关键词: 昆虫, Ras蛋白, 自噬, 免疫防御, Ras-自噬轴

Abstract: Macroautophagy/autophagy, a self-protective mechanism for cellular recycling and degradation of the damaged components, is involved in host immune defense. Organisms initiate autophagy to maintain homeostasis during stresses such as pathogen invasion. Studies have shown that autophagy is primarily regulated by the Ras-Raf-MEK-ERK pathway, PI3K-AKT-mTOR pathway, AMPK pathway et al. These pathways are directly or indirectly controlled by upstream Ras protein. As a membrane-anchored protein, Ras plays a key role in cellular signal transduction and exerts dual regulatory effects on autophagy. Conversely, autophagy negatively regulates tumorigenesis induced by Ras mutations. Unlike mammals, insects lack adaptive immunity and rely mainly on innate immunity and conserved mechanisms such as autophagy to combat pathogen invasion. For example, in Drosophila melanogaster, Caenorhabditis elegans and Bombyx mori, upregulated expression levels of autophagy-related proteins have been reported during bacterial or viral infections to resist pathogens. However, research on the direct regulation of autophagy-mediated defense by Ras proteins in insects remains limited. Therefore, to clarify the key role of the Ras-autophagy axis and provide references for future studies, we summarized three aspects in this review: the molecular mechanisms by which Ras regulates autophagy, its role in insect immunity, and the collaborative network between insect autophagy and other defense mechanisms. The aim is to offer new perspectives for research on insect immunology, economic insect protection and pest control. Leveraging the unique advantages of insect models and technologies such as CRISPR, studies are expected to elucidate the regulatory mechanisms and functional thresholds of the Ras-autophagy axis, deepen our understanding of insect immune homeostasis, and pave the way for the targeted development of green pesticides in agriculture and the enhancement of stress resistance in economically valuable insects.

Key words: Insects, Ras protein, autophagy, immune defense, Ras-autophagy axis