Predicted to enable identical protein binding activity. Involved in B cell differentiation and B cell proliferation. Acts upstream of or within B cell receptor signaling pathway. Located in external side of plasma membrane; membrane raft; and multivesicular body. Part of B cell receptor complex. Is expressed in liver. Human ortholog(s) of this gene implicated in agammaglobulinemia. Orthologous to human CD79A (CD79a molecule). [provided by Alliance of Genome Resources, Apr 2022]