Antagonistic jacalin-related lectins regulate the size of ER body-type β-glucosidase complexes in Arabidopsis thaliana
Antagonistic jacalin-related lectins regulate the size of ER body-type β-glucosidase complexes in Arabidopsis thaliana
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DOI：
10.1093/pcp/pcn075
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发表时间：
2008-06-01
影响因子：
4.9
通讯作者：
Hara-Nishimura, Ikuko
中科院分区：
文献类型：
--
作者：
Nagano, Atsushi J.;Fukao, Yoichiro;Hara-Nishimura, Ikuko
PYK 10/BGLU 23是一种β-葡萄糖苷酶，是内质网体的主要蛋白质，内质网体是可能参与防御系统的内质网（ER）衍生的细胞器。PYK 10有活性和非活性形式。活性PYK 10分子形成直径为0.65 μ m至> 70 μ m的大复合物。我们在纯化的PYK 10复合物中鉴定了三种β-葡萄糖苷酶（PYK 10、BGLU 21和BGLU 22）、五种jacalin相关凝集素（JAL）和一种GDSL脂肪酶样蛋白（GLL）。与Col-0相比，没有ER体的nai 1 -1突变体中JAL和GLL的表达水平较低。PYK 10的亚细胞定位被预测为不同于JAL和GLL的定位。这表明当亚细胞结构被病原体破坏时，PYK 10与其伴侣（JAL和GLL）相互作用。发现PYK 10复合物在pbp 1 -1和jal 22 -1突变体中比在Col-0中大，而在jal 23 -1、jal 31 -1和jal 31 -2突变体中比在Col-0中小。这些结果表明，具有相反作用的两种类型的JAL拮抗性地调节PYK 10复合物的大小。我们将两种类型的凝集素定义为聚合酶型凝集素和通道型凝集素。有趣的是，聚合酶型凝集素（JAL 31和JAL 23）的最接近的同系物是通道型凝集素（PBP 1/JAL 30和JAL 22）。这里报道的聚合酶型和通道型凝集素对是在基因复制后进化出新功能的基因的很好的例子（新功能化）。
PYK10/BGLU23 is a beta-glucosidase that is a major protein of ER bodies, which are endoplasmic reticulum (ER)-derived organelles that may be involved in defense systems. PYK10 has active and inactive forms. Active PYK10 molecules form large complexes with diameters ranging from 0.65 mu m to > 70 mu m. We identified three beta-glucosidases (PYK10, BGLU21 and BGLU22), five jacalin-related lectins (JALs) and a GDSL lipase-like protein (GLL) in the purified PYK10 complex. Expression levels of JALs and GLLs were lower in the nai1-1 mutant, which has no ER bodies, than in Col-0. The subcellular localization of PYK10 is predicted to be different from the localizations of JALs and GLLs. This suggests that PYK10 interacts with its partners (JALs and GLLs) when the subcellular structure is destroyed by pathogens. The PYK10 complex was found to be larger in the pbp1-1 and jal22-1 mutants than in Col-0, while it was smaller in the jal23-1, jal31-1 and jal31-2 mutants than in Col-0. These results show that two types of JALs having opposite roles regulate the size of the PYK10 complex antagonistically. We define the two types of lectins as a polymerizer-type lectin and an inhibitor-type lectin. Interestingly, the closest homologs of polymerizer-type lectins (JAL31 and JAL23) were inhibitor-type lectins (PBP1/JAL30 and JAL22). The pairs of polymerizer-type and inhibitor-type lectins reported here are good examples of genes that have evolved new functions after gene duplication (neofunctionalization).