Center for Diabetes and Metabolic Diseases, Indiana University School of Medicine, Indianapolis, IN 46202, USA.
Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA.
Sci Signal. 2019 Dec 3;12(610):eaax0715. doi: 10.1126/scisignal.aax0715.
Deoxyhypusine synthase (DHPS) uses the polyamine spermidine to catalyze the hypusine modification of the mRNA translation factor eIF5A and promotes oncogenesis through poorly defined mechanisms. Because germline deletion of is embryonically lethal, its role in normal postnatal cellular function in vivo remains unknown. We generated a mouse model that enabled the inducible, postnatal deletion of specifically in postnatal islet β cells, which function to maintain glucose homeostasis. Removal of did not have an effect under normal physiologic conditions. However, upon development of insulin resistance, which induces β cell proliferation, deletion caused alterations in proteins required for mRNA translation and protein secretion, reduced production of the cell cycle molecule cyclin D2, impaired β cell proliferation, and induced overt diabetes. We found that hypusine biosynthesis was downstream of protein kinase C-ζ and was required for c-Myc-induced proliferation. Our studies reveal a requirement for DHPS in β cells to link polyamines to mRNA translation to effect facultative cellular proliferation and glucose homeostasis.
脱羟鸟氨酸合酶(DHPS)利用多胺亚精胺来催化 mRNA 翻译因子 eIF5A 的 hypusine 修饰,并通过尚未明确的机制促进肿瘤发生。由于 的种系缺失在胚胎期是致命的,因此其在正常出生后细胞功能中的作用在体内仍然未知。我们生成了一种小鼠模型,该模型可在出生后胰岛β细胞中诱导性地、出生后删除 ,β细胞的功能是维持葡萄糖稳态。在正常生理条件下,去除 没有影响。然而,在诱导β细胞增殖的胰岛素抵抗发展时, 删除导致翻译和蛋白质分泌所需的蛋白质发生改变,细胞周期分子细胞周期蛋白 D2 的产生减少,β细胞增殖受损,并导致明显的糖尿病。我们发现,脱羟鸟氨酸生物合成位于蛋白激酶 C-ζ 的下游,并且是 c-Myc 诱导增殖所必需的。我们的研究揭示了 DHPS 在β细胞中链接多胺与 mRNA 翻译以实现适应性细胞增殖和葡萄糖稳态的必要性。