Fas receptor

The Fas receptor ( FasR ), and Fas, CD95 ( cluster of differentiation 95) or the APO -1 ( apoptosis antigen 1 ) is a TNF receptor by ligand binding to the death (apoptosis ) of the respective trigger cell.

FasR is a so-called type I transmembrane protein, which has two cysteine-rich repeat units in the extracellular domain protein. These structures are characteristic of TNF receptors. Fas - receptor is expressed in various cells, including activated B - cells and T - cells, in hepatocytes and epithelial cells of the ovary. Tumor cells expressing large amounts of the receptor part on their cell surface. It has a size of 45 kDa.

The receptor was discovered in 1989 by Peter Krammer and employees, the corresponding ligand was isolated in 1993.

Function

The ligand of the Fas receptor is called and FasL is expressed in few cell types, including for example on activated T cells. Most preferably, the functions of FasR and its ligands have been studied in the immune system, particularly in the B and T cells. Binding of the ligand to the Fas receptor an apoptosis program AICD ( activation-induced cell death ) is triggered, leading to the death of the cell. In this way about self - reactive lymphocytes can be kept in check. Error in the function of the Fas receptor or Fas ligand can lymphoproliferative diseases, such as autoimmune diseases lead.

The binding of FasL to FasR leads to trimerization of the previously present as monomers FasR molecules. The formation of trimers is essential for the function of the receptor. Transmits the signal of the FasR trimer by intracellular death domains ( engl. death domains) that mediate the formation of multiprotein complex DISC ( death- inducing signaling complex). This ultimately leads to the activation of caspases, which are responsible for the suicide program of the cell.