RESUMEN
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.
Asunto(s)
Proteínas Adaptadoras Transductoras de Señales , Neoplasias de la Mama , Transducción de Señal , Transactivadores , Factores de Transcripción , Proteínas Señalizadoras YAP , Humanos , Neoplasias de la Mama/metabolismo , Neoplasias de la Mama/genética , Neoplasias de la Mama/patología , Factores de Transcripción/metabolismo , Factores de Transcripción/genética , Proteínas Señalizadoras YAP/metabolismo , Proteínas Señalizadoras YAP/genética , Femenino , Transactivadores/metabolismo , Transactivadores/genética , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Proteínas Adaptadoras Transductoras de Señales/genética , Fosfoproteínas/metabolismo , Fosfoproteínas/genética , Proteínas Coactivadoras Transcripcionales con Motivo de Unión a PDZ/metabolismo , Línea Celular Tumoral , Fosfatos de Fosfatidilinositol/metabolismo , Fosfatidilinositol 4,5-Difosfato/metabolismo , Fosfatidilinositoles/metabolismo , Regulación Neoplásica de la Expresión Génica , Proteínas de Unión al ADN/metabolismo , Proteínas de Unión al ADN/genética , Núcleo Celular/metabolismo , Fosfotransferasas (Aceptor de Grupo Alcohol)/metabolismo , Fosfotransferasas (Aceptor de Grupo Alcohol)/genética , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Péptidos y Proteínas de Señalización Intracelular/genéticaRESUMEN
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.