The Transition from Circulating to Migrating Cells

The rolling behavior of neutrophils along the vascular endothelium is mediated by reversible binding of a constitutively expressed surface 

FPR N-formyl-met-leu-phe N-formyl-met-leu-phe binds with high affinity (K 1 nM) to FPR [440]. Many N-formyl peptide sequences bind this receptor with Kjs in the nanomolar and sub-nanomolar concentration ranges [107, 408]. 

FPRLl N-formyl-met-leu-phe N-formyl-met-leu-phe binds with low affinity (Kj -400 nM) to FPRLl [440]. The synthetic peptide Trp-Lys-Tyr-Met-Val-Met-NH2 is a chemoattractant that binds FPRLl with high affinity, but not FPR [60]. FPRLl has also been identified as the lipoxin A4 receptor, although lipoxin A4 is NOT a chemoattractant [103]. 

C5aR C5a C5a is a fragment from complement component C5 released during complement activation [42, 96]. 

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