RESUMO
The Hippo pathway effectors Yes-associated protein 1 (YAP) and its homolog TAZ are transcriptional coactivators that control gene expression by binding to TEA domain (TEAD) family transcription factors. The YAP/TAZ-TEAD complex is a key regulator of cancer-specific transcriptional programs, which promote tumor progression in diverse types of cancer, including breast cancer. Despite intensive efforts, the YAP/TAZ-TEAD complex in cancer has remained largely undruggable due to an incomplete mechanistic understanding. Here, we report that nuclear phosphoinositides function as cofactors that mediate the binding of YAP/TAZ to TEADs. The enzymatic products of phosphoinositide kinases PIPKIα and IPMK, including phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) and phosphatidylinositol 3,4,5-trisphosphate (P(I3,4,5)P3), bridge the binding of YAP/TAZ to TEAD. Inhibiting these kinases or the association of YAP/TAZ with PI(4,5)P2 and PI(3,4,5)P3 attenuates YAP/TAZ interaction with the TEADs, the expression of YAP/TAZ target genes, and breast cancer cell motility. Although we could not conclusively exclude the possibility that other enzymatic products of IPMK such as inositol phosphates play a role in the mechanism, our results point to a previously unrecognized role of nuclear phosphoinositide signaling in control of YAP/TAZ activity and implicate this pathway as a potential therapeutic target in YAP/TAZ-driven breast cancer.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal , Neoplasias da Mama , Transdução de Sinais , Transativadores , Fatores de Transcrição , Proteínas de Sinalização YAP , Humanos , Neoplasias da Mama/metabolismo , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Fatores de Transcrição/metabolismo , Fatores de Transcrição/genética , Proteínas de Sinalização YAP/metabolismo , Proteínas de Sinalização YAP/genética , Feminino , Transativadores/metabolismo , Transativadores/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Fosfoproteínas/metabolismo , Fosfoproteínas/genética , Proteínas com Motivo de Ligação a PDZ com Coativador Transcricional/metabolismo , Linhagem Celular Tumoral , Fosfatos de Fosfatidilinositol/metabolismo , Fosfatidilinositol 4,5-Difosfato/metabolismo , Fosfatidilinositóis/metabolismo , Regulação Neoplásica da Expressão Gênica , Proteínas de Ligação a DNA/metabolismo , Proteínas de Ligação a DNA/genética , Núcleo Celular/metabolismo , Fosfotransferases (Aceptor do Grupo Álcool)/metabolismo , Fosfotransferases (Aceptor do Grupo Álcool)/genética , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/genéticaRESUMO
Phosphatidylinositol (PI) lipids control critical biological processes, so aberrant biosynthesis often leads to disease. As a result, the capability to track the production and localization of these compounds in cells is vital for elucidating their complex roles. Herein, we report the design, synthesis, and application of clickable myo-inositol probe 1 a for bioorthogonal labeling of PI products. To validate this platform, we initially conducted PI synthase assays to show that 1 a inhibits PI production in vitro. Fluorescence microscopy experiments next showed probe-dependent imaging in T-24 human bladder cancer and Candida albicans cells. Growth studies in the latter showed that replacement of myo-inositol with probe 1 a led to an enhancement in cell growth. Finally, fluorescence-based TLC analysis and mass spectrometry experiments support the labeling of PI lipids. This approach provides a promising means for tracking the complex biosynthesis and trafficking of these lipids in cells.