Here's why:
* Structure: Microvilli are finger-like projections on the surface of cells, particularly those involved in absorption. They have a core of actin filaments bundled together, which provides the structural support and rigidity.
* Function: This actin core acts like a "scaffolding" within the microvillus, maintaining its shape and preventing collapse.
* Cross-linking: Proteins like villin and fimbrin help to further organize and cross-link the actin filaments, adding to their stability.
In summary, actin, along with its associated proteins, forms the structural basis for microvilli, giving them their characteristic stiff, finger-like appearance and enabling their function in absorption.
