Differential Regulation of the TRAIL Death Receptors DR4 and DR5 by the Signal Recognition Particle

AUTOR(ES)

Ren, Yan-Guo

FONTE

The American Society for Cell Biology

RESUMO

TRAIL (TNF-related apoptosis-inducing ligand) death receptors DR4 and DR5 facilitate the selective elimination of malignant cells through the induction of apoptosis. From previous studies the regulation of the DR4 and DR5 cell-death pathways appeared similar; nevertheless in this study we screened a library of small interfering RNA (siRNA) for genes, which when silenced, differentially affect DR4- vs. DR5-mediated apoptosis. These experiments revealed that expression of the signal recognition particle (SRP) complex is essential for apoptosis mediated by DR4, but not DR5. Selective diminution of SRP subunits by RNA interference resulted in a dramatic decrease in cell surface DR4 receptors that correlated with inhibition of DR4-dependent cell death. Conversely, SRP silencing had little influence on cell surface DR5 levels or DR5-mediated apoptosis. Although loss of SRP function in bacteria, yeast and protozoan parasites causes lethality or severe growth defects, we observed no overt phenotypes in the human cancer cells studied—even in stable cell lines with diminished expression of SRP components. The lack of severe phenotype after SRP depletion allowed us to delineate, for the first time, a mechanism for the differential regulation of the TRAIL death receptors DR4 and DR5—implicating the SRP complex as an essential component of the DR4 cell-death pathway.

Documentos Relacionados

• Dimerization interfaces formed between the DNA binding domains determine the cooperative binding of RXR/RAR and RXR/TR heterodimers to DR5 and DR4 elements.
• Increased Expression of Death Receptors 4 and 5 Synergizes the Apoptosis Response to Combined Treatment with Etoposide and TRAIL
• Genetic variants of complement component 3 (C3) in DR4 positive and DR4 negative rheumatoid arthritis.
• Structure of the signal recognition particle by electron microscopy.
• HLA DR4 and rheumatoid arthritis in Japanese people.