Bi Guozhi, Liebrand Thomas W H, Cordewener Jan H G, America Antoine H P, Xu Xiangyang, Joosten Matthieu H A J
College of Horticulture; Northeast Agricultural University; Harbin, PR China; Laboratory of Phytopathology; Wageningen University; Wageningen, The Netherlands.
Laboratory of Phytopathology; Wageningen University; Wageningen, The Netherlands; Centre for BioSystems Genomics; Wageningen, The Netherlands.
Plant Signal Behav. 2014;9(2):e27937. doi: 10.4161/psb.27937. Epub 2014 Feb 13.
Plants employ a large number of receptors localizing to the cell surface to sense extracellular signals. Receptor-like proteins (RLPs) form an important group of such trans-membrane receptors, containing an extracellular domain which is involved in signal perception and a short cytoplasmic domain. In contrast to receptor-like kinases (RLKs), RLPs lack a cytoplasmic kinase domain. How intracellular signaling is triggered downstream of RLPs upon perception of an extracellular signal, is therefore still poorly understood. Recently, the RLK SOBIR1 (Suppressor Of BIR1-1) was identified as an essential regulatory RLK of various RLPs involved in plant immunity against fungal pathogens. (1) Given that SOBIR1 appears to be a crucial component of RLP-containing complexes, we aimed to identify additional proteins interacting with SOBIR1. Here, we report on the immunopurification of a functional Arabidopsis thaliana (At)SOBIR1-yellow fluorescent protein (YFP) fusion protein stably expressed in Arabidopsis, followed by mass-spectrometry to identify co-purifying proteins. Interestingly, and in line with various studies showing interaction between RLPs and SOBIR1, we discovered that AtSOBIR1 interacts with AtRLP23, an RLP of which the function is currently unknown.
植物利用大量定位于细胞表面的受体来感知细胞外信号。类受体蛋白（RLP）构成了这类跨膜受体中的一个重要群体，其包含一个参与信号感知的细胞外结构域和一个短的胞质结构域。与类受体激酶（RLK）不同，RLP缺乏胞质激酶结构域。因此，在感知细胞外信号后，RLP下游如何触发细胞内信号传导仍知之甚少。最近，RLK SOBIR1（BIR1-1的抑制因子）被鉴定为参与植物抗真菌病原体免疫的各种RLP的重要调节性RLK。（1）鉴于SOBIR1似乎是含RLP复合物的关键组成部分，我们旨在鉴定与SOBIR1相互作用的其他蛋白质。在此，我们报告了对在拟南芥中稳定表达的功能性拟南芥（At）SOBIR1-黄色荧光蛋白（YFP）融合蛋白进行免疫纯化，随后通过质谱鉴定共纯化蛋白。有趣的是，与各种显示RLP和SOBIR1之间相互作用的研究一致，我们发现AtSOBIR1与AtRLP23相互作用，AtRLP23是一种功能目前未知的RLP。
