Sequestosome 1/p62 is a scaffolding protein with several interaction modules that include a PB1 dimerization domain, a TRAF6 (tumor necrosis factor receptor-associated factor 6) binding site, and a ubiquitin-associating (UBA) domain. Here, we report that p62 functions to facilitate K63-polyubiquitination of TRAF6 and thereby mediates nerve growth factor-induced activation of the NF-kappaB pathway. In brain of p62 knock-out mice we did not recover polyubiquitinated TRAF6. The UBA domain binds polyubiquitin chains and deletion of p62-UBA domain or mutation of F406V within the ubiquitin binding pocket of the UBA domain abolished TRAF6 polyubiquitination. Likewise, deletion of p62 N-terminal dimerization domain or the TRAF6 binding site had similar effects on both polyubiquitination and oligomerization of TRAF6. Nerve growth factor treatment of PC12 cells induced TRAF6 polyubiquitination along with formation of a p62-TRAF6-IKKbeta-PKC iota signal complex, while inhibition of the p62/TRAF6 interaction had an opposite effect. These results provide evidence for a mechanism whereby p62 serves to regulate the NF-kappaB pathway.
SciCrunch is a data sharing and display platform. Anyone can create a custom portal where they can select searchable subsets of hundreds of data sources, brand their web pages and create their community. SciCrunch will push data updates automatically to all portals on a weekly basis. User communities can also add their own data to scicrunch, however this is not currently a free service.