Institut de Biologie Paris-Seine, UMR 7238, CNRS, Sorbonne Université, 75005, Paris, France.
Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas-Universidad de Sevilla, 41092, Sevilla, Spain.
Free Radic Biol Med. 2023 Jul;203:58-68. doi: 10.1016/j.freeradbiomed.2023.04.004. Epub 2023 Apr 6.
Autophagy is a catabolic pathway that functions as a degradative and recycling process to maintain cellular homeostasis in most eukaryotic cells, including photosynthetic organisms such as microalgae. This process involves the formation of double-membrane vesicles called autophagosomes, which engulf the material to be degraded and recycled in lytic compartments. Autophagy is mediated by a set of highly conserved autophagy-related (ATG) proteins that play a fundamental role in the formation of the autophagosome. The ATG8 ubiquitin-like system catalyzes the conjugation of ATG8 to the lipid phosphatidylethanolamine, an essential reaction in the autophagy process. Several studies identified the ATG8 system and other core ATG proteins in photosynthetic eukaryotes. However, how ATG8 lipidation is driven and regulated in these organisms is not fully understood yet. A detailed analysis of representative genomes from the entire microalgal lineage revealed a high conservation of ATG proteins in these organisms with the remarkable exception of red algae, which likely lost ATG genes before diversification. Here, we examine in silico the mechanisms and dynamic interactions between different components of the ATG8 lipidation system in plants and algae. Moreover, we also discuss the role of redox post-translational modifications in the regulation of ATG proteins and the activation of autophagy in these organisms by reactive oxygen species.
自噬是一种分解代谢途径，作为一种降解和回收过程，在大多数真核细胞中维持细胞内稳态，包括光合生物如微藻。这个过程涉及到形成双层膜囊泡，称为自噬体，它吞噬待降解和回收的物质，并在溶酶体中进行。自噬是由一组高度保守的自噬相关（ATG）蛋白介导的，这些蛋白在自噬体的形成中起着基本作用。ATG8 泛素样系统催化 ATG8 与脂质磷脂酰乙醇胺的缀合，这是自噬过程中的一个必要反应。几项研究在光合真核生物中鉴定了 ATG8 系统和其他核心 ATG 蛋白。然而，这些生物中 ATG8 脂质化是如何被驱动和调节的，目前还不完全清楚。对整个微藻谱系的代表性基因组的详细分析表明，这些生物中的 ATG 蛋白高度保守，但红藻除外，红藻在多样化之前可能失去了 ATG 基因。在这里，我们在植物和藻类中，对 ATG8 脂质化系统的不同成分之间的机制和动态相互作用进行了计算机模拟研究。此外，我们还讨论了氧化还原翻译后修饰在调节 ATG 蛋白和活性氧物种激活自噬中的作用。
