Interacts with PRAF2. Efficient ligand binding to CCL3/MIP-1alpha and CCL4/MIP-1beta requires sulfation, O-glycosylation and sialic acid modifications. Glycosylation on Ser-6 is required for efficient binding of CCL4. Interacts with ADRBK1. Interacts with ARRB1 and ARRB2 (By similarity).