Involved in several processes, including negative regulation of cytokine production; negative regulation of lymphocyte proliferation; and oligodendrocyte apoptotic process. Located in axon. Is intrinsic component of plasma membrane. Is expressed in several structures, including alimentary system; lung; metanephros; nervous system; and nose. Orthologous to human TNFRSF21 (TNF receptor superfamily member 21). [provided by Alliance of Genome Resources, Apr 2022]