A model to explain how autoantibodies to BRAF may activate BRAF. (A) In RA, cell death may release BRAF outside the cell and BRAF could be recognized by autoantibodies. (B) Autoantibodies to BRAF might enter the cell as immune complexes. (C) Immune complexes could be dissociated. Autoantibodies to BRAF might access to intracellular BRAF, stabilize BRAF in active conformation by binding its catalytic domain and provoke MAP kinase activation.