E3 ubiquitin ligase catalyzing the covalent attachment of ubiquitin moieties onto substrate proteins. Involved in the TLR and IL-1 signaling pathways via interaction with the complex containing IRAK kinases and TRAF6. Mediates 'Lys-63'-linked polyubiquitination of IRAK1. Can activate the MAP (mitogen activated protein) kinase pathway leading to activation of ELK1. Not required for NF-kappa-B activation (By similarity).