What leukocyte function is critically dependent on the polymerization of actin?

What leukocyte function is critically dependent on the polymerization of actin?

• A. Intravasation
• B. Diapedesis
• C. Phagocytosis
• D. Apoptosis

Answer: (C)

Phagocytosis is a critical process carried out by leukocytes, particularly by types such as macrophages and neutrophils. This process involves the engulfing of pathogens, dead cells, and debris from the body. Actin polymerization plays a fundamental role in this mechanism by facilitating the movement and shape changes of the leukocyte's membrane. During phagocytosis, when a leukocyte comes into contact with a target particle (such as a bacterium), signaling pathways are activated that lead to the polymerization of actin filaments at the site of contact. This polymerization drives the extension of pseudopodia, which are membrane protrusions that surround and eventually engulf the target particle. Once engulfed, the particle is enclosed in a phagosome, which then fuses with lysosomes to form a phagolysosome where the pathogen is degraded. This function emphasizes the importance of the cytoskeleton, particularly actin filaments, in enabling leukocytes to effectively respond to infections and clear cellular debris. Understanding this process illustrates the critical role actin plays in the immune response and the overall physiology of leukocytes.

Phagocytosis is a critical process carried out by leukocytes, particularly by types such as macrophages and neutrophils. This process involves the engulfing of pathogens, dead cells, and debris from the body. Actin polymerization plays a fundamental role in this mechanism by facilitating the movement and shape changes of the leukocyte's membrane.

During phagocytosis, when a leukocyte comes into contact with a target particle (such as a bacterium), signaling pathways are activated that lead to the polymerization of actin filaments at the site of contact. This polymerization drives the extension of pseudopodia, which are membrane protrusions that surround and eventually engulf the target particle. Once engulfed, the particle is enclosed in a phagosome, which then fuses with lysosomes to form a phagolysosome where the pathogen is degraded.

This function emphasizes the importance of the cytoskeleton, particularly actin filaments, in enabling leukocytes to effectively respond to infections and clear cellular debris. Understanding this process illustrates the critical role actin plays in the immune response and the overall physiology of leukocytes.