syndrome and Autism spectrum disorder.

See also

• Lamellipodia
• Microvilli
• Pseudopodia

References

Filopodia Resources
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