Ca²⁺/calmodulin-dependent protein kinase II (CaMKII) is a highly conserved serine/threonine kinase that is ubiquitously expressed throughout the human body. Specialized isoforms of CaMKII play key roles in neuronal and cardiac signaling. The distinctive holoenzyme architecture of CaMKII, with 12–14 kinase domains attached by flexible linkers to a central hub, poses formidable challenges for structural characterization. Nevertheless, progress in determining the structural mechanisms underlying CaMKII functions has come from studying the kinase domain and the hub separately, as well as from a recent electron microscopic investigation of the intact holoenzyme. In this review, we discuss our current understanding of the structure of CaMKII. We also discuss the intriguing finding that the CaMKII holoenzyme can undergo activation-triggered subunit exchange, a process that has implications for the potentiation and perpetuation of CaMKII activity.

中文翻译：

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Ca2+/钙调蛋白依赖性蛋白激酶 II (CaMKII) 调控的结构性见解。

钙²⁺钙调蛋白依赖性蛋白激酶 II (CaMKII) 是一种高度保守的丝氨酸/苏氨酸激酶，在整个人体中普遍表达。CaMKII 的特殊亚型在神经元和心脏信号传导中起关键作用。CaMKII 独特的全酶结构，具有 12-14 个激酶结构域，通过灵活的接头连接到中心枢纽，对结构表征提出了巨大的挑战。然而，确定 CaMKII 功能的结构机制的进展来自分别研究激酶结构域和中枢，以及最近对完整全酶的电子显微镜研究。在这篇综述中，我们讨论了我们目前对 CaMKII 结构的理解。我们还讨论了一个有趣的发现，即 CaMKII 全酶可以进行激活触发的亚基交换，