All three isoforms of GRO are CXC chemokines that can signal through the CXCR1 or CXCR2 receptors. The GRO proteins chemoattract and activate neutrophils and basophils. Recombinant Human GRO-β is a 7.9 kDa protein consisting of 73 amino acids, including the ‘ELR’ motif common to the CXC chemokine family that binds to CXCR1 or CXCR2.