以色列特拉維夫大學(xué)分子生物學(xué)和植物生態(tài)學(xué)系的肖·雅洛夫斯基教授在植物中發(fā)現(xiàn)了一種起“開關(guān)”作用的脂肪分子,，它的開啟或關(guān)閉可以控制植物細(xì)胞的生長(zhǎng)。他認(rèn)為人體內(nèi)類似機(jī)制或許可以阻止癌細(xì)胞轉(zhuǎn)移,。
研究顯示,，植物中的這種脂肪分子對(duì)負(fù)責(zé)細(xì)胞生長(zhǎng)的ROPs蛋白質(zhì)具有控制作用。而人體中也存在與ROPs非常相似的蛋白質(zhì),，它們參與傷口愈合,，促進(jìn)腦神經(jīng)細(xì)胞發(fā)育，同時(shí)也發(fā)出化學(xué)信號(hào)告訴癌細(xì)胞何時(shí)轉(zhuǎn)移,。
當(dāng)ROPs蛋白質(zhì)與稱為GTP的小分子結(jié)合后,，這種小分子就會(huì)分裂為另一個(gè)GDP分子，GDP分子一旦與ROPs結(jié)合,，ROPs就會(huì)失去活性?，F(xiàn)在，研究人員已制造出一種變異分子,，可以對(duì)ROPs蛋白質(zhì)與GTP分子的結(jié)合進(jìn)行控制,。
雅洛夫斯基表示，人和植物雖然是完全不同的有機(jī)體,，但也共享一些生物機(jī)制,，同時(shí)存在于人體和植物內(nèi)的ROPs蛋白質(zhì)就是如此。當(dāng)這些蛋白質(zhì)開啟時(shí),，可以促使細(xì)胞分裂和生長(zhǎng),，如利用基因工程技術(shù)將人體內(nèi)相關(guān)的ROPs關(guān)閉，即可起到延緩或終止癌細(xì)胞生長(zhǎng)的作用,，現(xiàn)在他們距這一目標(biāo)只有一步之遙,。
除應(yīng)用于人體外，這項(xiàng)研究還可惠及農(nóng)業(yè)領(lǐng)域。研究人員設(shè)計(jì)的另一種變異分子可誘使植物認(rèn)為是病原體而發(fā)起攻擊,，從而產(chǎn)生避免感染的生物防御系統(tǒng),，減少化學(xué)殺蟲劑的使用（鄭曉春）。(生物谷Bioon.com)
>>>借著上海世博會(huì)的良好契機(jī),，"第一屆腫瘤基礎(chǔ)和轉(zhuǎn)化醫(yī)學(xué)國(guó)際研討會(huì)"將于2010年10月12日在中國(guó)上海盛大開幕,，這將為廣大活躍在腫瘤基礎(chǔ)和轉(zhuǎn)化醫(yī)學(xué)第一線的科研工作者提供一個(gè)互動(dòng)交流的平臺(tái)。
會(huì)議官方網(wǎng)站：www.cancerasia.org
生物谷推薦原文出處：
Current Biology doi:10.1016/j.cub.2010.03.057
An S-Acylation Switch of Conserved G Domain Cysteines Is Required for Polarity Signaling by ROP GTPases
Nadav Sorek, Oshik Segev, Orit Gutman, Einat Bar, Sandra Richter, Limor Poraty, Joel A. Hirsch, Yoav I. Henis, Efraim Lewinsohn, Gerd Jürgens, Shaul Yalovsky
Rho GTPases are master regulators of cell polarity [1]. For their function, Rhos must associate with discrete plasma membrane domains [2]. Rho of Plants (ROPs) or RACs comprise a single family [3,4,5]. Prenylation and S-acylation of hypervariable domain cysteines of Ras and Rho GTPases are required for their function [6,7,8,9,10,11]; however, lipid modifications in the G domain have never been reported. Reversible S-acylation involves the attachment of palmitate (C16:0) or other saturated lipids to cysteines through a thioester linkage and was implicated in the regulation of signaling [12]. Here we show that transient S-acylation of Arabidopsis AtROP6 takes place on two conserved G domain cysteine residues, C21 and C156. C21 is relatively exposed and is accessible for modification, but C156 is not, implying that its S-acylation involves a conformational change. Fluorescence recovery after photobleaching beam-size analysis [13] shows that S-acylation of AtROP6 regulates its membrane-association dynamics, and detergent-solubilization studies indicate that it regulates AtROP6 association with lipid rafts. Site-specific acylation-deficient AtROP6 mutants can bind and hydrolyze GTP but display compromised effects on polar cell growth, endocytic uptake of the tracer dye FM4-64, and distribution of reactive oxygen species. These data reveal an S-acylation switch that regulates Rho signaling.
