Needle Danielle, Bauer Katarina, Mattocks Richard R, Miller Gregory J
The Department of Chemistry, The Catholic University of America, Washington, DC, USA.
Methods Mol Biol. 2025;2972:171-187. doi: 10.1007/978-1-0716-4799-8_13.
Inositol phosphate and pyrophosphate kinases (InsPKs) regulate cellular signaling by phosphorylating inositol phosphates, which play key roles in diverse physiological processes from insulin signaling to cell proliferation. Here, we review the structural biology of these enzymes and our understanding of their distinctive architectures. InsPKs can be classified into two structural families, which consist of InsPKs and other enzymes: the protein kinase-like and ATP-Grasp, each with distinct catalytic features. While crystal structures have been determined for representative catalytic domains through the InsPK synthetic pathways, structural information remains limited to these domains, with little information to guide our understanding of regulatory mechanisms or architectures of multidomain InsPKs. Here, we review the evolution of InsPK classification from early substrate-based naming to modern structural family groupings. We highlight how structural insights have revealed relationships between seemingly unrelated enzymes and what can be understood about InsPKs from features they share with other enzymes. We also provide an overview of the decision points in InsPK structural biology, from protein engineering and expression to crystallization, emphasizing how choices at each stage impact both the likelihood of success and the biological relevance of the results. We discuss the tools and recent advances, such as AlphaFold structure predictions, which have provided new insights into previously intractable regions of InsPKs and offer guidance for future exploration of these kinases.
肌醇磷酸和焦磷酸激酶（InsPKs）通过磷酸化肌醇磷酸来调节细胞信号传导，肌醇磷酸在从胰岛素信号传导到细胞增殖的各种生理过程中发挥关键作用。在此，我们综述这些酶的结构生物学以及我们对其独特结构的理解。InsPKs可分为两个结构家族，这两个家族由InsPKs和其他酶组成：蛋白激酶样家族和ATP结合蛋白家族，每个家族都有独特的催化特征。虽然已经通过InsPK合成途径确定了代表性催化结构域的晶体结构，但结构信息仅限于这些结构域，几乎没有信息可指导我们理解多结构域InsPKs的调控机制或结构。在此，我们综述了InsPK分类从早期基于底物的命名到现代结构家族分组的演变。我们强调结构见解如何揭示了看似不相关的酶之间的关系，以及从InsPKs与其他酶共有的特征中可以了解到什么。我们还概述了InsPK结构生物学中的决策点，从蛋白质工程和表达到结晶，强调每个阶段的选择如何影响成功的可能性和结果的生物学相关性。我们讨论了工具和最新进展，如AlphaFold结构预测，这些工具为InsPKs以前难以处理的区域提供了新的见解，并为未来探索这些激酶提供了指导。
