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Phosphatidylinositol 3-Kinase/Akt Mediates Integrin Signaling To Control RNA Polymerase I Transcriptional Activity

RNA polymerase I-mediated rRNA production is a key determinant of cell growth. Despite extensive studies, the signaling pathways that control RNA polymerase I-mediated rRNA production are not well understood. Here we provide original evidence showing that RNA polymerase I transcriptional activity is tightly controlled by integrin signaling. Furthermore, we show that a signaling axis consisting of focal adhesion kinase (FAK), Src, phosphatidylinositol 3-kinase (PI3K), Akt, and mTOR mediates the effect of integrin signaling on rRNA transcription. Additionally, we show that in kindlin-2 knockout mouse embryonic fibroblasts, overactivation of Ras, Akt, and Src can successfully rescue the defective RNA polymerase I activity induced by the loss of kindlin-2. Finally, through experiments with inhibitors of FAK, Src, and PI3K and rescue experiments in MEFs, we found that the FAK/Src/PI3K/Akt signaling pathway to control rRNA transcription is linear. Collectively, these studies reveal, for the first time, a pivotal role of integrin signaling in regulation of RNA polymerase I transcriptional activity and shed light on the downstream signaling axis that participates in regulation of this key aspect of cell growth.

Related Products

Cat.No. Product Name Information
S1006 Saracatinib (AZD0530) Saracatinib (AZD0530) is a potent Src inhibitor with IC50 of 2.7 nM in cell-free assays, and potent to c-Yes, Fyn, Lyn, Blk, Fgr and Lck; less active for Abl and EGFR (L858R and L861Q). Saracatinib induces autophagy. Phase 2/3.

Related Targets

Src Bcr-Abl