Characterization of two receptors for TRAIL1

Abstract
Two receptors for TRAIL, designated TRAIL‐R2 and TRAIL‐R3, have been identified. Both are members of the tumor necrosis factor receptor family. TRAIL‐R2 is structurally similar to the death‐domain‐containing receptor TRAIL‐R1 (DR‐4), and is capable of inducing apoptosis. In contrast, TRAIL‐R3 does not promote cell death. TRAIL‐R3 is highly glycosylated and is membrane bound via a putative phosphatidylinositol anchor. The extended structure of TRAIL‐R3 is due to the presence of multiple threonine‐, alanine‐, proline‐ and glutamine‐rich repeats (TAPE repeats). TRAIL‐R2 shows a broad tissue distribution, whereas the expression of TRAIL‐R3 is restricted to peripheral blood lymphocytes (PBLs) and skeletal muscle. All three TRAIL receptors bind TRAIL with similar affinity, suggesting a complex regulation of TRAIL‐mediated signals.