Rakusõrmikud

Rakusõrmikud, also known as cellular fingers, are temporary, dynamic extensions of the cell membrane that cells use to explore their environment, interact with other cells, and move. These finger-like projections are primarily composed of actin filaments, which are a type of protein filament found within the cell's cytoplasm. The polymerization and depolymerization of these actin filaments, regulated by various proteins, drive the formation, extension, and retraction of rakusõrmikud.

These structures play crucial roles in several biological processes. During cell migration, rakusõrmikud are extended in the direction of movement, allowing the cell to adhere to the substrate and pull itself forward. In the immune system, rakusõrmikud are involved in phagocytosis, where immune cells engulf pathogens or cellular debris, and in cell-cell recognition and adhesion, important for immune surveillance and response. They are also vital for development, contributing to processes like tissue formation and neuronal guidance. The dynamic nature of rakusõrmikud allows cells to respond rapidly to external stimuli and adapt their shape and behavior accordingly. Their formation and function are tightly controlled by complex signaling pathways within the cell.