Shirahama K, Yazaki Y, Sakano K, Wada Y, Ohsumi Y
Department of Biology, Graduate School of Arts and Sciences, University of Tokyo, Japan.
Plant Cell Physiol. 1996 Dec;37(8):1090-3. doi: 10.1093/oxfordjournals.pcp.a029058.
We studied physiological roles of the yeast vacuole in the phosphate metabolism using 31P-in vivo nuclear magnetic resonance (NMR) spectroscopy. Under phosphate starvation wild-type yeast cells continued to grow for two to three generations, implying that wild-type cells contain large phosphate pool to sustain the growth. During the first four hours under the phosphate starved condition, the cytosolic phosphate level was maintained almost constant, while the vacuolar pool of phosphate decreased significantly. 31P-NMR spectroscopy on the intact cells and perchloric acid (PCA) extracts showed that drastic decrease of polyphosphate took place during this phase. In contrast, delta slp1 cells, which were defective in the vacuolar compartment, thus lacked polyphosphate, ceased their growth immediately when they faced to phosphate starvation. Taken together, we conclude that vacuolar polyphosphate provides an active pool for phosphate and is mobilized to cytosol during phosphate starvation and sustained cell growth for a couple rounds of cell cycle.
我们使用³¹P体内核磁共振（NMR）光谱研究了酵母液泡在磷酸盐代谢中的生理作用。在磷酸盐饥饿条件下，野生型酵母细胞继续生长两到三代，这意味着野生型细胞含有大量的磷酸盐储备以维持生长。在磷酸盐饥饿条件下的前四个小时，胞质磷酸盐水平几乎保持恒定，而液泡中的磷酸盐储备显著下降。对完整细胞和高氯酸（PCA）提取物进行的³¹P-NMR光谱显示，在此阶段多聚磷酸盐急剧减少。相比之下，液泡区室有缺陷、因此缺乏多聚磷酸盐的delta slp1细胞在面临磷酸盐饥饿时立即停止生长。综上所述，我们得出结论，液泡多聚磷酸盐为磷酸盐提供了一个活性储备库，并且在磷酸盐饥饿期间被转运到细胞质中，以维持细胞在几轮细胞周期中的生长。
