Involvement of Heterotrimeric G Proteins in Phagocytosis and Recycling from the Phagosomal Compartment

DAMIANI MT; COLOMBO MI

EXPERIMENTAL CELL RESEARCH

Academic Press

Lugar: USA; Año: 2001 vol. 271 p. 189 - 199

0014-4827

Phagocytosis is a receptor-mediated process by which specialized cell types engulf large extracellular particles. Phagosome maturation involves a series of intracellular membrane fusion and budding events resulting in the delivery of particles to compartments enriched in lysosomal hydrolases where they are digested. Substantial amounts of plasma membrane and many phagosomal proteins, such as receptors, rapidly recycle to the plasma membrane following phagosome formation. Despite the importance of this recycling pathway in phagosome maturation and in the retrieval of immunogenic peptides from phagosomes, the molecular machinery involved is largely unknown. To assess the participation of GTPases in phagocytosis and recycling from phagosomes we used aluminum fluoride (AIF4 2), which activates the GDP-bound form of stimulatory and inhibitory trimeric G proteins. AlF4 2 inhibited both the uptake to and the recycling from the phagosomal compartment. Cholera toxin, which activates Gas, and pertussis toxin, which  ncouples Gi and Go from receptors, were effective inhibitors of phagocytosis. However, both toxins stimulated recycling from phagosomes. These results suggest that more than one GTP-binding protein participates either directly or indirectly not only in phagocytosis, but also in maturation and recycling from phagosomes, and thereby assign a role for heterotrimeric G proteins in controlling traffic through the phagocytic pathway. 4 2), which activates the GDP-bound form of stimulatory and inhibitory trimeric G proteins. AlF4 2 inhibited both the uptake to and the recycling from the phagosomal compartment. Cholera toxin, which activates Gas, and pertussis toxin, which  ncouples Gi and Go from receptors, were effective inhibitors of phagocytosis. However, both toxins stimulated recycling from phagosomes. These results suggest that more than one GTP-binding protein participates either directly or indirectly not only in phagocytosis, but also in maturation and recycling from phagosomes, and thereby assign a role for heterotrimeric G proteins in controlling traffic through the phagocytic pathway.