Predicted to enable endopeptidase activator activity; enzyme binding activity; and identical protein binding activity. Predicted to be involved in several processes, including negative regulation of cytokine production; positive regulation of macromolecule metabolic process; and regulation of T cell activation. Predicted to act upstream of or within several processes, including negative regulation of CD4-positive, alpha-beta T cell proliferation; negative regulation of T cell cytokine production; and positive regulation of BMP signaling pathway. Predicted to be located in external side of plasma membrane. Orthologous to human VSIR (V-set immunoregulatory receptor). [provided by Alliance of Genome Resources, Apr 2022]