Receptor for SIRPA, binding to which prevents maturation of immature dendritic cells and inhibits cytokine production by mature dendritic cells. Interaction with SIRPG mediates cell-cell adhesion, enhances superantigen-dependent T-cell-mediated proliferation and costimulates T-cell activation. Plays an important role in memory formation and synaptic plasticity in the hippocampus. May play a role in membrane transport and/or integrin dependent signal transduction. May prevent premature elimination of red blood cells. May be involved in membrane permeability changes induced following virus infection. May play a role in memory formation (By similarity). Has a role in both cell adhesion by acting as an adhesion receptor for THBS1 on platelets, and in the modulation of integrins. Monomer. Interacts with SIRPA, SIRPG, UBQLN1 and UBQLN2 (By similarity). Interacts with THBS1 and fibrinogen. Widely expressed, detected in kidney, liver, platelets, thymus, spleen, macrophages, bone marrow and peripheral blood mononuclear cells.