Ankyrin-rich membrane spanning protein plays a critical role in nuclear factor-κb signaling

Activation of nuclear factor-κB (NF-κB), a key feature of the neurotrophin signaling, has been shown to be critical for neuronal survival under pathologic settings. However, the precise mechanism by which neurotrophins activate NF-κB is not well understood. Here we report that the Ankyrin-rich Membrane Spanning (ARMS/Kidins220) protein, a novel transmembrane substrate of tropomyosin receptor kinase B (TrkB), plays an important role in NF-κB signaling elicited by brain-derived neurotrophic factor (BDNF). Accordingly, depletion of ARMS by specific RNA interference, or disruption of ARMS-TrkB interaction with expression of dominant-negative ARMS mutant, abolished BDNF-induced signaling to NF-κB. Our data further suggests that ARMS may promote NF-κB signaling via activation of mitogen-activated kinase (MAPK) and IκB kinase (IKK), thereby facilitating phosphorylation of RelA (major NF-κB subunit) at an IKK-sensitive site. The results shown here identify ARMS as a major factor that links neurotrophin signaling to NF-κB.