Chattopadhyay M K, Murakami Y, Matsufuji S
Department of Biochemistry II, Jikei University School of Medicine, 3-25-8, Nishi-Shinbashi, Minato-ku, Tokyo 105-8461, Japan.
J Biol Chem. 2001 Jun 15;276(24):21235-41. doi: 10.1074/jbc.M010643200. Epub 2001 Mar 30.
The mechanism of the regulatory degradation of ornithine decarboxylase (ODC) by polyamines was studied in fission yeast, Schizosaccharomyces pombe. To regulate cellular spermidine experimentally, we cloned and disrupted S-adenosylmethionine decarboxylase gene (spe2) in S. pombe. The null mutant of spe2 was devoid of spermidine and spermine, accumulated putrescine, and contained a high level of ODC. Addition of spermidine to the culture medium resulted in rapid decrease in the ODC activity caused by the acceleration of ODC degradation, which was dependent on de novo protein synthesis. A fraction of ODC forming an inactive complex concomitantly increased. The accelerated ODC degradation was prevented either by knockout of antizyme gene or by selective inhibitors of proteasome. Thus, unlike budding yeast, mammalian type antizyme-mediated ODC degradation by proteasome is operating in S. pombe.
在裂殖酵母粟酒裂殖酵母中研究了多胺对鸟氨酸脱羧酶（ODC）的调节性降解机制。为了通过实验调节细胞内的亚精胺，我们克隆并破坏了粟酒裂殖酵母中的S-腺苷甲硫氨酸脱羧酶基因（spe2）。spe2的缺失突变体缺乏亚精胺和精胺，积累腐胺，并且含有高水平的ODC。向培养基中添加亚精胺导致ODC活性迅速下降，这是由于ODC降解加速所致，该过程依赖于从头合成蛋白质。一部分形成无活性复合物的ODC随之增加。通过敲除抗酶基因或使用蛋白酶体的选择性抑制剂可阻止ODC降解加速。因此，与芽殖酵母不同，哺乳动物类型的抗酶介导的蛋白酶体对ODC的降解在粟酒裂殖酵母中起作用。
