Phagocytosis and phagosome maturation are regulated by calcium in J774 macrophages interacting with unopsonized prey.
Phagocytosis by neutrophils, macrophages, and other professional phagocytes requires rapid remodeling of actin. Early phagosomes are surrounded by a rim of F-actin that is disassembled during phagosomoal maturation. Breakdown of periphagosomal F-actin and phagolysosome fusion are calcium dependent processes in neutrophils interacting with serum-opsonized prey, but appears to be calcium independent in macrophages interacting with serum- or IgG-opsonized prey. In the present study, we found that calcium was necessary for phagocytosis, breakdown of periphagosomal F-actin, and phagosomal maturation in J774 macrophages interacting with unopsonized prey. We also observed that lipophosphoglycan (LPG) from Leishmania donovani promastigotes required calcium to exert its inhibitory effect on macrophage phagocytosis and periphagosomal F-actin breakdown. We conclude that calcium is essential for phagocytosis, depolymerization of periphagosomal F-actin, and phagosomal maturation in J774 macrophages interacting with unopsonized prey, as well as for proper functioning of LPG.
Tejle
Katarina
K
Division of Medical Microbiology, Department of Molecular and Clinical Medicine, Faculty of Health Sciences, Linköping University, S-58185 Linköping, Sweden. katte@imk.liu.se
Magnusson
Karl-Eric
KE
Rasmusson
Birgitta
B
D000199:Actins / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling / Q000502:physiology*; D002454:Cell Differentiation / Q000502:physiology*; D002460:Cell Line; D005110:Extracellular Space / Q000378:metabolism; D006028:Glycosphingolipids / Q000494:pharmacology; D008264:Macrophages / Q000378:metabolism*; D051379:Mice; D010587:Phagocytosis / Q000502:physiology*; D010588:Phagosomes / Q000378:metabolism*; D012441:Saccharomyces cerevisiae
D000199:Actins; D006028:Glycosphingolipids; C008290:lipophosphonoglycan; D002118:Calcium