Cell membrane protrusions are structures that extend from the surface of a cell. These protrusions include various types of cellular extensions such as microvilli, filopodia, lamellipodia, and invadopodia. They play crucial roles in cell adhesion, cell motility, and cell communication.
Microvilli are small finger-like projections on the cell surface that increase its surface area, allowing for enhanced absorption and secretion of substances. Filopodia are long, thin protrusions involved in cell adhesion and guiding cell movement during processes like cell migration and development. Lamellipodia are broad, sheet-like extensions that aid in cell migration by allowing the cell to move forward. Invadopodia are specialized protrusions involved in cell invasion, allowing cells to penetrate through tissues or extracellular matrix barriers.
Cell membrane protrusions are composed of actin filaments, which provide structural support and flexibility for these extensions. They are dynamic structures that can be extended or retracted in response to various stimuli, such as chemical signaling or mechanical forces.
The formation and regulation of cell membrane protrusions are tightly controlled by cellular signaling pathways and specific proteins. For example, small GTPases like Rho, Rac, and Cdc42 are crucial regulators of actin dynamics and play important roles in the formation and maintenance of different types of cell membrane protrusions.
Overall, cell membrane protrusions are essential for various cellular functions and processes, including cell adhesion, migration, communication, and invasion.
