Involved in vitamin D transport and storage, scavenging of extracellular G-actin, enhancement of the chemotactic activity of C5 alpha for neutrophils in inflammation and macrophage activation. Associates with membrane-bound immunoglobulin on the surface of B-lymphocytes and with IgG Fc receptor on the membranes of T-lymphocytes. Interacts with LRP2; the interaction is required for renal uptake of GC in complex with 25-hydroxyvitamin D3. Belongs to the ALB/AFP/VDB family.