Potential interaction of WT and Mutant TNF-Receptor 1 and Pyruvate Kinase M2 in TNF-Receptor-Associated Periodic Fever Syndrome (TRAPS)

Abstract

Abstract Tumor Necrosis Factor (TNF) is a trimeric cytokine induces innate inflammatory responses or cell death through TNFR1. Extracellular mutations in TNFR1 are associated with Receptor-Associated Periodic Syndrome (TRAPS), an autosomal dominant autoinflammatory disorder characterized by recurring fevers, dermal and synovial inflammation and elevated risk of amyloidosis. Previous work by our group has demonstrated that a TRAPS-like mutation in TNFR1 leads to accumulation of the receptor in the ER, leading to abnormal MAPK activation and correlated with reduced glucose metabolism. To better understand how the mutant TNFR1 signals to induce these abnormal cellular phenotypes, we immunoprecipitated the wild-type and TRAPS-associated mutant receptors and performed mass spectroscopy to identify associated proteins. Both WT and Mutant were able to bind the known adapter protein TRADD, but not the death domain (DD) deleted mutant. In addition, we also identified a novel association of WT and mutant TNFR1 with pyruvate kinase M2 (PKM2). Pyruvate kinase is the rate limiting enzyme in glycolysis and PKM2, and has been shown to be more activated in cancer cells, leading to abnormal metabolism known as the Warburg effect where cells undergo aerobic glycolysis. In addition, other studies suggest a link between activated PKM2 and induction of inflammatory responses, increasing TNF and IL1-b production. To confirm this interaction, we utilized colocalization microscopy techniques and IP/Western blot analysis which inferred a link between PKM2 and mutant TNFR1 more than the wild-type. Association between PKM2 TNFR1 may be a novel link between TNFR1 signaling and metabolism and explain some of the metabolic abnormalities in TRAPS cells.