Integrin-associated protein is a ligand for the P84 neural adhesion molecule

P84 (also known as SHPS-1, BIT, and SIRP) is a heterophilic adhesive membra ne protein involved in receptor tyrosine kinase signaling that is found at synapses in the mammalian central nervous system and in non-neural tissues. We have identified a binding partner for P84 using an expression cloning s trategy. Here we report that integrin-associated protein (IAP/CD47) is a pr edominant binding partner of P84. Immunohistochemistry reveals a virtually identical distribution of P84 and IAP in a variety of adult brain regions. Because IAP has been implicated in cell signaling in cells of the immune sy stem, P84 and LAP represent a heterophilic binding pair that is likely to b e involved in bi-directional signaling at the synapse and in other tissues.