Predicted to enable signaling receptor binding activity. Involved in several processes, including CD40 signaling pathway; activation of phospholipase C activity; and positive regulation of macromolecule metabolic process. Acts upstream of or within several processes, including cellular response to lipopolysaccharide; defense response to virus; and positive regulation of T cell proliferation. Located in external side of plasma membrane and intracellular membrane-bounded organelle. Is expressed in central nervous system and retina. Used to study Guillain-Barre syndrome. Human ortholog(s) of this gene implicated in several diseases, including Henoch-Schoenlein purpura; autoimmune disease (multiple); chronic lymphocytic leukemia; chronic obstructive pulmonary disease; and systemic scleroderma. Orthologous to human CD86 (CD86 molecule). [provided by Alliance of Genome Resources, Apr 2022]