Wang Xiaofeng, Ni Weimin, Ge Xiaochun, Zhang Jiejin, Ma Hong, Cao Kaiming
1State Key Laboratory of Genetic Engineering, Department of Biochemistry and Molecular Biology, School of Life Sciences, Fudan University, Shanghai, 200433, China.
Cell Res. 2006 May;16(5):489-98. doi: 10.1038/sj.cr.7310060.
The ASK1 (ARABIDOPSIS SKP1-LIKE) protein is a critical component of the SCF (Skp1-Cullin-F box protein) ubiquitin ligase complexes that recruit target proteins for degradation by the 26S proteosome. To investigate proteins that are affected by the ASK1-mediated proteolysis pathway in Arabidopsis flowers, we compared the proteomes of the Arabidopsis wild type and ask1 mutant flower buds using two-dimensional electrophoresis (2-DE). Ten protein spots with higher or lower abundance in the ask1 mutant flowers compared to wild type flowers were excised and subjected to further mass spectrometry (MS) analysis. The results showed that they were proteins involved in photomorphogenesis, circadian oscillation, post-translation process, stress-responses and cell expansion or elongation, suggesting that those processes were affected in the ask1 mutant. The transcript levels of these genes were also compared based on the Affymetrix gene chip microarray data. No significant difference was observed for most of the genes, suggesting that the proteins with elevated levels of accumulation in the ask1 mutant could be candidate targets regulated by an ASK1-mediated proteolysis pathway. These results help to elucidate the pleiotropic functions of ASK1 in Arabidopsis developmental processes and also demonstrate the importance and necessity of studying protein levels with respect to gene functions.
ASK1（拟南芥SKP1样）蛋白是SCF（Skp1- Cul1 - F盒蛋白）泛素连接酶复合体的关键组成部分，该复合体招募靶蛋白以便被26S蛋白酶体降解。为了研究拟南芥花中受ASK1介导的蛋白水解途径影响的蛋白质，我们使用二维电泳（2-DE）比较了拟南芥野生型和ask1突变体花芽的蛋白质组。与野生型花相比，ask1突变体花中丰度较高或较低的10个蛋白点被切除，并进行进一步的质谱（MS）分析。结果表明，它们是参与光形态建成、昼夜节律振荡、翻译后过程、应激反应以及细胞扩张或伸长的蛋白质，这表明这些过程在ask1突变体中受到了影响。还基于Affymetrix基因芯片微阵列数据比较了这些基因的转录水平。大多数基因未观察到显著差异，这表明在ask1突变体中积累水平升高的蛋白质可能是由ASK1介导的蛋白水解途径调控的候选靶标。这些结果有助于阐明ASK1在拟南芥发育过程中的多效性功能，也证明了就基因功能而言研究蛋白质水平的重要性和必要性。
