filopodium

Definition

Target type: cellularcomponent

Thin, stiff, actin-based protrusion extended by the leading edge of a motile cell such as a crawling fibroblast or amoeba, or an axonal or dendritic growth cone, or a dendritic shaft. [GOC:mah, GOC:pr, ISBN:0815316194]

Filopodia are thin, finger-like projections of the plasma membrane that extend from the cell surface. They are typically 100-200 nm in diameter and can reach up to 10 µm in length. Filopodia are highly dynamic structures that can rapidly extend and retract, allowing cells to sense their environment and interact with other cells or surfaces.

The core of a filopodium is composed of a bundle of actin filaments, which are arranged in a parallel fashion. This bundle of actin filaments is known as the filopodial core or the actin core. The actin filaments are cross-linked by various actin-binding proteins, including fascin, fimbrin, and α-actinin, which help to maintain the structure of the filopodium.

The plasma membrane of a filopodium is also enriched in various proteins, including receptors, adhesion molecules, and signaling molecules. These proteins allow the filopodium to interact with its environment and participate in various cellular processes, such as cell migration, adhesion, and signaling.

In addition to the actin core and the plasma membrane, filopodia also contain other cellular components, including:

* **Adhesive proteins:** These proteins, such as integrins and cadherins, allow the filopodium to adhere to other cells or surfaces.
* **Signaling molecules:** These molecules, such as growth factors and chemokines, can be transported to the filopodial tip, where they can interact with other cells or trigger signaling pathways.
* **Enzymes:** These enzymes, such as kinases and phosphatases, can modify the activity of other proteins in the filopodium, regulating its function.
* **Motor proteins:** These proteins, such as myosin, can move along the actin filaments, contributing to the dynamic extension and retraction of filopodia.

The specific composition of a filopodium can vary depending on the type of cell and the cellular context. However, all filopodia share the common features of a core of actin filaments, a plasma membrane enriched in proteins, and a dynamic structure that allows them to explore and interact with their environment.'
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Proteins (19)

Compounds (1,026)