Fc-receptor-mediated phagocytosis is regulated by mechanical properties of the target

• Published in: Journal of cell science Vol. 115; no. Pt 4; pp. 849 - 856
• Main Authors: Beningo, Karen A., Wang, Yu-li
• Format: Journal Article
• Language: English
• Published: Legacy CDMS 15.02.2002
• Subjects: Acrylic Resins - chemistry; Acrylic Resins - metabolism; Actin Cytoskeleton - drug effects; Actin Cytoskeleton - ultrastructure; Animals; Cells, Cultured; Life Sciences (General); Lysophospholipids - metabolism; Macrophages - drug effects; Macrophages - physiology; Macrophages - ultrastructure; Mice; Mice, Inbred C3H; Opsonin Proteins - metabolism; Particle Size; Phagocytosis; rac1 GTP-Binding Protein - metabolism; Receptors, Fc - metabolism; Stress, Mechanical; Non-Nasa Center; Nasa Discipline Cell Biology; Nasa Program Fundamental Space Biology; NASA Program Fundamental Space Biology; NASA Discipline Cell Biology; Non-NASA Center
• ISSN: 0021-9533; 1477-9137
• DOI: 10.1242/jcs.115.4.849

Phagocytosis is an actin-based process used by macrophages to clear particles greater than 0.5 microm in diameter. In addition to its role in immunological responses, phagocytosis is also necessary for tissue remodeling and repair. To prevent catastrophic autoimmune reactions, phagocytosis must be tightly regulated. It is commonly assumed that the recognition/selection of phagocytic targets is based solely upon receptor-ligand binding. Here we report an important new criterion, that mechanical parameters of the target can dramatically affect the efficiency of phagocytosis. When presented with particles of identical chemical properties but different rigidity, macrophages showed a strong preference to engulf rigid objects. Furthermore, phagocytosis of soft particles can be stimulated with the microinjection of constitutively active Rac1 but not RhoA, and with lysophosphatidic acid, an agent known to activate the small GTP-binding proteins of the Rho family. These data suggest a Rac1-dependent mechanosensory mechanism for phagocytosis, which probably plays an important role in a number of physiological and pathological processes from embryonic development to autoimmune diseases.