Energetic costs of protein synthesis do not differ between red- and white-blooded Antarctic notothenioid fishes
Energetic costs of protein synthesis do not differ between red- and white-blooded Antarctic notothenioid fishes
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DOI：
10.1016/j.cbpa.2015.05.026
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发表时间：
2015-09-01
影响因子：
2.3
通讯作者：
O'Brien, Kristin M.
中科院分区：
文献类型：
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作者：
Lewis, Johanne M.;Grove, Theresa J.;O'Brien, Kristin M.
南极冰鱼亚目（冰鱼科）缺乏氧结合蛋白血红蛋白（Hb）， 16种冰鱼中有6种缺乏心室肌红蛋白（Mb）。作为铁中心蛋白，Hb和Mb可以促进活性氧（ROS）的形成，从而破坏生物大分子。与此一致的是，我们之前的研究表明，与血红的南极鱼相比，冰鱼的氧化肌肉中的氧化蛋白质和脂质水平较低。由于氧化蛋白通常被20S蛋白酶体降解，必须重新合成，我们假设冰鱼的蛋白质合成率比红血南极鱼低，从而降低了蛋白质合成的能量成本，并有利于Hb和Mb的损失。在分离的肝细胞和心肌细胞中测量了用于蛋白质合成的氧气消耗的比例，这些细胞的Hb和心肌Mb表达不同。蛋白质合成的速度和蛋白质合成的能量成本在物种之间都没有差异，这表明与冰鱼相比，红血物种不会以更高的速度降解和替换氧化修饰的蛋白质，而是保持更高水平的氧化蛋白质。(C) 2015爱思唯尔公司版权所有。
Antarctic icefishes (Family Channichthyidae) within the suborder Notothenioidei lack the oxygen-binding protein hemoglobin (Hb), and six of the 16 species of icefishes lack myoglobin (Mb) in heart ventricle. As iron-centered proteins, Hb and Mb can promote the formation of reactive oxygen species (ROS) that damage biological macromolecules. Consistent with this, our previous studies have shown that icefishes have lower levels of oxidized proteins and lipids in oxidative muscle compared to red-blooded notothenioids. Because oxidized proteins are usually degraded by the 20S proteasome and must be resynthesized, we hypothesized that rates of protein synthesis would be lower in icefishes compared to red-blooded notothenioids, thereby reducing the energetic costs of protein synthesis and conferring a benefit to the loss of Hb and Mb. Rates of protein synthesis were quantified in hearts, and the fraction of oxygen consumption devoted to protein synthesis was measured in isolated hepatocytes and cardiomyocytes of notothenioids differing in the expression of Hb and cardiac Mb. Neither rates of protein synthesis nor the energetic costs of protein synthesis differed among species, suggesting that red-blooded species do not degrade and replace oxidatively modified proteins at a higher rate compared to icefishes but rather, persist with higher levels of oxidized proteins. (C) 2015 Elsevier Inc. All rights reserved.