The eukaryotic genome is packaged into chromatin. The nucleosome, the basic unit of chromatin, is composed of DNA coiled around a histone octamer. Histones are among the longest-lived protein species in mammalian cells due to their thermodynamic stability and their associations with DNA and histone chaperones. Histone metabolism plays an integral role in homeostasis. While histones are largely stable, the degradation of histone proteins is necessary under specific conditions. Here, we review the physiological and cellular contexts that promote histone degradation. We describe specific known mechanisms that drive histone proteolysis. Finally, we discuss the importance of histone degradation and regulation of histone supply for organismal and cellular fitness.

中文翻译：

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减少、保留、回收：促进组蛋白降解的机制与稳定性和保留

真核基因组被包装到染色质中。核小体是染色质的基本单位，由缠绕在组蛋白八聚体周围的 DNA 组成。组蛋白是哺乳动物细胞中寿命最长的蛋白质种类之一，因为它们的热力学稳定性以及它们与 DNA 和组蛋白伴侣的关联。组蛋白代谢在体内平衡中起着不可或缺的作用。虽然组蛋白在很大程度上是稳定的，但组蛋白的降解在特定条件下是必要的。在这里，我们回顾了促进组蛋白降解的生理和细胞环境。我们描述了驱动组蛋白蛋白水解的特定已知机制。最后，我们讨论了组蛋白降解和组蛋白供应调节对机体和细胞适应性的重要性。