The maize Gα gene COMPACT PLANT2 functions in CLAVATA signalling to control shoot meristem size
The maize Gα gene COMPACT PLANT2 functions in CLAVATA signalling to control shoot meristem size
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DOI：
10.1038/nature12583
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发表时间：
2013-10-24
期刊：
影响因子：
64.8
通讯作者：
Jackson, David
中科院分区：
文献类型：
--
作者：
Bommert, Peter;Il Je, Byoung;Jackson, David
芽生长依赖于分生组织，由CLAVATA途径和WUSCHEL同源框基因之间的负反馈回路维持的干细胞池（1）。CLAVATA信号传导涉及一种分泌肽CLAVATA 3（CLV 3）（2）及其被细胞表面富亮氨酸重复序列（LRR）受体感知，包括CLV 1受体激酶（3）和LRR受体样蛋白CLV 2（参考文献4）。然而，对这些受体下游的信号传导机制知之甚少，特别是缺乏信号传导结构域的LRR受体样蛋白（5）。在这里，我们表明，玉米COMPACT PLANT 2（CT 2）编码预测的α亚基（G α）的异源三聚体GTP结合蛋白。玉米ct 2表型类似于拟南芥棒突变体，遗传，生化和功能测定表明，CT 2/G α传递干细胞限制性信号从CLAVATA LRR受体，这表明一个新的功能，G α信号在植物中。异三聚体GP结合蛋白是膜相关分子开关，通常通过配体与相关七次跨膜（7 TM）G蛋白偶联受体（GPCR）结合而激活（6）。最近的研究质疑了植物异源三聚体G蛋白与典型GPCR相互作用的观点（7），我们的研究结果表明，单次跨膜受体在植物中充当GPCR，挑战了GPCR仅是7 TM蛋白的教条。
Shoot growth depends on meristems, pools of stem cells that are maintained by a negative feedback loop between the CLAVATA pathway and the WUSCHEL homeobox gene(1). CLAVATA signalling involves a secreted peptide, CLAVATA3 (CLV3)(2), and its perception by cell surface leucine-rich repeat (LRR) receptors, including the CLV1 receptor kinase(3) and a LRR receptor-like protein, CLV2 (ref. 4). However, the signalling mechanisms downstream of these receptors are poorly understood, especially for LRR receptor-like proteins, which lack a signalling domain(5). Here we show that maize COMPACT PLANT2 (CT2) encodes the predicted alpha-subunit (G alpha) of a heterotrimeric GTP binding protein. Maize ct2 phenotypes resemble Arabidopsis thaliana clavata mutants, and genetic, biochemical and functional assays indicate that CT2/G alpha transmits a stem-cell-restrictive signal from a CLAVATA LRR receptor, suggesting a new function for G alpha signalling in plants. Heterotrimeric GTP-binding proteins are membrane-associated molecular switches that are commonly activated by ligand binding to an associated seven-pass transmembrane (7TM) G-protein-coupled receptor (GPCR)(6). Recent studies have questioned the idea that plant heterotrimeric G proteins interact with canonical GPCRs(7), and our findings suggest that single pass transmembrane receptors act as GPCRs in plants, challenging the dogma that GPCRs are exclusively 7TM proteins.