|Neuronal RING finger protein 11 (RNF11) regulates canonical NF-κB signaling.
|Year of Publication
|Pranski EL, Dalal NV, Herskowitz JH, Orr AL, Roesch LA, Fritz JJ, Heilman C, Lah JJ, Levey AI, Betarbet RS
|2012 Apr 16
|Animals, Carrier Proteins, Cell Line, Tumor, Cells, Cultured, Gene Knockdown Techniques, Humans, Mice, Mice, Inbred C57BL, Neurons, NF-kappa B, Signal Transduction
BACKGROUND: The RING domain-containing protein RING finger protein 11 (RNF11) is a member of the A20 ubiquitin-editing protein complex and modulates peripheral NF-κB signaling. RNF11 is robustly expressed in neurons and colocalizes with a population of α-synuclein-positive Lewy bodies and neurites in Parkinson disease patients. The NF-κB pathway has an important role in the vertebrate nervous system, where the absence of NF-κB activity during development can result in learning and memory deficits, whereas chronic NF-κB activation is associated with persistent neuroinflammation. We examined the functional role of RNF11 with respect to canonical NF-κB signaling in neurons to gain understanding of the tight association of inflammatory pathways, including NF-κB, with the pathogenesis of neurodegenerative diseases.
METHODS AND RESULTS: Luciferase assays were employed to assess NF-κB activity under targeted short hairpin RNA (shRNA) knockdown of RNF11 in human neuroblastoma cells and murine primary neurons, which suggested that RNF11 acts as a negative regulator of canonical neuronal NF-κB signaling. These results were further supported by analyses of p65 translocation to the nucleus following depletion of RNF11. Coimmunoprecipitation experiments indicated that RNF11 associates with members of the A20 ubiquitin-editing protein complex in neurons. Site-directed mutagenesis of the myristoylation domain, which is necessary for endosomal targeting of RNF11, altered the impact of RNF11 on NF-κB signaling and abrogated RNF11's association with the A20 ubiquitin-editing protein complex. A partial effect on canonical NF-κB signaling and an association with the A20 ubiquitin-editing protein complex was observed with mutagenesis of the PPxY motif, a proline-rich region involved in Nedd4-like protein interactions. Last, shRNA-mediated reduction of RNF11 in neurons and neuronal cell lines elevated levels of monocyte chemoattractant protein 1 and TNF-α mRNA and proteins, suggesting that NF-κB signaling and associated inflammatory responses are aberrantly regulated in the absence of RNF11.
CONCLUSIONS: Our findings support the hypothesis that, in the nervous system, RNF11 negatively regulates canonical NF-κB signaling. Reduced or functionally compromised RNF11 could influence NF-κB-associated neuronal functions, including exaggerated inflammatory responses that may have implications for neurodegenerative disease pathogenesis and progression.
|PubMed Central ID
|P30NS055077 / NS / NINDS NIH HHS / United States
ES012870 / ES / NIEHS NIH HHS / United States
ES015777 / ES / NIEHS NIH HHS / United States
AG025688 / AG / NIA NIH HHS / United States
NS007480 / NS / NINDS NIH HHS / United States