Activation of cAMP-dependent protein kinase is necessary for actin rearrangements in human neutrophils during phagocytosis.
We have investigated the role of cAMP and cAMP-dependent protein kinase (cAPK) in neutrophil phagocytosis. Inhibition of cAPK with H-89 reduced complement- and IgG-dependent phagocytosis to 83 and 46%, respectively. Fluorescence intensity measurements of phalloidin-stained actin in neutrophils showed a reduced amount of filamentous actin (F-actin) in pseudopods and around the phagosome in cells treated with H-89 or cAMP-elevating agents (forskolin and rolipram). The amount of phosphotyrosine-containing proteins was also reduced in pseudopods and around the phagosome. Taken together, the data show that cAMP/cAPK regulates F-actin reorganization during receptor-mediated phagocytosis, particularly triggered by IgG-FcR interaction. Our results support the hypothesis that active subcortical reorganization of F-actin is a prerequisite for FcR-mediated phagocytosis, but is less important during CR3-mediated ingestion.
Ydrenius
L
L
Department of Cell Biology, University of Linköping, Sweden. lisyd@mcb.liu.se
Majeed
M
M
Rasmusson
B J
BJ
Stendahl
O
O
Särndahl
E
E
D017868:Cyclic AMP-Dependent Protein Kinases / Q000276:immunology*; D004789:Enzyme Activation / Q000276:immunology; D006801:Humans; D018375:Neutrophil Activation / Q000276:immunology; D009504:Neutrophils / Q000276:immunology* / Q000648:ultrastructure; D010587:Phagocytosis / Q000276:immunology*; D015398:Signal Transduction / Q000276:immunology
D017868:Cyclic AMP-Dependent Protein Kinases