Fagolizosoma

Fagolizosoma is the term used in some languages for the phagolysosome, a membrane-bound intracellular compartment formed by the fusion of a phagosome with a lysosome during phagocytosis. In English, the standard term is phagolysosome. This organelle integrates cargo digestion with antimicrobial and antigen-processing functions within phagocytic cells.

Formation and maturation: After a particle or microorganism is internalized, the nascent phagosome undergoes maturation. Early phagosomes acquire Rab5 and other early endosomal markers, then mature into late phagosomes with Rab7. Fusion with lysosomes yields the phagolysosome. The lumen becomes highly acidic through the action of vacuolar-type H+-ATPases, a condition that activates hydrolytic enzymes.

Contents and function: Phagolysosomes contain hydrolytic enzymes, including proteases, nucleases, lipases, and glycosidases, along with antimicrobial peptides and reactive oxygen and nitrogen species. The acidic environment optimizes enzyme activity and antimicrobial action, enabling digestion of engulfed material. Degraded products can be recycled by the cell or presented to the immune system as antigens.

Biological significance: They are central to innate immunity, intracellular digestion, and antigen processing for MHC class II presentation in antigen-presenting cells. Some pathogens have evolved strategies to interfere with phagolysosome formation or function, allowing intracellular survival or replication.

Regulation and markers: Fusion is driven by SNARE proteins, Rab GTPases, and tethering complexes such as HOPS. Phagolysosomes are commonly identified by lysosomal markers like LAMP1/2 and by acidity indicators; their pH profile is a key feature of their antimicrobial activity.