Adachi Sumiko, Uchimiya Hirofumi, Umeda Masaaki
Graduate School of Biological Sciences, Nara Institute of Science and Technology, Takayama 8916-5, Ikoma, Nara, 630-0101 Japan.
Plant Cell Physiol. 2006 Dec;47(12):1683-6. doi: 10.1093/pcp/pcl034. Epub 2006 Nov 11.
The eukaryotic cell cycle is controlled by cyclin-dependent kinases (CDKs). Plants possess six types of CDK, among which the B-type CDK (CDKB) is expressed specifically from the late S- to the M-phase. We demonstrate that the expression of Arabidopsis CDKB2 is under the control of the protein degradation machinery. beta-Glucuronidase fused to a putative PEST motif of CDKB2 was unstable in tobacco Bright Yellow-2 cells and Arabidopsis plants, and its degradation was arrested by the proteasome inhibitor MG132. We propose that the abundance of CDKB2 protein is regulated not only at the transcriptional level, but also through proteasome-mediated protein degradation.
真核细胞周期受细胞周期蛋白依赖性激酶（CDK）控制。植物有六种类型的CDK，其中B型CDK（CDKB）仅在S期晚期到M期表达。我们证明拟南芥CDKB2的表达受蛋白质降解机制的控制。与CDKB2假定的PEST基序融合的β-葡萄糖醛酸酶在烟草亮黄-2细胞和拟南芥植物中不稳定，其降解被蛋白酶体抑制剂MG132阻断。我们提出，CDKB2蛋白的丰度不仅在转录水平受到调节，还通过蛋白酶体介导的蛋白质降解进行调节。
