NAP-2 (CXCL7)

Neutrophil Activating Peptide 2 (NAP2), Connective Tissue Activating Protein III (CTAPIII) and βthrombogulin (βTG), are proteolytically processed carboxylterminal fragments of platelet basic protein (PBP) which is found in the alphagranules of human platelets. NAP2 is a member of the CXC chemokines. Similar to other ELR domain containing CXC chemokines such as IL8 and the GRO proteins, NAP2 has been shown to bind CXCR2 and to chemoattract and activate neutrophils. Although CTAPIII, βTG and PBP represent aminoterminal extended variants of NAP 2 and possess the same CXC chemokine domains, these proteins do not exhibit NAP2 activity. It has been shown that the additional aminoterminal residues of CTAP III masks the critical ELR receptor binding domain that is exposed on NAP2 and may account for lack of NAP2 activity.