Aktínþráðarnir

Aktínþráðarnir, also known as actin filaments, are essential components of the cytoskeleton in eukaryotic cells. They are thin, flexible protein filaments that play a crucial role in maintaining cell shape, enabling cell movement, and facilitating intracellular transport. Actin filaments are polymers formed from the globular protein actin, which can exist in two main forms: G-actin (globular) and F-actin (filamentous). The polymerization process involves the assembly of G-actin monomers into a helical filament.

These dynamic structures are constantly being assembled and disassembled, a process regulated by a variety of actin-binding proteins. This dynamic nature allows cells to rapidly alter their shape and move. For instance, actin filaments are involved in muscle contraction through their interaction with myosin motor proteins. They also form structures like microvilli, which increase surface area, and are critical for cytokinesis, the division of the cytoplasm during cell division. Furthermore, actin filaments act as tracks along which motor proteins like myosin can transport vesicles and organelles within the cell. Their presence and activity are fundamental to a wide range of cellular processes.