Function and Mechanism of the Hippo-PI5P4K Axis for Growth Control

项目总结 我们的长期目标是破译PI5P4K驱动生长的分子机制，并阐明 它们的失调是如何导致乳腺肿瘤发生的。在这项建议中，我们将着手提供一个 全面了解新的信号网络，该网络对于整合代谢信息和 确定相关的蛋白质和途径如何相互作用来维持细胞内环境的稳定。 磷脂酰肌醇-5-磷酸4-激酶(PI5P4Ks)是一类非规范的磷脂酰肌醇-4-激酶家族 我们已经证明，这对于保持营养可获得性和燃料增长至关重要，但它们是如何受到监管的 他们自己在很大程度上是未知的。使用全面的体外激酶筛查，我们已经发现了核心 河马通路、MST1和MST2对PI5P4Ks和脂质的直接负调节作用 PI5P4Ks的底物PI-5-P与河马接头蛋白MOB1相互作用，进而影响活性 河马下游效应器的YAP。众所周知，河马途径对发育、生长非常重要 器官发生和这一途径的失调导致肿瘤的进展。 虽然PI5P4K与肿瘤生长有关，但PI5P4K到底是如何调控的还知之甚少。 此外，PI5P4K实际上是如何在生理条件和 像乳腺癌这样的病理背景是不完整的。为了回答这些重要的问题，我们将表演 目标如下： 在目标1中，我们将使用非常可行的生物物理和结构生物学来确定原子分辨率的细节 PI-5-P与MOB1的相互作用及PI-5-P如何调节MOB1与其他河马途径的结合 体外成分。 在目标2中，我们将研究PI5P4K的活性如何控制mob-lats复合体的激活 MST1/2下游，探索PI5P4K致瘤特性的一种潜在机制。 在目标3中，我们将通过一个小组的研究来确定PI5P4K-河马轴在乳腺癌中的生物学意义 TNBC细胞系、新的小鼠乳腺肿瘤模型和患者乳腺肿瘤样本。 该项目试图将定量结构生物学和分子细胞遗传学结合起来，以破译Pi-5- P调节HIPPO途径促进乳腺癌细胞的生长。鉴于PI5P4K是令人兴奋的“可用药”目标 对于乳腺癌，表征PI5P4K如何连接到河马通路揭示了一种可能的策略 未来的抗癌疗法。

PROJECT SUMMARY Our long-term goal is to decipher the molecular mechanisms underlying PI5P4K-driven growth and to elucidate how their dysregulation contributes to breast tumorigenesis. In this proposal, we will set out to provide a comprehensive understanding of a new signaling network that is critical to integrate metabolic information and determine how the related proteins and pathways interact to maintain cellular homeostasis. Phosphatidylinositol-5-phosphate 4-kinases (PI5P4Ks) are a family of non-canonical phosphoinositide kinases which we have shown to be critical for preserving nutrient availability and fuel growth yet how they are regulated themselves is largely unknown. Using a comprehensive in vitro kinase screen, we have discovered the core kinases of the Hippo pathway, MST1 and MST2 as direct negative regulators of the PI5P4Ks as well as the lipid substrate of the PI5P4Ks, PI-5-P to interact with the Hippo adaptor protein MOB1 which in turn effects the activity of the Hippo downstream effector YAP. The Hippo pathway is known to be important for development, growth and organogenesis, and dysregulation of this pathway leads to tumor progression. While PI5P4Ks have been linked to tumor growth, exactly how the PI5P4Ks are regulated is poorly understood. Furthermore, how the PI5P4Ks actually command cell growth under both physiological conditions and pathological contexts such as breast cancer is incomplete. To answer these important questions, we will perform the following Aims: In Aim 1 we will use very feasible biophysical and structural biology to determine atomic-resolution details of the interface between PI-5-P and MOB1 and quantitate how PI-5-P regulates MOB1 binding to other Hippo pathway components in vitro. In Aim 2 we will investigate how the activity of the PI5P4Ks control the activation of the MOB-LATS complex downstream of MST1/2, exploring one potential mechanism for PI5P4K tumorigenic properties. In Aim 3 we will establish the biological significance of the PI5P4K-Hippo axis in breast cancer using a panel of TNBC cell lines, novel mouse breast tumor models, and patient breast tumor samples. This project seeks to combine quantitative structural biology with molecular cell genetics to decipher how PI-5- P regulates the Hippo pathway for breast cancer cell growth. Given that PI5P4Ks are exciting ‘druggable’ targets for breast cancer, characterizing how PI5P4Ks connect to the Hippo pathway reveals a possible strategy for future anti-cancer therapies.