T6BP, a TRAF6-interacting protein involved in IL-1 signaling.

We report the identification of a TRAF-interacting protein, T6BP, that specifically associates with TRAF6. This interaction occurs between the coiled-coil region of T6BP and the N-terminal ring finger and zinc finger domains of TRAF6. IL-1, but not tumor necrosis factor, induces TRAF6-T6BP complex formation in a ligand-dependent manner. Formation of the TRAF6-T6BP complex depends on the presence of the IL-1 receptor-associated kinase (IRAK). After IL-1 stimulation, TRAF6 can exist in two separate complexes, TRAF6-IRAK or TRAF6-T6BP, but IRAK is not present in TRAF6-T6BP complexes. T6BP does not seem to play a direct role in activation of IkappaB kinases or Jun N-terminal kinase.