A designer polyQ fusion protein modulates NF-κB signaling by sequestering P65/RelA into aggregates.

The transcription factor P65 is a subunit of the NF-κB complex that regulates expression of pro-inflammatory cytokines, thereby controlling the innate immune response. Excessive activation of NF-κB is commonly associated with various chronic inflammatory conditions. We previously established a polyglutamine (polyQ) fusion strategy to modulate biological processes by sequestering the targeted proteins. Here, we report a designer polyQ fusion (Atx793Q-N172-LDEL) that modulates the NF-κB signaling by sequestering P65 into aggregates. The fusion protein can interact with cellular P65 via its LDEL peptide sequence and specifically sequester it into aggregates or inclusions. This sequestration impedes the nuclear translocation process of P65, reduces its nuclear abundancy, and thereby attenuates the activity of NF-κB signaling and expression of the downstream genes, such as TNF-α and IL-6. This study provides therapeutic potential for treating inflammation and autoimmune disorders by targeting the P65 protein directly.