LA-PF4 stimulates DNA synthesis, mitosis, glycolysis, intracellular cAMP accumulation, prostaglandin E2 secretion, and synthesis of hyaluronic acid and sulfated glycosaminoglycan. It also stimulates the formation and secretion of plasminogen activator by human synovial cells. NAP-2 is a ligand for CXCR1 and CXCR2, and NAP-2, NAP-2(73), NAP-2(74), NAP-2(1-66), and most potent NAP-2(1-63) are chemoattractants and activators for neutrophils. TC-1 and TC-2 are antibacterial proteins, in vitro released from activated platelet alpha-granules. CTAP-III(1-81) is more potent than CTAP-III desensitize chemokine-induced neutrophil activation.

Belongs to the intercrine alpha (chemokine CxC) family.

Proteolytic removal of residues 1-9 produces the active peptide connective tissue-activating peptide III (CTAP-III) (low-affinity platelet factor IV (LA-PF4)).
Proteolytic removal of residues 1-13 produces the active peptide beta-thromboglobulin, which is released from platelets along with platelet factor 4 and platelet-derived growth factor.
NAP-2(1-66) is produced by proteolytical processing, probably after secretion by leukocytes other than neutrophils.
NAP-2(73) and NAP-2(74) seem not be produced by proteolytical processing of secreted precursors but are released in an active form from platelets.

Secreted.