SIRPA A gene on chromosome 20p13 that encodes a ubiquitous immunoglobulin-like cell surface receptor for CD47 that acts as a docking protein and induces translocation of PTPN6, PTPN11 and other binding partners from the cytosol to the plasma membrane. SIRPA supports adhesion of cerebellar neurons, neurite outgrowth and glial cell attachment, and may play a key role in intracellular signalling during synaptogenesis and in synaptic function. It downregulates receptor tyrosine kinase-coupled cellular responses induced by cell adhesion, growth factors and insulin; it also downregulates phagocytosis, mast cell activation and dendritic cell activation. CD47 binding prevents maturation of immature dendritic cells and inhibits cytokine production by mature dendritic cells. It is highly expressed in the brain.