Posttranslational mechanisms play a key role in modifying the abundance and function of cellular proteins. Among these, modification by advanced glycation end products (AGEs) has been shown to accumulate during aging and age-associated diseases but specific protein targets and functional consequences remain largely unexplored. Here, we devised a proteomic strategy to identify specific sites of carboxymethyllysine (CML) modification, one of the most abundant AGEs. We identified over 1000 sites of CML modification in mouse and primary human cells treated with the glycating agent glyoxal. By using quantitative proteomics, we found that protein glycation triggers a proteotoxic response and directly affects the protein degradation machinery. We show that glyoxal induces cell cycle perturbation in primary endothelial cells and that CML modification reduces acetylation of tubulins and impairs microtubule dynamics. Our data demonstrate the relevance of AGE modification for cellular function and pinpoint specific protein networks that might become compromised during aging.

中文翻译：

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羧甲基赖氨酸修饰在蛋白质上的定位位点揭示了其对蛋白稳定和细胞增殖的影响

翻译后机制在修饰细胞蛋白的丰度和功能中起关键作用。其中，高级糖基化终产物（AGEs）的修饰已显示出在衰老和与年龄相关的疾病中积累，但特定的蛋白质靶标和功能后果仍未得到充分探索。在这里，我们设计了一种蛋白质组学策略，以识别羧甲基赖氨酸（CML）修饰（最丰富的AGEs之一）的特定位点。我们在用糖化剂乙二醛处理过的小鼠和原代人细胞中鉴定了1000多个CML修饰位点。通过使用定量蛋白质组学，我们发现蛋白质糖基化会触发蛋白质毒性反应，并直接影响蛋白质降解机制。我们表明乙二醛在初级内皮细胞中诱导细胞周期扰动，而CML修饰减少微管蛋白的乙酰化并损害微管动力学。我们的数据证明了AGE修饰与细胞功能的相关性，并指出了可能在衰老过程中受损的特定蛋白质网络。