Profile substrates and inhibitors of protein lysine methyltransferase

描述(由申请人提供)：蛋白质甲基转移酶通过不同的翻译后甲基化来协调表观遗传途径。该反应是通过蛋白质赖氨酸甲基转移酶(PKMT)将腺苷-L-蛋氨酸(SAM)的甲基转移到底物的特定赖氨酸(S)上来进行的。这一过程中的错误被认为与许多癌症有关。越来越多的证据表明，表观遗传多样性需要PKMT对组蛋白和非组蛋白进行甲基化。然而，很少有工具可以明确地描述指定的PKMT的非组蛋白靶点，特别是在癌细胞增殖的背景下。此外，很少有PKMT抑制剂可以用来破坏PKMT的功能。这种情况严重阻碍了我们开发以PKMT为新靶点的癌症治疗策略的能力。我们的长期目标是阐明和操纵PKMT在癌症诊断和治疗中的生物学功能。这项提案的目的是开发新技术，并将其应用于识别与癌症相关的PKMT的蛋白质靶点和小分子抑制剂。了解PKMT的靶点将是全面理解PKMT表观遗传功能的关键一步。更重要的是，可以检测PKMT的抑制剂对癌症的治疗效果。为了描述PKMT的靶标，我们设想这种酶可以被改造成利用SAM类似的辅因子，从而用不同的化学基团标记其靶标。然后，不同的修改将得到各自记者的认可。同时，将采用一种新的高通量筛选方法来鉴定PKMT的抑制剂。我们的靶标分析和抑制剂识别方法的影响因其对其他PKMT的普遍适用性而进一步加强。

DESCRIPTION (provided by applicant): Protein methyltransferases orchestrate epigenetic pathways through diverse posttranslational methylation. The reaction is carried out by protein lysine methyltransferases (PKMTs) through transferring the methyl group of SAM (S-adenosyl-L- methionine) to specific lysine(s) of substrates. The errors in the process have been implicated in many cancers. Accumulated evidence indicated that epigenetic diversity requires PKMTs to methylate histones and nonhistone proteins. However, few tools are available to unambiguously profile the nonhistone targets of designated PKMTs, particularly in context of proliferating cancer cells. In addition, few PKMT inhibitors are available to disrupt PKMT functions. Such situations significantly hinder our capability to develop cancer-therapeutic strategies with the PKMTs as novel targets. Our long-term goal is to elucidate and manipulate the biological functions of PKMT for cancer diagnosis and treatment. The objective of this proposal is to develop novel technologies and apply them to identify protein targets and small-molecule inhibitors of a cancer-relevant PKMT. Knowing the targets of the PKMT will be a key step toward fully understanding the epigenetic functions of the PKMT. More importantly, the inhibitors of the PKMT can be examined for their cancer-therapeutic effects. To profile the targets of the PKMT, we envision that the enzyme can be engineered to utilize SAM analogue cofactors and thus label its targets with distinct chemical groups. The distinct modifications will then be recognized by respective reporters. Meanwhile, a novel high-throughput screening approach will be implemented to identify the inhibitors of the PKMT. The impact of our target-profiling and inhibitor-identifying methods is further strengthened by their general applicability to other PKMTs.