Molecular characterization of the rice protein RSS1 required for meristematic activity under stressful conditions

Daisuke Ogawa, Haruka Morita, Tsukaho Hattori, Shin Takeda
Plant Physiology and Biochemistry, 2012, 61 : 54-60  DOI: 10.1016/j.plaphy.2012.09.006;      追溯原文......本站官方QQ群:62473826
Disordered protein; Heat-stable protein; Protein phosphatase 1; Rice; RSS1; Stress

Post embryonic growth of plants depends on cell division activity in the shoot and root meristems, in conjunction with subsequent cell differentiation. Under environmental stress conditions, where plant growth is moderately impaired, the meristematic activity is maintained by mechanisms as yet unknown. We previously showed that the rice protein RSS1, whose stability is regulated depending on the cell cycle phases, is a key factor for the maintenance of meristematic activity under stressful conditions. RSS1 interacts with a catalytic subunit of protein phosphatase 1 (PP1), but other molecular characteristics are largely unknown. Here we show that RSS1 interacts with all the PP1 expressed in the shoot apex of rice. This interaction requires one of the conserved regions of RSS1, which is important for RSS1 function. Interestingly, the recombinant RSS1 protein is highly resistant to heat with respect to its anti-coagulability and binding activity to PP1. The features of RSS1 are reminiscent of those of inhibitor-2 of animals, although it is likely that the mode of function of RSS1 is different from that of inhibitor-2. Noticeably, RSS1 binds to PP1 under extremely high ionic strength conditions in vitro. Therefore, RSS1 possibly functions by forming a stable complex with PP1.


植物胚后发育依赖于茎端和根端分生组织的细胞分裂以及随后的细胞分化。在环境胁迫条件下,植物的生长被部分破坏,而分生组织仍维持有活性,但其中的机制尚不清楚。我们之前发现水稻RSS1蛋白的稳定性受细胞周期阶段的调节,RSS1是维持胁迫条件下分生活性的一个重要因子。RSS1与蛋白磷酸酶PP1 的一个催化亚基互作,但是关于RSS1的其他分子特征还不清楚。这里我们发现RSS1与水稻茎顶端表达的所有PP1互作。这一互作需要RSS1中一个对功能非常重要的保守区域。有意思的是RSS1重组蛋白的抗凝血以及PP1结合活性高度耐热。RSS1的这些特征与动物inhibitor-2类似,虽然RSS1的作用模式与inhibitor-2不同。值得注意的是在体外RSS1在极高离子强度下与PP1结合。因此,RSS1可能与PP1形成稳定的复合物发挥功能。

  盐敏感 RSS1