The protein encoded by this gene is a member of the TNF-receptor superfamily. This receptors can interact with various TRAF family proteins, through which this receptor induces the activation of NF-kappa B and MAPK8/JNK. This receptor and its ligand are important regulators of the interaction between T cells and dendritic cells. This receptor is also an essential mediator for osteoclast and lymph node development. Mutations at this locus have been associated with familial expansile osteolys