Hypoxic induction of AKAP12 variant 2 shifts PKA-mediated protein phosphorylation to enhance migration and metastasis of melanoma cells
Hypoxic induction of AKAP12 variant 2 shifts PKA-mediated protein phosphorylation to enhance migration and metastasis of melanoma cells
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DOI：
10.1073/pnas.1418164112
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发表时间：
2015-04-07
影响因子：
11.1
通讯作者：
Giaccia, Amato J.
中科院分区：
文献类型：
--
作者：
Finger, Elizabeth C.;Castellini, Laura;Giaccia, Amato J.
支架蛋白是细胞内的关键枢纽，具有调节上游信号分子及其下游效应物以微调生物反应的能力。虽然它们可以作为信号分子和调节肿瘤发生的下游通路的关联的焦点，但关于肿瘤微环境如何影响支架蛋白的表达和活性知之甚少。这项研究表明，缺氧，一个共同的元素，实体瘤窝藏低氧水平，调节表达的支架蛋白AKAP 12（A-激酶锚蛋白12），AKAP 12 v2的特定变体，在转移性黑色素瘤。反过来，通过激酶组的磷酸化蛋白质组学和MS研究，我们证明了这种支架蛋白调节蛋白激酶A（PKA）介导的磷酸化事件在缺氧下的转变，导致肿瘤细胞的侵袭和迁移在体外的改变，以及转移在体内原位模型的黑色素瘤。从机制上讲，缺氧条件下AKAP 12依赖性PKA介导的磷酸化的转变是由于AKAP 12定位的变化与其两种变体之间的结构差异。重要的是，我们的工作定义了一种机制，通过这种机制，支架蛋白可以被肿瘤微环境调节，并进一步解释了肿瘤细胞如何通过一个单独的支架蛋白协调许多对肿瘤生长至关重要的关键信号通路。
Scaffold proteins are critical hubs within cells that have the ability to modulate upstream signaling molecules and their downstream effectors to fine-tune biological responses. Although they can serve as focal points for association of signaling molecules and downstream pathways that regulate tumorigenesis, little is known about how the tumor microenvironment affects the expression and activity of scaffold proteins. This study demonstrates that hypoxia, a common element of solid tumors harboring low oxygen levels, regulates expression of a specific variant of the scaffold protein AKAP12 (A-kinase anchor protein 12), AKAP12v2, in metastatic melanoma. In turn, through a kinome-wide phosphoproteomic and MS study, we demonstrate that this scaffolding protein regulates a shift in protein kinase A (PKA)-mediated phosphorylation events under hypoxia, causing alterations in tumor cell invasion and migration in vitro, as well as metastasis in an in vivo orthotopic model of melanoma. Mechanistically, the shift in AKAP12-dependent PKA-mediated phosphorylations under hypoxia is due to changes in AKAP12 localization vs. structural differences between its two variants. Importantly, our work defines a mechanism through which a scaffold protein can be regulated by the tumor microenvironment and further explains how a tumor cell can coordinate many critical signaling pathways that are essential for tumor growth through one individual scaffolding protein.