IRAK4 phosphorylates IRAK1 Authored: Ray, KP, 2010-05-17 EC Number: 2.7.11 Edited: Jupe, S, 2010-05-17 MyD88 recruits unphosphorylated IRAK1 to the signaling complex. IRAK1 is then rapidly activated and autophosphorylates in a region that is outside the kinase domain (Cao et al. 1996). Several pieces of evidence suggest that IRAK4 triggers IRAK1 activation by phosphorylating its kinase activation loop, leading to IRAK1 autophosphorylation (Suzuki et al. 2002): in vitro kinase assays indicate that IRAK1 can be a direct substrate of IRAK4 (Li et al. 2002); IRAK1 phosphorylation by IRAK4 is independent of and precedes IRAK1 activation and autophosphorylation; IRAK1 autophosphorylation is partially inhibited in cells overexpressing a kinase-inactive IRAK4 protein (Li et al. 2002). Pubmed11923871 Pubmed11960013 Pubmed12297423 Pubmed8599092 Reactome Database ID Release 43446694 Reactome, http://www.reactome.org ReactomeREACT_22125 Reviewed: Pinteaux, E, 2010-05-17 has a Stoichiometric coefficient of 2 IL1 receptor complex- activated IRAK4:TOLLIP:p-IRAK1 IL1 receptor complex-activated IRAK4:TOLLIP:IRAK1