Filopodiin

Filopodiin is a term used in cell biology to describe dynamic, slender, finger-like projections that extend from the cell surface. These structures are a type of cell protrusion, distinct from broader lamellipodia. Filopodia are primarily composed of actin filaments, which are bundled together by proteins like fascin and fimbrin. The extension and retraction of filopodia are driven by the polymerization and depolymerization of actin.

The formation of filopodia is often triggered by external signals, such as growth factors or cues from the extracellular matrix. They are believed to play crucial roles in various cellular processes. These include cell migration, where filopodia can act as scouts, sensing the environment and guiding the direction of movement. They are also involved in cell adhesion, making contact with other cells or the substratum. In developmental biology, filopodia are important for tissue morphogenesis and cell-cell communication.

Research has shown that filopodia are highly dynamic, with individual projections extending and retracting over timescales of seconds to minutes. Their structure and behavior can vary depending on the cell type and its environment. The precise mechanisms by which filopodia are regulated, including their initiation, elongation, and stabilization, are areas of ongoing investigation. Understanding filopodia is key to comprehending fundamental aspects of cell behavior, including disease processes like cancer metastasis.