Insights from human NF-κB knockouts.

The well-studied NF-κB signaling system is a key mediator of the inflammatory response. Large-scale sequencing studies in humans now allow initial insights into non-essential human genes in which both alleles carry mutations that prevent protein expression or function. Here, we compiled the non-essential genes identified in various sequencing studies and analyzed the occurrence of knockouts in the human NF-κB signaling system. This revealed a lower knockout frequency in the NF-κB system compared to the entire genome. Since drugs inhibiting NF-κB pathway components were unsuccessful in clinical trials so far, the naturally occurring knockouts of NF-κB and its upstream regulators could provide new candidates for therapeutic intervention. To investigate the potential functional importance of posttranslational modifications (PTMs) occurring on NF-κB components, we analyzed not only their evolutionary conservation but also, as a second criterion, their genetic constraint in the sequenced individuals. This approach revealed the absence of missense mutations at key modification sites involved in NF-κB activation and identified additional candidate sites for future studies.