Final answer:
Arp2/3-dependent actin polymerization drives the protrusion of lamellipodia at the leading edge of crawling cells, which is fundamental for cell mobility and directional movement.
Step-by-step explanation:
The Arp2/3 complex-dependent actin polymerization directly drives the lamellipodia protrusion at the leading edge of crawling cells. When the cell moves, the polymerization of actin creates a pushing force against the cell membrane, causing it to protrude outward in the form of lamellipodia. This is a fundamental process for cell mobility and is essential for the cell's interaction with its environment, determining its direction of movement.
Within the lamellipodia, the actin network undergoes continuous cycles of assembly and disassembly, with new branches forming and contributing to the protrusion of the cell membrane. This network is critical for the formation of new adhesions to the substrate as the cell moves, and while the actin-myosin interactions at the rear of the cell lead to retraction, it is the Actin polymerization at the front that causes the forward movement.