Enables identical protein binding activity and signaling receptor binding activity. Acts upstream of or within several processes, including positive regulation of osteoblast differentiation; regulation of T cell proliferation; and regulation of cytokine production. Located in external side of plasma membrane. Is expressed in several structures, including embryo endoderm; genitourinary system; hemolymphoid system; liver; and musculoskeletal system. Orthologous to human CD276 (CD276 molecule). [provided by Alliance of Genome Resources, Apr 2022]