高等植物多肽激素CLAVATA3(CLV3)對(duì)于植物莖端分生組織干細(xì)胞數(shù)目的維持起著極其重要的作用,。過去幾十年來,，CLAVATA1/CLAVATA2 (CLV1/CLV2) 復(fù)合體被認(rèn)為是CLV3多肽在細(xì)胞膜上的唯一受體。
然而最近的遺傳學(xué)分析篩選到了一個(gè)新的受體蛋白激酶成員—CORYNE(CRN),，并且發(fā)現(xiàn)它在CLV3信號(hào)途徑中起著非常重要的作用,。在一系列遺傳學(xué)分析的基礎(chǔ)上,，新的CLV3信號(hào)轉(zhuǎn)導(dǎo)通路假設(shè)被提出：即CLV1同源二聚體與CLV2/CRN異源復(fù)合體可能平行獨(dú)立地介導(dǎo)CLV3信號(hào),。
然而,，新的假設(shè)僅僅停留在遺傳學(xué)上的預(yù)測(cè)，仍然缺乏進(jìn)一步的生物化學(xué)和細(xì)胞學(xué)的證據(jù),。為了更好地理解這三個(gè)可能的受體蛋白之間的相互關(guān)系,，林金星研究組利用新型的活體下檢測(cè)蛋白質(zhì)相互作用的技術(shù)—螢火蟲熒光素酶互補(bǔ)技術(shù)(Firefly luciferase complementation imaging assay, LCI) 在擬南芥葉肉原生質(zhì)體 (Arabidopsis mesophyll protoplasts) 和煙草葉片 (Nicotiana benthamiana leaves) 兩個(gè)體系中分析了CLV1, CLV2和CRN三個(gè)受體蛋白之間的相互作用。
實(shí)驗(yàn)結(jié)果表明：LCI技術(shù)和免疫共沉淀技術(shù) (Co-immunoprecipitation assay) 都證實(shí)了CLV2在沒有CLV3多肽刺激的情況下可以直接地與CRN發(fā)生相互作用,；外源的CLV3多肽處理,，并不會(huì)明顯地影響CLV2-CRN之間的互作強(qiáng)度；進(jìn)一步的LCI實(shí)驗(yàn)發(fā)現(xiàn)CLV1不能夠與CLV2發(fā)生直接的相互作用,，但能夠與CRN有微弱的相互作用,；除此之外，實(shí)驗(yàn)人員還發(fā)現(xiàn) CRN自身可以形成同源二聚體,，而CLV1或CLV2自身不能形成同源二聚體,。這些生化和細(xì)胞學(xué)結(jié)果對(duì)于新提出的CLV3平行雙通路假設(shè)提供了直接的證據(jù)。（生物谷Bioon.com）
生物谷推薦原文出處：
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.
