2016年7月11日，學(xué)術(shù)刊物自然出版集團(tuán)旗下子刊《Nature Communications》雜志在線發(fā)表了*植物研究所張立新研究員發(fā)表的一篇研究論文，研究發(fā)現(xiàn)質(zhì)體與細(xì)胞核的交流涉及了鈣調(diào)節(jié)的MAPK信號(hào)通路。
質(zhì)體是植物細(xì)胞*的細(xì)胞器，可以分為葉綠體、有色體和白色體。葉綠體(chloroplast)含有葉綠素，是植物進(jìn)行光合作用的重要場(chǎng)所。葉綠體的功能特性受到細(xì)胞核基因組的嚴(yán)密調(diào)控。而葉綠體逆向信號(hào)可調(diào)控質(zhì)體和細(xì)胞核基因的表達(dá)，幫助植物應(yīng)對(duì)外界環(huán)境的改變，正確生產(chǎn)葉綠體并維持其功能。不過(guò)，人們對(duì)葉綠體的逆向信號(hào)傳導(dǎo)還知之甚少。
細(xì)胞核能夠感知葉綠體壓力并做出相應(yīng)的反應(yīng)，誘導(dǎo)或抑制編碼質(zhì)體蛋白的細(xì)胞核基因。此前的研究顯示，ABI4在葉綠體逆向信號(hào)通路中抑制LHCB基因。現(xiàn)在研究人員揭示了逆向信號(hào)通路的另一個(gè)調(diào)控機(jī)制。他們發(fā)現(xiàn)，MAP激酶MPK3/MPK6磷酸化并激活A(yù)BI4。而MAPK的活化涉及葉綠體鈣結(jié)合蛋白CAS介導(dǎo)的鈣瞬變。研究表明，葉綠體調(diào)節(jié)的Ca2+信號(hào)會(huì)控制MAPK通路，激活葉綠體逆向信號(hào)鏈中的關(guān)鍵組分。
原文摘要：
Chloroplast retrograde signals play important roles in coordinating the plastid and nuclear gene expression and are critical for proper chloroplast biogenesis and for maintaining optimal chloroplast functions in response to environmental changes in plants. Until now, the signals and the mechanisms for retrograde signalling remain poorly understood. Here we identify factors that allow the nucleus to perceive stress conditions in the chloroplast and to respond accordingly by inducing or repressing specific nuclear genes encoding plastid proteins. We show that ABI4, which is known to repress the LHCB genes during retrograde signalling, is activated through phosphorylation by the MAP kinases MPK3/MPK6 and the activity of these kinases is regulated through 14-3-3ω-mediated Ca2+-dependent scaffolding depending on the chloroplast calcium sensor protein CAS. These findings uncover an additional mechanism in which chloroplast-modulated Ca2+ signalling controls the MAPK pathway for the activation of critical components of the retrograde signalling chain.
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