2016年12月23日,國際植物科學頂級期刊《TheplantCell》線上發表了南方科技大學生物系李瑞熙教授課題組與美國加州大學河邊分校Natasha Raikhel 院士研究組合作題為Different Endomembrane Trafficking Pathways Establish Apical and Basal Polarities的研究論文。 研究發現一種小分子化合物- Endosidin 16 (ES16) 通過調控一類小G蛋白-RabA2A GTPase特異性誘導頂端極性定位的生長素轉運載體PIN蛋白形成胞內聚合物並改變其頂端極性分佈但不影響 PIN蛋白的基底膜定位。 研究結果第一次揭示了生長素轉運蛋白頂端極性定位的內膜分選機制。 南方科技大學助理教授李瑞熙為文章第一作者, 美國加州大學河邊分校的Glenn R. Hicks為論文通訊作者。
生長素是調控植物胚胎發育和胚後發育的關鍵影響因數。
為了探索調控 PIN 蛋白頂端極性定位的細胞生物學機制, 李瑞熙研究組進行了一次小規模化合物篩選, 目的在於發現能夠特異性干擾 PIN 蛋白頂端極性分佈但不影響基底極性分佈的化合物。 通過篩選, 他們發現了一種小分子化合物- Endosidin 16 (ES16), 能夠特異性誘導頂端極性定位的 PIN2 蛋白形成胞內聚合物並改變其頂端極性分佈但不影響 PIN1 的基底膜定位。 進一步研究發現, ES16 對PIN蛋白頂端極性定位的調控作用是通過作用於一類小G蛋白RabA2A GTPase 來實現的。 蛋白序列比對分析顯示RabA2A與動物細胞中的Rab11 GTPase同源。
圖1. ES16處理引起PIN2形成胞內聚合物並改變頂端極性分佈但不影響PIN1基底極性。
原文連結:
Different Endomembrane Trafficking Pathways Establish Apical and Basal Polarities
原文摘要:
The endomembrane system is an interconnected network required to establish signal transduction, cell polarity, and cell shape in response to developmental or environmental stimuli. In the model plant Arabidopsis thaliana, there are numerous markers to visualize polarly localized plasma membrane proteins utilizing endomembrane trafficking. Previous studies have shown that the large ARF-GEF GNOM plays a key role in the establishment of basal (rootward) polarity, whereas the apically (shootward) polarized membrane proteins undergo sorting via different routes. However, the mechanism that maintains apical polarity is largely unknown. Here, we used a chemical genomic approach and identified the compound endosidin 16 (ES16), which perturbed apically localized plasma membrane proteins without affecting basal polarity. We demonstrated that ES16 is an inhibitor for recycling of apical, lateral, and nonpolar plasma membrane proteins as well as biosynthetic secretion, leaving the basal proteins as the only exceptions not subject to ES16 inhibition. Further evidence from pharmaceutical and geneticdata revealed that ES16 effects are mediated through the regulation of small GTPase RabA proteins and that RabA GTPases work in concert with the BIG clade ARF-GEF to modulate the nonbasal trafficking. Our results reveal that ES16 defines a distinct pathway for endomembrane sorting routes and is essential for the establishment of cell polarity.
作者:李瑞熙 點擊:次