Released during platelet aggregation. Neutralizes the anticoagulant effect of heparin because it binds more strongly to heparin than to the chondroitin-4-sulfate chains of the carrier molecule. Chemotactic for neutrophils and monocytes. Inhibits endothelial cell proliferation, the short form is a more potent inhibitor than the longer form. Homotetramer (PubMed:7547867, PubMed:8031770). Interacts with TNFAIP6 (via Link domain) (PubMed:27044744). Short form. Belongs to the intercrine alpha (chemokine CxC) family. CXCL4 entry