Same Receptor, Different Effects

Science's STKE  23 May 2000:
Vol. 2000, Issue 33, pp. tw7
DOI: 10.1126/stke.2000.33.tw7

The anti-inflammatory action of annexin I, a secreted calcium- and phospholipid-binding protein, includes inhibiting neutrophil transmigration from the blood into tissue. Walther et al. report that annexin I acts through the formyl peptide receptor (FPR) on human neutrophils. In contrast, bacterial formyl peptides, the classical FPR ligands, are proinflammatory. When bound to the receptor, annexin I-derived peptides and formyl peptides elicit a similar elevation in intracellular calcium in a G-protein-dependent manner. Competition assays indicate that the two peptides likely bind to different regions of FPR. The authors propose that the two different ligands activate different receptor-initiated signaling cascades that result in opposing inflammatory responses.

Walther, A., Riehemann, K., and Gerke, V. (2000) A novel ligand of the formyl peptide receptor: Annexin I regulates neutrophil extravasation by interacting with the FPR. Mol. Cell 5: 831-840. [Online Journal]