南开校友《Nature》用光控制活细胞移动

　　

生物通报道，来自北卡罗莱大学Lineberger综合癌症研究中心，药理系，生物化学与生物生理系以及Max Planck医学研究生物分子机制研究系的科学家在最新一期的Nature上发表蛋白技术新的研究进展文章，A genetically encoded photoactivatable Rac controls the motility of living cells，首次找到一种可控制活细胞移动的蛋白。

 

文章通讯作者是北卡罗来大学Lineberger综合癌症研究中心的Klaus M Hahn教授和助理教授Yi I Wu，吴博士1996年毕业于南开大学，后赴美留学，现任癌症研究中心的助理教授。

 

细胞功能研究包括细胞活动控制机制的研究，比如，正常细胞如何被蛋白控制其流动性，异常的癌细胞又是如何移动以达到扩散的目的。因此，研究具有精确调控细胞活动能力的蛋白对细胞生物学具有重要意义。

 

Yi I Wu，Klaus M Hahn等人发现一种Rac1编码的蛋白具有控制活细胞移动的能力，Rac1是一种GTP酶，它调控肌动蛋白细胞骨架动态，可因暴露于激光（458nm或437nm）而被激发控制活细胞移动的功能。

 

该蛋白的最大特点是可精确的控制活细胞移动，在精准的时间里完全控制细胞的移动导向。它通过激光的激发精准地产生细胞局部的突起和皱褶，引导细胞运动。相关技术已经在小鼠胚胎细胞中临床应用。

 

研究人员希望在下一步的研究中找出类似功能的蛋白亚类。这将有助于胚胎发育，神经再生和癌症转移的研究。

（生物通 小茜）

生物通推荐原文检索

A genetically encoded photoactivatable Rac controls the motility of living cells

Yi I. Wu1,3, Daniel Frey4, Oana I. Lungu1,2,3, Angelika Jaehrig1,3, Ilme Schlichting4, Brian Kuhlman2,3 & Klaus M. Hahn1,3

 

Department of Pharmacology,

Department of Biochemistry and Biophysics, and,

Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina 27599, USA

Department of Biomolecular Mechanisms, Max Planck Institute for Medical Research, Jahn-Strasse 29, 69120 Heidelberg, Germany

 

【Abstract】

The precise spatio-temporal dynamics of protein activity are often critical in determining cell behaviour, yet for most proteins they remain poorly understood; it remains difficult to manipulate protein activity at precise times and places within living cells. Protein activity has been controlled by light, through protein derivatization with photocleavable moieties1 or using photoreactive small-molecule ligands2. However, this requires use of toxic ultraviolet wavelengths, activation is irreversible, and/or cell loading is accomplished via disruption of the cell membrane (for example, through microinjection). Here we have developed a new approach to produce genetically encoded photoactivatable derivatives of Rac1, a key GTPase regulating actin cytoskeletal dynamics in metazoan cells3, 4. Rac1 mutants were fused to the photoreactive LOV (light oxygen voltage) domain from phototropin5, 6, sterically blocking Rac1 interactions until irradiation unwound a helix linking LOV to Rac1. Photoactivatable Rac1 (PA-Rac1) could be reversibly and repeatedly activated using 458- or 473-nm light to generate precisely localized cell protrusions and ruffling. Localized Rac activation or inactivation was sufficient to produce cell motility and control the direction of cell movement. Myosin was involved in Rac control of directionality but not in Rac-induced protrusion, whereas PAK was required for Rac-induced protrusion. PA-Rac1 was used to elucidate Rac regulation of RhoA in cell motility. Rac and Rho coordinate cytoskeletal behaviours with seconds and submicrometre precision7, 8. Their mutual regulation remains controversial9, with data indicating that Rac inhibits and/or activates Rho10, 11. Rac was shown to inhibit RhoA in mouse embryonic fibroblasts, with inhibition modulated at protrusions and ruffles. A PA-Rac crystal structure and modelling revealed LOV–Rac interactions that will facilitate extension of this photoactivation approach to other proteins.