Calcium-sensing soluble adenylyl cyclase mediates TNF signal transduction in human neutrophils Academic Article uri icon


MeSH Major

  • Adenylyl Cyclases
  • Calcium Signaling
  • Neutrophil Activation
  • Neutrophils
  • Receptors, Calcium-Sensing
  • Tumor Necrosis Factor-alpha


  • Through chemical screening, we identified a pyrazolone that reversibly blocked the activation of phagocyte oxidase (phox) in human neutrophils in response to tumor necrosis factor (TNF) or formylated peptide. The pyrazolone spared activation of phox by phorbol ester or bacteria, bacterial killing, TNF-induced granule exocytosis and phox assembly, and endothelial transmigration. We traced the pyrazolone's mechanism of action to inhibition of TNF-induced intracellular Ca2+ elevations, and identified a nontransmembrane ("soluble") adenylyl cyclase (sAC) in neutrophils as a Ca2+-sensing source of cAMP. A sAC inhibitor mimicked the pyrazolone's effect on phox. Both compounds blocked TNF-induced activation of Rap1A, a phox-associated guanosine triphosphatase that is regulated by cAMP. Thus, TNF turns on phox through a Ca2+-triggered, sAC-dependent process that may involve activation of Rap1A. This pathway may offer opportunities to suppress oxidative damage during inflammation without blocking antimicrobial function.

publication date

  • August 2005



  • Academic Article



  • eng

PubMed Central ID

  • PMC2213086

Digital Object Identifier (DOI)

  • 10.1084/jem.20050778

PubMed ID

  • 16043520

Additional Document Info

start page

  • 353

end page

  • 61


  • 202


  • 3