Microfilamenten

Microfilaments, also known as actin filaments, are dynamic protein structures found in the cytoplasm of eukaryotic cells. They are composed of a polymer of actin protein subunits arranged in a helical filament. These filaments are among the thinnest components of the cell's cytoskeleton, typically measuring about 7 nanometers in diameter. Microfilaments play a crucial role in maintaining cell shape, providing mechanical support, and enabling cell movement.

One of the primary functions of microfilaments is to contribute to cell structure. They form a network beneath the plasma membrane, known as the cell cortex, which helps to resist mechanical stress and maintain the cell's overall shape. In some specialized cells, like muscle cells, microfilaments are organized into contractile structures that are essential for movement.

Microfilaments are also intimately involved in cell motility. They can assemble and disassemble rapidly, allowing cells to extend protrusions like pseudopods or lamellipodia, which are used for crawling and engulfing particles. This dynamic assembly and disassembly is regulated by a variety of actin-binding proteins. Furthermore, microfilaments are involved in intracellular transport, acting as tracks along which motor proteins can move organelles and vesicles. Their rapid assembly and disassembly, coupled with their interaction with motor proteins, makes them indispensable for a wide range of cellular processes.