TRAF6 and viral infectious disease: During viral infection, MyD88 recruits members of the interleukin-1 receptor-associated kinase (IRAK)-1 and/or -4 to activate transcription factors belonging to the NF-κB and activator protein 1 (AP-1) family via TRAF6 and transforming growth factor beta-activated kinase 1 (TAK1) [26,27,28].