Compartmentalization of PDE-4 and cAMP-dependent Protein Kinase in Neutrophils and Macrophages During Phagocytosis

Cell Biochem Biophys. 1998;28(2-3):251-75. doi: 10.1007/BF02737813.


The compartmentalization of cAMP in human neutrophils during phagocytosis of serum-opsonized zymosan suggests that cAMP is an important second messenger for regulating phagocytosis. Type 4 cAMP-specific phosphodiesterase (PDE-4), cAMP-dependent protein kinase (PKA), and adenylate cyclase are the principal effector molecules for cAMP regulation in phagocytes. Immunofluorescence microscopy demonstrated that PDE-4 isoforms (HSPDE-4A, HSPDE-4B, HSPDE-4D) were targeted to the forming phagosome in neutrophils, and were colocalized with the catalytic subunit of PKA and degranulated myeloperoxidase. Phagocytosis and accumulation of PDE-4 and PKA near adherent zymosan were inhibited by elevating cAMP levels with forskolin or rolipram. cAMP, PDE-4, and PKA were localized at sites of zymosan adherence in cells treated with cytochalasin D to inhibit phagosome formation, suggesting that zymosan engagement to Fc/CR3 receptors triggers cAMP elevations at sites of phagocytosis. HSPDE-4A, HSPDE-4B, HSPDE-4D, and PKA also were localized at the forming phagosome in monocyte-derived macrophages, and the lysosomal marker CD63 demonstrated the absence of PDE-4 around internalized phagolysosomes. These results suggest that cAMP levels are focally regulated by PDE-4 at the nascent phagosome, and that PKA may phosphorylate proteins associated with pseudopodia formation and phagosome internalization.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • 3',5'-Cyclic-AMP Phosphodiesterases / analysis*
  • Cell Adhesion
  • Cell Compartmentation / immunology*
  • Colforsin / pharmacology
  • Cyclic AMP / analysis
  • Cyclic AMP-Dependent Protein Kinases / analysis*
  • Cyclic GMP / analysis
  • Cyclic Nucleotide Phosphodiesterases, Type 4
  • Cytochalasin D / pharmacology
  • Humans
  • Isoenzymes / analysis
  • Macrophages / enzymology*
  • Macrophages / immunology
  • Neutrophils / enzymology*
  • Neutrophils / immunology
  • Nucleic Acid Synthesis Inhibitors / pharmacology
  • Peroxidase / analysis
  • Phagocytosis
  • Phagosomes / enzymology
  • Phosphodiesterase Inhibitors / pharmacology
  • Pyrrolidinones / pharmacology
  • Rolipram
  • Signal Transduction / immunology
  • Zymosan


  • Isoenzymes
  • Nucleic Acid Synthesis Inhibitors
  • Phosphodiesterase Inhibitors
  • Pyrrolidinones
  • Colforsin
  • Cytochalasin D
  • Zymosan
  • Cyclic AMP
  • Peroxidase
  • Cyclic AMP-Dependent Protein Kinases
  • 3',5'-Cyclic-AMP Phosphodiesterases
  • Cyclic Nucleotide Phosphodiesterases, Type 4
  • Cyclic GMP
  • Rolipram