Branched-chain amino acids (BCAAs) have been suggested to be particularly potent activators of Target of Rapamycin (TOR) signaling. Moreover, increased circulating BCAAs are associated with higher risk of insulin resistance and diabetes in both mice and humans, and with increased mortality in mice. However, it remains unknown if BCAAs play a more prominent role in longevity than do other essential amino acids (EAAs). To test for a more prominent role of BCAAs in lifespan and related traits in Drosophila, we restricted either BCAAs or a control group of three other EAAs, threonine, histidine and lysine (THK). BCAA restriction induced compensatory feeding, lipid accumulation, stress resistance and amelioration of age-related gut pathology. It also extended lifespan in a dietary-nitrogen-dependent manner. Importantly, the control restriction of THK had similar effects on these phenotypes. Our control diet was designed to have every EAA equally limiting for growth and reproduction, and our findings therefore suggest that the level of the most limiting EAAs in the diet, rather than the specific EAAs that are limiting, determines the response of these phenotypes to EAA restriction.

中文翻译：

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支链氨基酸对果蝇的寿命和衰老相关性状具有与其他必需氨基酸同等的作用。

已经提出支链氨基酸（BCAAs）是雷帕霉素靶标（TOR）信号转导的特别有效的活化剂。此外，增加的循环BCAAs与小鼠和人类的胰岛素抵抗和糖尿病的风险更高，并与小鼠的死亡率增加有关。然而，尚不知道BCAA在寿命中是否比其他必需氨基酸（EAA）发挥更大的作用。为了测试BCAA在果蝇的寿命和相关性状中的更重要作用，我们限制了BCAA或对照组的其他三个EAA，苏氨酸，组氨酸和赖氨酸（THK）。限制BCAA可以诱导代偿性摄食，脂质蓄积，抗逆性和改善与年龄有关的肠道病理。它还以饮食氮依赖的方式延长了寿命。重要的，THK的控制限制对这些表型有类似的影响。我们的对照饮食被设计成使每种EAA都同样限制生长和繁殖，因此我们的发现表明，饮食中限制性最强的EAA的水平而不是限制性的特定EAA决定了这些表型对EAA的反应限制。