A cell-cycle-regulated kinase activity phosphorylates plant retinoblastoma protein and contains, in Arabidopsis, a CDKA/cyclin D complex
A cell-cycle-regulated kinase activity phosphorylates plant retinoblastoma protein and contains, in Arabidopsis, a CDKA/cyclin D complex
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DOI：
10.1046/j.1365-313x.2001.01160.x
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发表时间：
2001-11-01
期刊：
影响因子：
7.2
通讯作者：
Gutierrez, C
中科院分区：
文献类型：
--
作者：
Boniotti, MB;Gutierrez, C
细胞周期蛋白依赖性激酶（CDK）的活性对细胞周期转换至关重要。在这里，我们报告的CDK活性，磷酸化视网膜母细胞瘤相关（RBR）蛋白的鉴定。结合RBR并使其磷酸化的CDK/细胞周期蛋白复合物可以从各种植物来源，例如小麦、玉米、拟南芥和烟草，以及从在各种条件下生长的细胞中分离。RBR相关的CDK活性的存在与增殖活性相关，表明RBR的磷酸化是活跃增殖组织中的主要事件。以. thaliana，该活性包含PSTAIRE CDKA和至少细胞周期蛋白D2。此外，该CDK活性是细胞周期调节的，如通过使用高度同步的烟草BY-2细胞的研究所揭示的，其中其在G1晚期和S早期细胞中最大，并且逐渐降低直到G2期。Aphidicolin阻滞而不是roscovitine阻滞的细胞含有PSTAIRE型CDK，其结合并磷酸化RBR。因此，与D型细胞周期蛋白的关联是导致G1晚期CDK激活的可能机制。我们的研究构成了第一份报告，测量在体内形成的CDK/细胞周期蛋白复合物对RBR的活性，在细胞周期依赖性的方式波动的活动。本研究为进一步研究RBR磷酸化对其在细胞周期和发育过程中功能的影响奠定了基础。
The activity of cyclin-dependent kinases (CDK) is crucial for cell-cycle transitions. Here, we report the identification of a CDK activity that phosphorylates the retinoblastoma-related (RBR) protein. A CDK/ cyclin complex that binds to and phosphorylates RBR may be isolated from various plant sources, e.g. wheat, maize, Arabidopsis thaliana and tobacco, and from cells growing under various conditions, The presence of an RBR-associated CDK activity correlates with the proliferative activity, suggesting that phosphorylation of RBR is a major event in actively proliferating tissues. In A. thaliana, this activity comprises a PSTAIRE CDKA and at least cyclin D2. Furthermore, this CDK activity is cell-cycle-regulated, as revealed by studies with highly synchronized tobacco BY-2 cells where it is maximal in late G1 and early S phase cells and progressively decreases until G2 phase. Aphidicolin-arrested but not roscovitine-arrested cells contain a PSTAIRE-type CDK that binds to and phosphorylates RBR. Thus, association with a D-type cyclin is a likely mechanism leading to CDK activation late in G1. Our studies constitute the first report measuring the activity of CDK/cyclin complexes formed in vivo on RBR, an activity that fluctuates in a cell-cycle-dependent manner. This work provides the basis for further studies on the impact of phosphorylation of RBR on its function during the cell cycle and development.