Graduate School of Life Science and Division of Science, Hokkaido University, Sapporo, Japan.
Plant Signal Behav. 2010 Sep;5(9):1119-20. doi: 10.4161/psb.5.9.12479.
The ubiquitin/26S proteasome pathway plays a central role in the degradation of short-lived regulatory proteins to control many cellular events. The Arabidopsis genome contains two genes, AtRPT2a and AtRPT2b, which encode paralog molecules of the RPT2 subunit of 19S proteasome. We demonstrated that mutation of the AtRPT2a gene causes a specific phenotype of enlarged leaves due to increased cell size in correlation with expanded endoreduplication. This phenotype was also observed in the knockout mutant of AtRPT5a, which encodes one of the paralogs of the RPT5 subunit. Taken together, this suggests that a cell size-specific proteasome consisting of AtRPT2a and AtRPT5a is involved in controlling cell size during leaf development.
泛素/26S 蛋白酶体途径在降解短寿命调节蛋白以控制许多细胞事件中起着核心作用。拟南芥基因组包含两个基因，AtRPT2a 和 AtRPT2b，它们编码 19S 蛋白酶体的 RPT2 亚基的同源分子。我们证明，AtRPT2a 基因突变导致叶片增大的特定表型，这是由于细胞大小增加与内多倍体化扩张相关。在 RPT5 亚基的一个同源物 AtRPT5a 的敲除突变体中也观察到了这种表型。综上所述，这表明由 AtRPT2a 和 AtRPT5a 组成的细胞大小特异性蛋白酶体参与控制叶片发育过程中的细胞大小。
