This gene encodes a member of the TNF receptor associated factor (TRAF) family of adaptor proteins that mediate signaling events from members of the TNF receptor and Toll/IL-1 receptor families to activate transcription factors such as NF-kappa-B and AP-1. The product of this gene is essential for perinatal and postnatal survival. Mice deficient in this protein exhibit osteopetrosis and defective in development of epidermal appendixes, normal B cell differentiation, lymph node organogenesis, interleukin-1 signaling, lipopolysaccharide signaling and neural tube closure. This protein possesses ubiquitin ligase activity. Alternate splicing of this gene results in multiple transcript variants. [provided by RefSeq, Dec 2014]