Macropinocytosis, an evolutionarily conserved endocytic pathway, mediates nonselective bulk uptake of extracellular fluid. It is the primary route for axenic cells to obtain nutrients and has also emerged as a nutrient-scavenging pathway for mammalian cells. How cells adjust macropinocytic activity in various physiological or developmental contexts remains to be elucidated. We discovered that, in cells, the transcription factors Hbx5 and MybG form a functional complex in the nucleus to maintain macropinocytic activity during the growth stage. In contrast, during starvation-induced multicellular development, the transcription factor complex undergoes nucleocytoplasmic shuttling in response to oscillatory cyclic adenosine 3′,5′-monophosphate (cAMP) signals, which leads to increased cytoplasmic retention of the complex and progressive downregulation of macropinocytosis. Therefore, by coupling macropinocytosis-related gene expression to the cAMP oscillation system, which facilitates long-range cell-cell communication, the dynamic translocation of the Hbx5-MybG complex orchestrates a population-level adjustment of macropinocytic activity to adapt to changing environmental conditions.

中文翻译：

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盘基网柄菌中的转录因子复合物能够在生长到发育的过渡过程中实现巨胞饮作用的适应性变化

巨胞饮作用是一种进化上保守的内吞途径，介导细胞外液的非选择性大量摄取。它是无菌细胞获取营养的主要途径，也已成为哺乳动物细胞的营养清除途径。细胞如何在各种生理或发育环境中调节巨胞饮活性仍有待阐明。我们发现，在细胞中，转录因子 Hbx5 和 MybG 在细胞核中形成功能复合物，以维持生长阶段的巨胞饮活性。相反，在饥饿诱导的多细胞发育过程中，转录因子复合物响应振荡环腺苷 3',5'-单磷酸 (cAMP) 信号而经历核细胞质穿梭，导致复合物的细胞质保留增加和巨胞饮作用逐渐下调。因此，通过将巨胞饮作用相关基因表达与促进长程细胞间通讯的 cAMP 振荡系统耦合，Hbx5-MybG 复合物的动态易位协调了巨胞饮活动的群体水平调整，以适应不断变化的环境条件。