GPCR - Linked RhoGEFs in Tumor Growth and Metastasis

项目摘要 G蛋白偶联受体（GPCRs）以其转换细胞外信息的能力而闻名 在激素、气味物质和肽中编码的蛋白质，通过调节 细胞中效应酶和通道的功能。然而，对人类癌症基因组的分析表明， 一些GPCR信号通路导致持续的信号，这些信号在病理环境中与肿瘤相关， 生长和转移。这些途径的共同特征是通过Dbl家族激活Rho GTP酶 Rho鸟嘌呤核苷酸交换因子（RhoGEF）。TrioC亚家族（由Trio、Kalirin和 p63 RhoGEF）被异源三聚体Gαq亚基直接激活，并与眼黑色素瘤密切相关 和白血病P-Rex亚家族（由P-Rex 1和2组成）被直接协同激活。 与GBetagamma和脂质PIP 3的相互作用，并在许多乳腺和前列腺肿瘤中过表达， 起到转移作用。因此，Trio和P-Rex 1/2已成为重要的化疗靶点。的事实 这些酶调节的分子和细胞机制迄今为止还不清楚， 这种理解阻碍了设计新的治疗方法的合理方法。通过确定 晶体学和cryo-EM结构的成员从这些RhoGEF亚家族，该提案旨在 定义激活的分子机制，并通过一系列功能测定来测试这些假设。 与此同时，我们将我们的功能分析扩展到模型细胞系统中，以了解组成性活性如何 异源三聚体G蛋白和GPCR促进癌细胞生长（如眼黑色素瘤）和转移（如眼黑色素瘤）。 在乳腺癌中）通过TrioC和P-Rex亚家族RhoGEF。通过了解监管的基础， RhoGEF活性的异源三聚体G蛋白在体外和相关的细胞环境中，我们将加速 发现新的生物学见解和新的治疗策略，可用于对抗癌症。

PROJECT SUMMARY G protein-coupled receptors (GPCRs) are well known for their ability to convert extracellular information encoded in hormones, odorants, and peptides into rapid changes in cellular homeostasis by modulating the function of effector enzymes and channels in the cell. However, analysis of human cancer genomes indicates that some GPCR signaling pathways lead to sustained signals that in pathological settings are linked to tumor growth and metastasis. A common feature of such pathways is the activation of Rho GTPases by Dbl family Rho guanine nucleotide exchange factors (RhoGEFs). The TrioC subfamily (composed of Trio, Kalirin, and p63RhoGEF) is directly activated by heterotrimeric Gαq subunits and is strongly implicated in ocular melanoma and leukemia. The P-Rex subfamily (composed of P-Rex1 and 2) is activated synergistically by direct interactions with GBetagamma and the lipid PIP3, and is overexpressed in many breast and prostate tumors where it plays a metastatic role. Trio and P-Rex1/2 have thus emerged as important chemotherapeutic targets. The fact that the molecular and cellular mechanisms underlying regulation of these enzymes are as of yet poorly understood prevents a rational approach to the design of novel therapeutic approaches. By determining crystallographic and cryo-EM structures of members from these RhoGEF subfamilies, this proposal seeks to define molecular mechanisms of activation and to test these hypotheses through a battery of functional assays. In parallel, we extend our functional analysis into model cell systems to understand how constitutively active heterotrimeric G proteins and GPCRs promote cancer cell growth (as in ocular melanoma) and metastasis (as in breast cancer) via TrioC and P-Rex subfamily RhoGEFs. By understanding the basis for regulation of RhoGEF activity by heterotrimeric G proteins both in vitro and in relevant cellular contexts, we will accelerate discovery of new biological insights and novel therapeutic strategies that can be used to combat cancer.