The behaviour of Dictyostelium discoideum depends on nutrients¹. When sufficient food is present these amoebae exist in a unicellular state, but upon starvation they aggregate into a multicellular organism^2,3. This biology makes D. discoideum an ideal model for investigating how fundamental metabolism commands cell differentiation and function. Here we show that reactive oxygen species—generated as a consequence of nutrient limitation—lead to the sequestration of cysteine in the antioxidant glutathione. This sequestration limits the use of the sulfur atom of cysteine in processes that contribute to mitochondrial metabolism and cellular proliferation, such as protein translation and the activity of enzymes that contain an iron–sulfur cluster. The regulated sequestration of sulfur maintains D. discoideum in a nonproliferating state that paves the way for multicellular development. This mechanism of signalling through reactive oxygen species highlights oxygen and sulfur as simple signalling molecules that dictate cell fate in an early eukaryote, with implications for responses to nutrient fluctuations in multicellular eukaryotes.

盘基网柄菌的行为取决于养分¹。当存在足够的食物时，这些变形虫以单细胞状态存在，但在饥饿时它们聚集成多细胞生物^2,3。这种生物学使D. discoideum研究基本代谢如何控制细胞分化和功能的理想模型。在这里，我们表明由于营养限制而产生的活性氧导致抗氧化剂谷胱甘肽中的半胱氨酸螯合。这种隔离限制了半胱氨酸的硫原子在有助于线粒体代谢和细胞增殖的过程中的使用，例如蛋白质翻译和含有铁硫簇的酶的活性。硫的调节封存维持D. discoideum处于非增殖状态，为多细胞发育铺平了道路。这种通过活性氧物质发出信号的机制突出了氧和硫作为简单的信号分子，它们决定了早期真核生物的细胞命运，对多细胞真核生物对营养波动的反应具有重要意义。