Tumor necrosis factor receptor-associated factor 6 (TRAF6) regulates adaptive
immunity, innate immunity and bone metabolism. TRAF6 is a ubiquitin
(Ub) ligase that mediates the activation of protein kinases, such as transforming
growth factor beta-activated kinase (TAK1) and IκB kinase (IKK), by
catalyzing the formation of a unique polyubiquitin chain linked through Lys 63
of Ub. TRAF6 is essential for activating NFκB signaling pathway in response
to interleukin-1 and Toll-like receptor ligands. The coiled-coil domain of
TRAF6 is essential for its auto-ubiquitination and activating NFκB signaling
pathway. TRAF6 interacts with various protein kinases including IRAK1/IRAK,
SRC and PKCζ, which provides a link between distinct signaling pathways.