Actiinisäikeisiin

Actiinisäikeisiin, commonly referred to as actin filaments or microfilaments, are essential components of the cytoskeleton found in eukaryotic cells. They are thin, flexible protein filaments, approximately 7 nanometers in diameter, primarily composed of the globular protein actin. Actin monomers, known as G-actin, polymerize in a head-to-tail manner to form a double helical filament called F-actin. This polymerization process is dynamic, meaning filaments can rapidly assemble and disassemble, a characteristic crucial for cellular functions.

Actin filaments play a vital role in maintaining cell shape and providing structural support. They are particularly abundant at the cell periphery, forming a dynamic network that resists external forces and helps define the cell's architecture. Beyond structural support, actin filaments are deeply involved in cell movement. They form the basis of pseudopods, allowing cells to crawl, and are integral to muscle contraction, where their interaction with myosin filaments generates force. Furthermore, actin filaments are involved in intracellular transport, vesicle trafficking, and cytokinesis, the process of cell division. Their dynamic nature allows for rapid reorganization in response to cellular signals, enabling cells to adapt and respond to their environment.