Receptor for a number of inflammatory CC-chemokines including CCL3/MIP-1-alpha, CCL4/MIP-1-beta and RANTES and subsequently transduces a signal by increasing the intracellular calcium ion level. May play a role in the control of granulocytic lineage proliferation or differentiation (PubMed:16806494). Participates in T-lymphocyte migration to the infection site by acting as a chemotactic receptor (By similarity) (PubMed:16806494). 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 GRK2. Interacts with ARRB1 and ARRB2. Interacts with CNIH4. Interacts with S100A4; this interaction stimulates T-lymphocyte chemotaxis. Sulfated on at least 2 of the N-terminal tyrosines. Sulfation is required for efficient binding of the chemokines, CCL3 and CCL4 (By similarity). O-glycosylated, but not N-glycosylated. Ser-6 appears to be the major site. Also sialylated glycans present which contribute to chemokine binding. Thr-16 and Ser-17 may also be glycosylated and, if so, with small moieties such as a T-antigen. Palmitoylation in the C-terminal is important for cell surface expression. Phosphorylation on serine residues in the C-terminal is stimulated by binding CC chemokines especially by APO-RANTES. Belongs to the G-protein coupled receptor 1 family.