Mikrotrådar

Mikrotrådar, also known as microfilaments, are the thinnest type of protein filament within the cytoplasm of eukaryotic cells. They are dynamic structures that are constantly assembling and disassembling, playing a crucial role in cell shape, movement, and internal transport. The primary protein subunit of microfilaments is actin, a globular protein that polymerizes into long, double-helical filaments. These filaments are organized into various networks and bundles within the cell, often associated with other proteins that regulate their assembly, disassembly, and interaction with other cellular components.

Microfilaments are fundamental to several cellular processes. They provide mechanical support, helping to maintain cell shape and resist external forces. In muscle cells, actin filaments interact with myosin filaments to generate the force required for contraction. Cell motility, such as amoeboid movement and the formation of lamellipodia and filopodia in crawling cells, relies heavily on the directed assembly and disassembly of microfilaments. Furthermore, microfilaments are involved in intracellular transport, guiding the movement of vesicles and organelles along the cell's internal framework. They also play a role in cytokinesis, the process of cell division, by forming the contractile ring that pinches the parent cell into two daughter cells. The dynamic nature of microfilaments allows cells to rapidly adapt their structure and function in response to internal and external signals.