As members of the mitogen-activated protein kinase (MAPK) family, the c-Jun N-terminal kinases (JNKs) regulate cell responses to a wide range of extrinsic and intrinsic insults, including irradiation, reactive oxygen species (ROS), DNA damage, heat, bacterial antigens, and inflammatory cytokines. Particularly, JNK signaling regulates and promotes many important physiological processes that influence metabolic and tissue homeostasis, cell death/survival, and cell damage repair and ultimately impacts the lifespan of an organism. This diverse functionality causes a variety of tissue-specific and context-specific cellular responses, mediated by various cross talks between JNK and other cellular signaling pathways. Thus, highlighting its significance as a determinant of stress responses, JNK loss-of-function mutations have been implicated in a multitude of pathologies, including neurodegenerative diseases, diabetes, and cancer. Because JNK functions are specified in a context-dependent manner and can greatly vary, the underlying causes for these different outcomes remain largely unresolved despite the gained knowledge of many regulatory roles of JNK signaling during the past two decades. In Drosophila melanogaster, JNK signaling is conserved and required for immune responses, as well as the development for morphogenetic processes (embryonic dorsal closure and thorax closure). Therefore, Drosophila innate immunity provides the ideal model to understand the complex mechanisms underlying JNK activation and regulation. In the following, we review studies in Drosophila that highlight several mechanisms by which JNK signaling influences immunity and homeostasis.

作为有丝分裂原激活蛋白激酶（MAPK）家族的成员，c-Jun N端激酶（JNK）调节细胞对多种外在和内在损伤的反应，包括辐射，活性氧（ROS），DNA损伤，热，细菌抗原和炎性细胞因子。特别地，JNK信号传导调节并促进许多重要的生理过程，这些过程影响代谢和组织稳态，细胞死亡/存活以及细胞损伤修复，并最终影响生物体的寿命。这种不同的功能会导致多种组织特异性和背景特异性细胞应答，这些应答由JNK与其他细胞信号通路之间的各种串扰介导。因此，强调其作为压力反应决定因素的重要性，JNK功能丧失突变已涉及多种病理，包括神经退行性疾病，糖尿病和癌症。由于JNK功能是以上下文相关的方式指定的，并且可能会发生很大变化，因此尽管在过去的二十年中已了解到JNK信号的许多调节作用，但导致这些不同结果的根本原因仍未得到解决。在果蝇黑腹果蝇，JNK信号是保守的，是免疫反应以及形态发生过程（胚胎背侧闭合和胸腔闭合）发展所必需的。因此，果蝇先天免疫力提供了理想的模型，以了解JNK激活和调节的复杂机制。在下文中，我们回顾了果蝇中的研究，这些研究突出了JNK信号传导影响免疫力和体内平衡的几种机制。