The Gβγ-Src signaling pathway regulates TNF-induced necroptosis via control of necrosome translocation

Formation of multi-component signaling complex necrosomes is essential for tumor necrosis factor a (TNF)-induced programmed necrosis (also called necroptosis). However, the mechanisms of necroptosis are still largely unknown. We isolated a TNF-resistant L929 mutant cell line generated by retrovirus insertion and identified that disruption of the guanine nucleotide-binding protein gamma 10 (G gamma 10) gene is responsible for this phenotype. We further show that G gamma 10 is involved in TNF-induced necroptosis and G beta 2 is the partner of G gamma 10. Src is the downstream effector of G beta 2 gamma 10 in TNF-induced necroptosis because TNF-induced Src activation was impaired upon G gamma 10 knockdown. G gamma 10 does not affect TNF-induced activation of NF-kappa B and MAPKs and the formation of necrosomes, but is required for trafficking of necrosomes to their potential functioning site, an unidentified subcellular organelle that can be fractionated into heterotypic membrane fractions. The TNF-induced G beta gamma-Src signaling pathway is independent of RIP1/RIP3 kinase activity and necrosome formation, but is required for the necrosome to function.