Disclosed are novel isolated tumor necrosis factor receptor associated factor (TRAF) 6 inhibiting proteins or functional derivatives thereof. The proteins contain a KRAB domain at their N-termini amd 14 C2H2 type zinc finger motifs at their C-termini, bind to TFAF6 but do not bind to TRAF2 and TRAF3, and inhibit activities of NF- kappa B or AP-1 in a signal transduction pathway of tumor necrosis factor (TNF) by ineracting with TRAF6.
