NFKB p105, TPL2 (COT) and ABIN2 form a stable complex Authored: Ray, KP, 2010-05-17 Edited: Jupe, S, 2010-05-17 Pubmed12667451 Pubmed12832462 Pubmed15169888 Pubmed15699325 Pubmed9950430 Reactome Database ID Release 43451634 Reactome, http://www.reactome.org ReactomeREACT_22206 Reviewed: Pinteaux, E, 2010-05-17 The C-terminal half of NFKB1 p105 forms a high-affinity stoichiometric association with Tpl2 via two distinct interactions (Belich et al. 1999; Beinke et al. 2003). The Tpl2 C-terminus (residues 398-467) binds to a region N-terminal to the p105 ankyrin repeat region (human p105 residues 497-534), whereas the Tpl2 kinase domain interacts with the p105 death domain (Beinke et al. 2003). In unstimulated macrophages, all detectable Tpl2 is associated with p105 (Belich et al. 1999; Lang et al. 2004). Binding to p105 maintains the stability of Tpl2 but inhibits Tpl2 MEK kinase activity by preventing access to MEK (Beinke et al. 2003; Waterfield et al. 2003). Tpl2 phosphorylation at Thr-290 may also play a role in the activation of Tpl2 (Cho & Tsichlis 2005). <br><br>A20-binding inhibitor of NFkappaB2 (ABIN-2) interacts with Tpl2 and p105 but preferentially forms a ternary complex with both proteins. As ABIN2 is a polyubiquitin binding protein, it has been suggested that it may facilitate recruitment of the p105/Tpl2 complex to the activated IKK complex, allowing IKK2 induced p105 phosphorylation and consequent Tpl2 activation.<br> NFKB p105:TPL2:ABIN2