The recombinant Human FAS protein is produced in vitro using a cell-free E. coli expression system (Full Length of Mature Protein). This system involves the in vitro synthesis of the protein using extracts from whole cells, which contain all the necessary components for transcription, translation, and post-translational modification. With the addition of supplementary cofactors, FAS proteins can be synthesized within a few hours. It's important to note that this system may not be suitable for large-scale production of recombinant proteins. The primary advantages of this system include the ability to synthesize proteins without cell culturing and the potential to express multiple proteins simultaneously.
FAS, also known as APO-1/CD95/TNFRSF6, is widely expressed in the thymus, liver, heart, and kidney. Interactions between FAS and FASL lead to the formation of a death-inducing signaling complex (DISC) in FAS-expressing cells, ultimately triggering apoptosis. Mutations in FAS receptors are associated with a loss of apoptotic signaling and have been linked to autoimmune lymphoproliferative syndrome (ALPS) type Ia, an autoimmune disorder. Moreover, FAS is considered a tumor suppressor as deletions and mutations of FAS have been observed in various cancers. Recent studies have demonstrated that FAS engagement can elicit nonapoptotic signals that promote inflammation and carcinogenesis.