Description
Background: sTNF RI/TNFRSF1A is a receptor for TNFSF2/TNF-alpha and homotrimeric TNFSF1/lymphotoxin-alpha. The adapter molecule FADD recruits caspase-8 to the activated receptor. The resulting death-inducing signaling complex (DISC) performs caspase-8 proteolytic activation, which initiates the subsequent cascade of caspases (aspartate-specific cysteine proteases) mediating apoptosis. sTNF RI/TNFRSF1A contributes to the induction of non-cytocidal TNF effects including anti-viral state and activation of the acid sphingomyelinase. Binding of TNF to the extracellular domain leads to homotrimerization. The aggregated death domains provide a novel molecular interface that interacts specifically with the death domain of TRADD. Various TRADD-interacting proteins such as TRAFS, RIPK1 and possibly FADD, are recruited to the complex by their association with TRADD. This complex activates at least two distinct signaling cascades: apoptosis and NF-kappa-B signaling. The receptor interacts with BAG4, BRE, FEM1B, GRB2, SQSTM1 and TRPC4AP. sTNF RI/TNFRSF1A interacts with HCV core protein. The domain that induces A-SMASE is probably identical to the death domain. The N-SMASE activation domain (NSD) is both necessary and sufficient for activation of N-SMASE. Both the cytoplasmic membraneproximal region and the C-terminal region containing the death domain are involved in the interaction with TRPC4AP. The soluble form is produced from the membrane form by proteolytic processing. Defects in TNFRSF1A are the cause of familial hibernian fever (FHF), also known as tumor necrosis factor receptor-associated periodic syndrome (TRAPS). FHF is a hereditary periodic fever syndrome characterized by recurrent fever, abdominal pain, localized tender skin lesions and myalgia. Reactive amyloidosis is the main complication and occurs in 25% of cases.
Principle of the Assay: The OmniKine™ Human sTNF-R1 ELISA Kit contains the components necessary for quantitative determination of natural or recombinant Human sTNF-R1 concentrations within any experimental sample including cell lysates, serum and plasma. This particular immunoassay utilizes the quantitative technique of a "Sandwich" Enzyme-Linked Immunosorbent Assay (ELISA) where the target protein (antigen) is bound in a "sandwich" format by the primary capture antibodies coated to each well-bottom and the secondary detection antibodies added subsequently by the investigator. The capture antibodies coated to the bottom of each well are specific for a particular epitope on Human sTNF-R1 while the user-added detection antibodies bind to epitopes on the captured target protein. Amid each step of the procedure, a series of wash steps must be performed to ensure the elimination of non-specific binding between proteins to other proteins or to the solid phase. After incubation and "sandwiching" of the target antigen, a peroxidase enzyme is conjugated to the constant heavy chain of the secondary antibody (either covalently or via Avidin/Streptavidin-Biotin interactions), allowing for a colorimetric reaction to ensue upon substrate addition. When the substrate TMB (3, 3', 5, 5'-Tetramethylbenzidine) is added, the reaction catalyzed by peroxidase yields a blue color that is representative of the antigen concentration. Upon sufficient color development, the reaction can be terminated through addition of Stop Solution (2 N Sulfuric Acid) where the color of the solution will turn yellow. The absorbance of each well can then be read by a spectrophotometer, allowing for generation of a standard curve and subsequent determination of protein concentration