Probing the role of AKAPs in breast cancer using stapled peptide inhibitors

描述（由申请人提供）：蛋白激酶超家族是人类基因组中最大的蛋白类之一。激酶调节与发育和疾病（包括癌症）有关的关键信号传导过程。小分子激酶调节剂已成为重要的治疗工具，并且通常靶向这些酶的结构和功能上最保守的区域中的催化结构域。虽然这些工具提供了对激酶活性的巨大洞察，但由于激酶之间的高度结构保守性，特异性一直难以实现。此外，许多蛋白质：调节激酶活性的蛋白质相互作用是通过使用小分子方法难以破坏的螺旋相互作用介导的。作为一种手段来规避这些问题，我建议开发合成修饰的螺旋，将被应用为调查工具，以介导蛋白质：蛋白质相互作用的激酶调控事件。作为理解激酶调节的模型，cAMP依赖性蛋白激酶A（PKA）将被用作探测激酶调节的范例。PKA具有广泛的底物特异性，因此活性部分地通过与称为A激酶调节蛋白（AKAP）的各种蛋白质的相互作用在特定靶子集附近的细胞内定位来调节。AKAP直接与调节亚基相互作用以定位四聚体复合物。单核苷酸多态性（SNP）分析显示，AKAP蛋白D-AKAP 2的PKA结合区（AKB）中的单个氨基酸变化与多种疾病状态相关，包括家族性乳腺癌。将设计合成稳定的同种型特异性肽以探测AKAP介导的与PKA的R亚基的相互作用。通过蛋白磷酸化和表达变化监测的细胞信号传导事件将通过质谱法进行比较分析，以揭示非癌性和乳腺上皮癌细胞系中的亚型特异性激酶活性。这将被用作研究癌症模型中改变的激酶信号传导的基础。

DESCRIPTION (provided by applicant): The protein kinase superfamily is one of the largest protein classes in the human genome. Kinases regulate key signaling processes that have been implicated in development and disease, including cancer. Small molecule kinase modulators have become important therapeutic tools and often target catalytic domains that are among the most structurally and functionally conserved regions of these enzymes. While these tools have provided tremendous insight into kinase activity, specificity has been difficult to achieve due to the high degree of structural conservation among kinases. Further, many protein: protein interactions that regulate kinase activity are mediated through -helical interactions that are difficult to disrupt using small molecule approaches. As a means to circumvent these problems, I propose to develop synthetically modified -helices that will be applied as investigative tools to mediate protein: protein interaction events involved in kinase regulation. As a model for understanding kinase regulation, cAMP-dependent Protein Kinase A (PKA) will be used as a paradigm for probing kinase regulation. PKA has broad substrate specificity, so activity is partly regulated by intracellular localization near specific target subsets via interactions with a diverse set of proteins called A Kinase Anchoring proteins (AKAPs). AKAPs interact directly with the regulatory subunits to localize the tetrameric complex. Single nucleotide polymorphism (SNP) analysis has revealed that single amino acid changes in the PKA Binding Region (AKB) of the AKAP protein D-AKAP2 is linked to a variety of disease states, including familial breast cancer. Synthetically stabilized, isoform-specific peptides will be designed to probe AKAP- mediated interactions with the R-subunits of PKA. Cell signaling events, as monitored by protein phosphorylation and expression changes, will be comparatively analyzed by mass spectrometry to uncover isoform-specific kinase activity in non-cancerous and mammary epithelial cancer cell lines. This will be used as a foundation for studying altered kinase signaling in cancer models.