Recombinant Human FAS (TNFRSF6)-Fc Chimera (carrier-free)
Description
FAS was initially purified and cloned from SKW6.4 cells and a cDNA library of human T cell lymphoma KT-3 cells. FAS is a type I transmembrane protein and belongs to the TNF receptor superfamily. The extracellular region of FAS possesses three cystein-rich domains characteristic of the TNF superfamily, and the intracellular region which includes a death domain (DD). The binding of FASL to FAS induces conformational changes in FAS, leading to the recruitment of FADD and procaspase-8 and the assembly of the death-inducing signaling complex (DISC). Subsequently, caspase 8 is released from DISC and induces activation of caspase 3 and 7, proteolysis of cellular components, and apoptosis. Other biological effects not leading to apoptotic cell death have also been described. The interaction of FAS/FASL in immature dendritic cells (DCs) induces functional maturation. Fas-activated DCs increase the expression of MHC II, B7 co-stimulatory molecules, and DC-lysosome-associated membrane proteins (DC-LAMP), and secrete proinflammatory cytokines such as IL-1β and TNF-α. In addition, FAS/FASL interaction increases the production of chemokines in NK-T cells, and FASL acts as a survival factor for human CD34+ cells and increases their colony formation. Human activated PBMC and tumor cell lines express full-length mRNA and several mRNA FAS variants derived by alternative splicing; deletion of an exon encoding the transmembrane domain results in a soluble FAS molecule that blocks apoptosis. Patients with systemic lupus erythematosus show high levels of sFAS.