高等植物多肽激素CLAVATA3(CLV3)对于植物茎端分生组织干细胞数目的维持起着极其重要的作用。过去几十年来，CLAVATA1/CLAVATA2 (CLV1/CLV2) 复合体被认为是CLV3多肽在细胞膜上的唯一受体。
然而最近的遗传学分析筛选到了一个新的受体蛋白激酶成员—CORYNE(CRN)，并且发现它在CLV3信号途径中起着非常重要的作用。在一系列遗传学分析的基础上，新的CLV3信号转导通路假设被提出：即CLV1同源二聚体与CLV2/CRN异源复合体可能平行独立地介导CLV3信号。
然而，新的假设仅仅停留在遗传学上的预测，仍然缺乏进一步的生物化学和细胞学的证据。为了更好地理解这三个可能的受体蛋白之间的相互关系，林金星研究组利用新型的活体下检测蛋白质相互作用的技术—萤火虫荧光素酶互补技术(Firefly luciferase complementation imaging assay, LCI) 在拟南芥叶肉原生质体 (Arabidopsis mesophyll protoplasts) 和烟草叶片 (Nicotiana benthamiana leaves) 两个体系中分析了CLV1, CLV2和CRN三个受体蛋白之间的相互作用。
实验结果表明：LCI技术和免疫共沉淀技术 (Co-immunoprecipitation assay) 都证实了CLV2在没有CLV3多肽刺激的情况下可以直接地与CRN发生相互作用；外源的CLV3多肽处理，并不会明显地影响CLV2-CRN之间的互作强度；进一步的LCI实验发现CLV1不能够与CLV2发生直接的相互作用，但能够与CRN有微弱的相互作用；除此之外，实验人员还发现 CRN自身可以形成同源二聚体，而CLV1或CLV2自身不能形成同源二聚体。这些生化和细胞学结果对于新提出的CLV3平行双通路假设提供了直接的证据。（生物谷Bioon.com）
生物谷推荐原文出处：
The Plant Journal DOI 10.1111/j.1365-313X.2009.04049.x
Analysis of interactions among the CLAVATA3 receptors reveals a direct interaction between CLAVATA2 and CORYNE in Arabidopsis
Yingfang Zhu 1,2,? , Yuqing Wang 1,2,? , Ruili Li 1,2 , Xiufen Song 1 , Qinli Wang 1,2 , Shanjin Huang 1 , Jing Bo Jin 1 , Chun-Ming Liu 1 and Jinxing Lin 1,*
1 Key Laboratory of Photosynthesis and Environmental Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100049, China , and
2 Gradual School of Chinese Academy of Sciences, Beijing, 100049, China
In Arabidopsis, CORYNE (CRN), a new member of the receptor kinase family, was recently isolated as a key player involved in the CLAVATA3 (CLV3) signaling pathway, thereby playing an important role in regulating the development of shoot and root apical meristems. However, the precise relationships among CLAVATA1 (CLV1), CLAVATA2 (CLV2), and CRN receptors remain unclear. Here, we demonstrate the subcellular localization of CRN and analyze the interactions among CLV1, CLV2, and CRN using firefly luciferase complementation imaging (LCI) assays in both Arabidopsis mesophyll protoplasts and Nicotiana benthamiana leaves. Fluorescence targeting showed that CRN was localized to the plasma membrane. The LCI assays coupled with co-immunoprecipitation assays demonstrated that CLV2 can directly interact with CRN in the absence of CLV3. Additional LCI assays showed that CLV1 did not interact with CLV2, but can interact weakly with CRN. We also found that CLV1 can interact with CLV2–CRN heterodimers, implying that these three proteins may form a complex. Moreover, CRN, rather than CLV1 and CLV2, was able to form homodimers without CLV3 stimulation. Taken together, our results add direct evidence to the newly proposed two-parallel receptor pathways model and therefore provide new insights into the CLV3 signaling pathway.
